Solifenacin succinate

What it is

Solifenacin succinate is a prescription-only tablet, taken by mouth once a day, in 5 mg and 10 mg strengths. It is a competitive muscarinic (anticholinergic) receptor blocker, given for the symptoms of an overactive bladder. It is absorbed almost completely (bioavailability about 90%), broken down mainly by the liver enzyme CYP3A4, and clears slowly, with a half-life of roughly 45 to 68 hours after repeated dosing. It is not a nutrient and is not found in food.

What the research says

The randomised evidence shows a real but modest effect. Across 104 placebo-controlled trials of this drug class, anticholinergics cut about 0.85 trips to the toilet per 24 hours and about 0.85 urgency episodes per 24 hours more than placebo, at moderate certainty, and improved quality of life only slightly at low certainty. In solifenacin's own four 12-week registration trials the drug reduced voids by 2.3 (5 mg) or 2.7 (10 mg) per 24 hours against 1.4 on placebo, and leakage episodes by 1.5 or 1.8 against 1.1 on placebo. The drying side effects are common and dose-related: dry mouth reached 27.6% at 10 mg against 4.2% on placebo. Whether benefit lasts beyond a year, or persists after stopping, has not been established, and observational data link long cumulative use to a higher recorded rate of dementia diagnoses.

Evidence grade: Well established.

How it works

Drug class: Competitive muscarinic receptor antagonist (antimuscarinic / anticholinergic bladder relaxant)

Nerves release acetylcholine onto muscarinic receptors on the smooth muscle of the bladder wall, which makes the muscle contract. Solifenacin competes with acetylcholine at those receptors, so the bladder muscle contracts less readily and holds more urine before signalling urgency. The same receptors sit in salivary glands, bowel, eye and brain, which is why dry mouth, constipation, blurred vision and confusion follow from the same action. (Source 1)

What it is used for

• Four 12-week placebo-controlled trials in 3,027 adults showed a statistically significant reduction in voids and leakage episodes, and a Cochrane review of 104 trials of the whole drug class found moderate-certainty evidence of a modest benefit. The size of the benefit over placebo is about one fewer leak and one fewer void per day, not abolition of symptoms. Evidence: established. (Source 2)
• The tablet label states plainly that safety and effectiveness have not been established in children. Use of the tablet below 18 is therefore off-label and we found no paediatric trial evidence for the tablet in the sources we searched. Evidence: unknown. (Source 3)
• A 2026 systematic review of five randomised trials lasting at least a year found that solifenacin 5 mg plus mirabegron 50 mg may beat either drug alone on volume voided, leakage and frequency, but heterogeneity above 58% stopped the authors pooling the efficacy data at all, so only a narrative synthesis was possible. Evidence: limited. (Source 4)

Interactions

• Strong CYP3A4 inhibitors, for example the antifungal ketoconazole (pharmacokinetic study): Solifenacin is broken down mainly by the liver enzyme CYP3A4. Drugs that strongly block that enzyme raise solifenacin levels in the blood, so the label caps the dose at 5 mg a day when one is taken alongside. The label’s own pharmacokinetic study found that ketoconazole 400 mg once daily for 21 days raised peak solifenacin levels 1.5-fold and total exposure 2.7-fold. (Source 5)
• Food and meals (pharmacokinetic study): Food makes almost no difference. A single 10 mg dose taken with food raised peak level by 4% and total exposure by 3%, so the tablet can be taken with or without a meal. (Source 6)
• Medicines known to prolong the QT interval (label): Solifenacin lengthens the QT interval slightly at high exposure, and QT prolongation and Torsade de Pointes have been reported after marketing, so the label advises against it in people already at high risk of QT prolongation or taking QT-prolonging drugs. (Source 7)
• Other anticholinergic medicines taken at the same time (total anticholinergic burden) (theoretical): Stacking several drying drugs stacks the dry mouth, constipation, retention and confusion that come from the same receptor block; that part is mechanistic reasoning rather than a measured interaction. Separately, the dementia case-control study counted cumulative dose and adjusted for the use of other anticholinergic drugs, which is how that literature handles the combined load rather than any single tablet. Its design and limits are carried on the dementia finding in this entry. (Source 8)
• Alcohol (label): No alcohol interaction is documented for solifenacin. The entire drug-interactions section of the US label consists of one subsection, on strong CYP3A4 inhibitors; alcohol, grapefruit juice and dietary supplements are not mentioned anywhere in it. That is an absence of documentation, not evidence of safety, and solifenacin can cause somnolence in its own right. (Source 5)
• Warfarin (pharmacokinetic study): A crossover study gave a single 25 mg dose of warfarin during 16 days of solifenacin 10 mg a day. Blood levels of both forms of warfarin changed by a few per cent in either direction, which is a change of no practical size. (Source 6)
• Combined oral contraceptives (ethinyl estradiol with levonorgestrel) (pharmacokinetic study): In a crossover study solifenacin 10 mg a day for 10 days changed the blood levels of both contraceptive hormones by no more than 3%. Unlike carbamazepine, solifenacin does not appear to make hormonal contraception less effective. (Source 6)

Stopping it

• Whether any benefit survives stopping has not been established. The Cochrane review of 104 placebo-controlled trials says so directly, and notes that withdrawals from the trials because of side effects were higher on every anticholinergic except tolterodine. (Source 9)
• Side effects, not failure of effect, were the commonest documented reason for stopping in the registration trials, and dry mouth led the list at 1.5%. (Source 10)
• There is no withdrawal syndrome described for solifenacin, and no dependence. Because the half-life after repeated dosing is long, about 45 to 68 hours, the drug and its drying effects take several days to wash out; in volunteers given five times the maximum dose, antimuscarinic effects resolved within 7 days of stopping. (Source 6)
• When antimuscarinic effects on the brain appear, the label's instruction is dose reduction or stopping the drug rather than adding something to counter them. (Source 11)

What goes wrong

Dry mouth, constipation, blurred vision and urinary retention are all commoner on solifenacin than placebo and get worse at the 10 mg dose. (Source 10)

• Randomized trial, Moderate certainty.
• Size: 1,811 adults on solifenacin and 1,216 on placebo across four randomised placebo-controlled trials.
• Who: Adults with overactive bladder.
• How long: Up to 12 weeks.
• Result: Dry mouth 4.2% placebo, 10.9% on 5 mg, 27.6% on 10 mg; constipation 2.9%, 5.4%, 13.4%; blurred vision 1.8%, 3.8%, 4.8%; urinary retention 0.6%, 0%, 1.4%; dry eyes 0.6%, 0.3%, 1.6%; dry mouth was the most frequent reason for stopping, at 1.5%.
• Funding: Not stated in the label.

The incidence of dry mouth and constipation in patients treated with solifenacin succinate tablets was higher in the 10 mg dose group compared to the 5 mg dose group.

Serious bowel obstruction occurred in the 10 mg arm of the 12-week trials, in single patients. (Source 10)

• Randomized trial, Low certainty.
• Size: Three single cases among 1,233 patients given 10 mg.
• Who: Adults with overactive bladder in the four double-blind trials.
• How long: 12 weeks.
• Result: Severe faecal impaction, colonic obstruction and intestinal obstruction in one patient each, all in the 10 mg group; angioneurotic oedema in one patient on 5 mg.
• Funding: Not stated in the label.

In the four 12-week double-blind clinical trials, severe fecal impaction, colonic obstruction, and intestinal obstruction were reported in one patient each, all in the solifenacin succinate tablets 10 mg group.

Dry mouth and urinary retention are roughly three and a half times as frequent on an anticholinergic as on placebo, and more people withdraw because of side effects. (Source 12)

• Systematic review, Low certainty.
• Size: Dry mouth 66 studies, 38,368 participants; urinary retention 17 studies, 7,862 participants; withdrawals 61 studies, 36,943 participants.
• Who: Adults with overactive bladder syndrome.
• How long: End of treatment period.
• Result: Dry mouth RR 3.50 (95% CI 3.26 to 3.75); urinary retention RR 3.52 (95% CI 2.04 to 6.08); withdrawal due to adverse events RR 1.37 (95% CI 1.21 to 1.56); all low-certainty evidence.
• Funding: Independent; 'none known' declared by all authors.

Compared to placebo, anticholinergics may result in an increase in dry mouth adverse events (RR 3.50, 95% CI 3.26 to 3.75; 66 studies, 38,368 participants; low-certainty evidence), and may result in an increased risk of urinary retention (RR 3.52, 95% CI 2.04 to 6.08; 17 studies, 7862 participants; low-certainty evidence).

Three times the maximum dose lengthened the QT interval by a mean of 8 msec, and QT prolongation and Torsade de Pointes have been reported after marketing. (Source 7)

• Randomized trial, Moderate certainty.
• Size: 76 healthy women.
• Who: Healthy female volunteers aged 19 to 79.
• How long: Multi-dose sequential escalation study.
• Result: Mean increase in the Fridericia-corrected QT interval of 8 msec (90% CI, 4, 13) at 30 mg; the effect appeared smaller at 10 mg and smaller than therapeutic-dose moxifloxacin, the positive control.
• Funding: Not stated in the label.

Limit of this finding: This was a dose-ranging study in 76 healthy women, not a study in patients, and the label itself says the confidence intervals for solifenacin and for the moxifloxacin positive control overlapped and that the study was not designed to compare them statistically. The 8 msec figure is a mean at three times the maximum licensed dose, with a 90% confidence interval of 4 to 13 msec.

solifenacin succinate 30 mg (three times the largest maximum recommended dose in adult patients) was associated with a mean increase in the Fridericia-corrected QT interval of 8 msec (90% CI, 4, 13)

Post-marketing reports include QT prolongation, Torsade de Pointes, delirium, hallucinations, ileus, renal impairment and glaucoma, with no reliable frequency attached. (Source 13)

• Case series, Very low certainty.
• Size: Spontaneous reports from a population of uncertain size.
• Who: Patients taking solifenacin in and outside the United States.
• How long: Post-approval, open-ended.
• Result: No rates can be calculated; the label states frequency cannot be reliably estimated and causality cannot be established.
• Funding: Not stated in the label.

Cardiac disorders: QT prolongation, Torsade de Pointes, atrial fibrillation, tachycardia, palpitations;

Antimuscarinic central nervous system effects including confusion, hallucinations and somnolence are recognised with solifenacin and the label tells prescribers to monitor for them after starting or increasing the dose. (Source 11)

• Official position, Low certainty.
• Size: Not quantified in this section.
• Who: Patients treated with solifenacin.
• How long: Particularly after starting treatment or raising the dose.
• Result: No rate given in this section; dizziness was 1.9% on 5 mg, 1.8% on 10 mg and 1.8% on placebo in the trials.
• Funding: Not applicable.

A variety of CNS antimuscarinic adverse reactions have been reported, including headache, confusion, hallucinations, and somnolence. Monitor patients for signs of antimuscarinic CNS adverse reactions, particularly after beginning treatment or increasing the dose.

In a nested case-control study of 170,742 people with dementia, cumulative solifenacin use was associated with a higher rate of dementia diagnosis; this is an association in routine records, not a demonstration of cause. (Source 8)

• Case-control study, Low certainty.
• Size: 170,742 patients with incident dementia matched to 804,385 controls.
• Who: Adults aged 55 and over in English general practice (CPRD GOLD) with linked hospital records, 2006 to 2022; 62.6% women, median age 83.
• How long: Cumulative exposure counted 3 to 16 years before the dementia diagnosis.
• Result: Any anticholinergic overactive-bladder drug adjusted OR 1.18 (95% CI 1.16 to 1.20); solifenacin succinate 1.18 (1.09 to 1.27) at 366-1095 standardised daily doses and 1.29 (1.19 to 1.39) above 1095; oxybutynin 1.31 (1.21 to 1.42) and 1.28 (1.15 to 1.43); no significant increase for darifenacin, fesoterodine, flavoxate, propiverine or trospium.
• Funding: Supported by the NIHR School for Primary Care Research; one author reports unrelated industry research grants.

Limit of this finding: This is an association found in routine general-practice records, not an experiment. People prescribed more anticholinergic drug are also people with more bladder disease, more other illness and more contact with doctors, and the study cannot separate those from the drug. The odds ratio of 1.18 is small, and the design cannot show that stopping or avoiding solifenacin would change anyone's chance of dementia.

The risk of dementia was substantially increased with the use of oxybutynin hydrochloride (adjusted odds ratio 1.31, 95% CI 1.21 to 1.42 and 1.28, 1.15 to 1.43 for use of 366-1095 and >1095 total standardised daily doses, respectively), solifenacin succinate (1.18, 1.09 to 1.27 and 1.29, 1.19 to 1.39), and tolterodine tartrate (1.27, 1.19 to 1.37 and 1.25, 1.17 to 1.34).

Solifenacin is contraindicated where the bladder or stomach cannot empty and in uncontrolled narrow-angle glaucoma, and can itself worsen urinary retention and kidney injury in outlet obstruction. (Source 14)

• Official position, Certainty not rated.
• Size: Not applicable.
• Who: Patients with urinary retention, gastric retention, uncontrolled narrow-angle glaucoma or hypersensitivity.
• How long: Not applicable.
• Result: No numbers; a categorical contraindication.
• Funding: Not applicable.

Solifenacin succinate tablets are contraindicated in patients: With urinary retention [see Warnings and Precautions (5.2)], With gastric retention [see Warnings and Precautions (5.3)], With uncontrolled narrow-angle glaucoma [see Warnings and Precautions (5.5)], and

Blood levels of solifenacin more than double in severe kidney impairment and the half-life doubles in moderate liver impairment, which is why the label caps the dose at 5 mg in those situations. (Source 6)

• Blood level study, Moderate certainty.
• Size: Not stated in this section; separate single-dose and multiple-dose pharmacokinetic studies.
• Who: Volunteers and patients with severe renal impairment, moderate hepatic impairment, or aged 65 to 80.
• How long: Single 10 mg doses and multiple-dose studies.
• Result: Severe renal impairment: 2.1-fold increase in AUC and 1.6-fold increase in half-life. Moderate hepatic impairment: 2-fold increase in half-life and 35% increase in AUC. Age 65 to 80: Cmax, AUC and half-life 20-25% higher than in volunteers aged 18 to 55. Ketoconazole 400 mg once daily for 21 days raised mean Cmax and AUC 1.5-fold and 2.7-fold.
• Funding: Not stated in the label.

Limit of this finding: These are blood-level studies, not outcome studies: they show how much drug accumulates, not how many people were harmed. The label prints "principally to ∝1-acid glycoprotein" using a proportional-to sign where it means alpha-1, and "600L" with no space; both are the label's own characters and have been kept.

In studies with solifenacin succinate 10 mg, there was a 2.1-fold increase in AUC and a 1.6-fold increase in t1/2 of solifenacin in patients with severe renal impairment compared to subjects with normal renal function [see Use in Specific Populations (8.6)].

What the evidence supports

Across the whole anticholinergic class, the reduction in urgency episodes and in daily voids over placebo is around 0.85 per 24 hours, at moderate certainty. (Source 12)

• Systematic review, Moderate certainty.
• Size: 104 studies; 47,106 people in the studies that reported numbers; the urgency analysis used 23 studies and 16,875 participants and the micturition analysis 30 studies and 19,395 participants.
• Who: Adults with overactive bladder syndrome.
• How long: End of treatment period in the included trials; the review notes trials were short.
• Result: Mean number of urgency episodes per 24 hours MD 0.85 lower (95% CI 1.03 lower to 0.67 lower); micturitions per 24 hours MD 0.85 lower (95% CI 0.98 lower to 0.73 lower); patient perception of cure or improvement RR 1.38 (95% CI 1.15 to 1.66)
• Funding: Independent; the review's conflict-of-interest statement records 'none known' for all six authors.

Anticholinergics are probably better than placebo in terms of patient perception of cure or improvement (risk ratio (RR) 1.38, 95% CI 1.15 to 1.66; 9 studies, 8457 participants; moderate-certainty evidence), and the mean number of urgency episodes per 24-hour period (MD 0.85 lower, 95% CI 1.03 lower to 0.67 lower; 23 studies, 16,875 participants; moderate-certainty evidence).

In solifenacin's own four registration trials the absolute reduction over placebo was about 0.9 to 1.3 fewer voids and 0.4 to 0.7 fewer leakage episodes per 24 hours. (Source 15)

• Randomized trial, Moderate certainty.
• Size: 3,027 patients (1,811 on solifenacin, 1,216 on placebo) across four trials.
• Who: Adults with overactive bladder symptoms for at least 3 months; 93% Caucasian, 80% female, mean age 58.
• How long: 12 weeks, with a 40-week open-label extension.
• Result: Micturitions per 24 hours fell by 2.3 on 5 mg and 2.7 on 10 mg versus 1.4 on placebo; incontinence episodes per 24 hours fell by 1.5 and 1.8 versus 1.1 on placebo; volume voided rose 32.3 mL and 42.5 mL versus 8.5 mL; all p < 0.001.
• Funding: Not stated in the label; these are the manufacturer's registration trials.

Limit of this finding: The label points this passage at per-study Tables 3 through 6, which the quoted block does not contain. The numbers given here are the pooled across-trial figures the label states in prose; the per-study breakdown sits in tables that are not reproduced, so treat these as averages across the four trials rather than results of any single trial.

The mean reduction in the number of micturitions per 24 hours was significantly greater with solifenacin succinate tablets 5 mg (2.3; p < 0.001) and solifenacin succinate tablets 10 mg (2.7; p < 0.001) compared to placebo (1.4).

Head to head against immediate-release tolterodine, solifenacin was modestly better on patient-reported improvement and leakage and had less dry mouth. (Source 16)

• Systematic review, Low certainty.
• Size: 86 trials, 31,249 adults in the whole review; the solifenacin-versus-tolterodine comparisons drew on two to four trials each.
• Who: Adults with overactive bladder symptoms or detrusor overactivity.
• How long: Mostly 12 weeks.
• Result: Quality of life SMD -0.12 (95% CI -0.23 to -0.01); patient reported cure/improvement RR 1.25 (95% CI 1.13 to 1.39); leakage episodes per 24 h WMD -0.30 (95% CI -0.53 to -0.08); urgency episodes per 24 h WMD -0.43 (95% CI -0.74 to -0.13); dry mouth after sensitivity analysis RR 0.69 (95% CI 0.51 to 0.94)
• Funding: Independent; conflict of interest 'None declared'

Limit of this finding: This Cochrane abstract runs several sentences together with no space after the full stop ("useable data.Tolterodine versus oxybutynin:", "Different doses of fesoterodine:The recommended starting dose"). That spacing is how the published abstract prints and has been kept. It does not affect any number. The comparisons also come from two to four trials each, so the differences are small and rest on little data.

Solifenacin versus tolterodine: There were statistically significant differences for quality of life (standardised mean difference (SMD) -0.12, 95% CI -0.23 to -0.01, data from three trials), patient reported cure/improvement (RR 1.25, 95% CI 1.13 to 1.39, data from two trials), leakage episodes in 24 hours (weighted mean difference (WMD) -0.30, 95% CI -0.53 to -0.08, data from four studies) and urgency episodes in 24 hours (WMD -0.43, 95% CI -0.74 to -0.13, data from four trials), all favouring solifenacin.

What the evidence does not support

The effect on quality of life is only slight and rated low certainty, and the review could not say whether any benefit lasts or survives stopping the drug. (Source 9)

• Systematic review, Low certainty.
• Size: 12 studies, 6,804 participants for the quality-of-life analysis.
• Who: Adults with overactive bladder syndrome.
• How long: End of treatment; most included trials were 12 weeks.
• Result: Condition-specific quality of life MD 4.41 lower (95% CI 5.28 lower to 3.54 lower) on a scale running -100 to 0, low-certainty evidence.
• Funding: Independent; 'none known' declared by all authors.

In addition, recent studies suggest that this is generally associated with only modest improvement in quality of life. Adverse effects were higher with all anticholinergics compared with placebo. Withdrawals due to adverse effects were also higher for all anticholinergics except tolterodine. It is not known whether any benefits of anticholinergics are sustained during long-term treatment or after treatment stops.

Safety and effectiveness of the tablet have never been established in children, so paediatric use of this formulation is off-label. (Source 3)

• Official position, Certainty not rated.
• Size: No paediatric participants in the four registration trials.
• Who: Children and adolescents.
• How long: Not applicable.
• Result: No effect estimate exists for this formulation in children.
• Funding: Not applicable.

The safety and effectiveness of solifenacin succinate tablets have not been established in pediatric patients.

The head-to-head anticholinergic review rested on trials of variable quality, and more than half of the trials that measured quality of life produced no data it could use. (Source 16)

• Systematic review, Low certainty.
• Size: 86 trials, 31,249 adults; 29 trials collected quality-of-life data but only 15 reported useable data.
• Who: Adults with overactive bladder symptoms or detrusor overactivity.
• How long: Mostly 12 weeks.
• Result: No pooled estimate for this finding; 70 trials were parallel and 16 cross-over, and the cross-over trials could not be entered into any meta-analysis.
• Funding: Independent; conflict of interest 'None declared'

Limit of this finding: The published abstract runs this passage straight into the next heading with no space after the full stop ("useable data.Tolterodine versus oxybutynin:"). That is how the source prints it. The review is also from 2012, so it predates the long-term solifenacin and mirabegron trials summarised elsewhere in this entry.

Eighty six trials, 70 parallel and 16 cross-over designs were included (31,249 adults). Most trials were described as double-blind, but were variable in other aspects of quality. Crossover studies did not present data in a way that could be included in the meta-analyses. Twenty nine collected quality of life data (the primary outcome measure) using validated measures, but only fifteen reported useable data.

The only review of trials lasting a year or more could not pool the efficacy results at all, so its efficacy comparison is a narrative summary rather than a calculated estimate. (Source 4)

• Systematic review, Low certainty.
• Size: Five randomised controlled trials, from 7,451 records screened.
• Who: Patients with overactive bladder.
• How long: At least one year.
• Result: Heterogeneity above 58% precluded pooling of the primary efficacy outcomes (volume voided, incontinence episodes per 24 h, micturition frequency per 24 h); only the safety outcomes were combined, with a random-effects model.
• Funding: Independent; authors declared no commercial or financial relationships.

Limit of this finding: The journal writes the heterogeneity statistic as "I2" where it means I-squared; that is how the record prints and it has been kept. The review's own background adds that its long-term evidence covers only solifenacin and mirabegron and that generalising it to other bladder drugs remains uncertain.

Quantitative meta-analysis was performed only for safety outcomes using a random-effects model. For the primary efficacy outcomes, substantial heterogeneity (I2>58%) across the included studies precluded meaningful pooling, therefore, a narrative synthesis of efficacy data was presented.

Where the evidence is mixed

In the only systematic review of trials lasting a year or more, heterogeneity was too great to pool efficacy at all, and the reviewers judged mirabegron the more favourable long-term option. (Source 4)

• Systematic review, Low certainty.
• Size: Five randomised controlled trials, from 7,451 records screened.
• Who: Patients with overactive bladder.
• How long: At least one year.
• Result: Versus mirabegron 50 mg, solifenacin 5 mg carried dry mouth RR 1.73 (95% CI 0.91-3.30, P = 0.10) and constipation RR 2.46 (95% CI 1.16-5.19, P = 0.02), but less dizziness RR 0.08 (95% CI 0.01-0.62, P = 0.02); efficacy could not be pooled because I2 exceeded 58%.
• Funding: Independent; authors declared no commercial or financial relationships.

Limit of this finding: The journal prints "mirabegron 50mg" and "95%CI" without spaces, and writes the heterogeneity statistic as "I2" where it means I-squared; all three are reproduced as the source prints them. More importantly, only the safety numbers in this review were pooled statistically. The efficacy comparison is a narrative summary the authors wrote because heterogeneity was too high to combine the trials, so "may be more effective" is not a pooled estimate and carries no confidence interval.

Compared to mirabegron 50mg, solifenacin 5 mg was associated with a potentially higher risk of ADRs such as dry mouth (RR 1.73, 95%CI 0.91-3.30, P = 0.10) and constipation (RR 2.46, 95%CI 1.16-5.19, P = 0.02), but a lower incidence of dizziness (RR 0.08, 95%CI 0.01-0.62, P = 0.02).

Within the 12-week trials, older patients did no worse and no better than younger ones; the trials were far too short to see the long-term cognitive outcome that observational data raise. (Source 17)

• Randomized trial, Low certainty.
• Size: 623 patients aged 65 and over, 189 aged 75 and over, and 1,188 aged under 65.
• Who: Adults in the placebo-controlled solifenacin trials.
• How long: 12 weeks.
• Result: Similar safety and effectiveness reported between geriatric and younger adult patients; no numbers are given in this section.
• Funding: Not stated in the label.

In placebo-controlled clinical studies, similar safety and effectiveness were observed between geriatric patients (623 patients ≥ 65 years and 189 patients ≥ 75 years) and younger adult patients (1188 patients < 65 years) treated with solifenacin succinate tablets.

At three times the maximum licensed dose solifenacin lengthened the QT interval by 8 msec, but the label states the confidence intervals overlapped with the positive control and the study was not designed to compare them. (Source 1)

• Randomized trial, Low certainty.
• Size: 76 healthy female volunteers; 51 took solifenacin 10, 20 and 30 mg sequentially and 25 took placebo and moxifloxacin in parallel.
• Who: Healthy female volunteers aged 19 to 79 years.
• How long: Sequential dose-escalation; baseline ECGs were separated from the final 30 mg assessment by 33 days.
• Result: Table 2, QTc change in msec (90% CI) from baseline at Tmax relative to placebo by the Fridericia method: solifenacin 10 mg 2 (-3,6); solifenacin 30 mg 8 (4,13). The moxifloxacin positive control gave 11 (7, 14), 12 (8, 17) and 16 (12, 21) in three sessions. Median heart-rate difference from baseline versus placebo was -2 beats/minute at 10 mg and 0 at 30 mg.
• Funding: Not stated in the label.

Limit of this finding: At the licensed 10 mg dose the central estimate was 2 msec with a 90% confidence interval running from -3 to 6, so an effect of zero is inside the interval. The restored block also carries the label's footnote markers, which the label prints as superscripts and this rendering flattens into the digits at the start of "1Results displayed" and "2 Moxifloxacin"; those digits are footnote numbers, not values.

However, the confidence intervals overlapped, and this study was not designed to draw direct statistical conclusions between the drugs or the dose levels.

Where the research disagrees

Whether long-term use of solifenacin raises the risk of dementia

• Iyen and colleagues, BMJ Medicine 2024, Nested case-control study in routine primary-care records; an association, adjusted for recorded confounders, and incapable of proving cause: The adjusted odds ratio for dementia associated with the use of any anticholinergic drug used to treat an overactive bladder was 1.18 (95% confidence interval (CI) 1.16 to 1.20), and was higher in men (1.22, 1.18 to 1.26) than women (1.16, 1.13 to 1.19). (Source 8)
• Stoniute and colleagues, Cochrane 2023, Systematic review of 104 randomised placebo-controlled trials, almost all 12 weeks long, which neither measured nor could have measured dementia over years: It is not known whether any benefits of anticholinergics are sustained during long-term treatment or after treatment stops. (Source 9)

Whether solifenacin or the beta-3 agonist mirabegron is the better long-term choice

• Madhuvrata and colleagues, Cochrane 2012, Systematic review of 86 head-to-head anticholinergic trials, which found solifenacin favourable against immediate-release tolterodine but did not examine beta-3 agonists: Different doses of solifenacin: The standard recommended starting dose of 5 mg once daily was compared to 10 mg: while frequency and urgency were less (better) with 10 mg compared to 5 mg, there was a higher risk of dry mouth with 10 mg solifenacin at four to 12 weeks. (Source 16)
• Yang and colleagues, Frontiers in Pharmacology 2026, Systematic review of five trials of at least a year; safety meta-analysed, efficacy only narratively synthesised because heterogeneity exceeded 58%: For long-term OAB pharmacotherapy with the specific regimens evaluated, mirabegron 50 mg appears to offer a favorable profile due to its comparable efficacy and lower incidence of certain treatment-limiting ADRs. (Source 4)

How much

• Reference intake: There is no reference intake for a prescription medicine; the dose is set by the prescriber. The US label states, as a position dated to SPL version 2 effective 22 September 2026, that the recommended oral dose is 5 mg once daily, which may be raised to 10 mg once daily if 5 mg is well tolerated, taken with water and swallowed whole, with or without food. (Source 18)
• Upper limit: No upper limit is set by a nutrition body. The label's maximum, as a regulatory position, is 10 mg once daily, reduced to a 5 mg ceiling in severe renal impairment (CLcr < 30 mL/min/1.73 m2), in moderate hepatic impairment (Child-Pugh B) and when a strong CYP3A4 inhibitor is taken; it is not to be used at all in severe hepatic impairment (Child-Pugh C). (Source 18)
• Studied: The four 12-week registration trials gave 5 mg or 10 mg once daily; two trials tested both doses and two tested 10 mg only, with an open-label 40-week extension. (Source 15)
• Studied: The cardiac study gave 10, 20 and 30 mg sequentially to 51 female volunteers, with 30 mg chosen because it reproduces the exposure seen when 10 mg is combined with a strong CYP3A4 inhibitor. (Source 1)
• Studied: In healthy volunteers taking 50 mg daily, five times the maximum recommended dose, intolerable antimuscarinic effects appeared on day 3 and resolved within 7 days of stopping; the largest accidental overdose reported was 280 mg in 5 hours. (Source 19)

A common belief, and what the research shows

The belief: An overactive bladder tablet stops the leaking and the rushing to the toilet.

What the research shows: The registration trials measured how much better than placebo it is, and the gap is about one event a day. Voids fell by 2.7 per 24 hours on 10 mg against 1.4 on placebo, and leaks by 1.8 against 1.1, so roughly 1.3 fewer voids and 0.7 fewer leaks are attributable to the drug: "The mean reduction in the number of incontinence episodes per 24 hours was significantly greater with solifenacin succinate tablets 5 mg (1.5; p < 0.001) and solifenacin succinate tablets 10 mg (1.8; p < 0.001) treatment groups compared to the placebo treatment group (1.1)." The class review reaches the same place: "The use of anticholinergic drugs by people with overactive bladder syndrome results in important but modest improvements in symptoms compared with placebo treatment."

Questions and answers

What is it?

Solifenacin succinate is a prescription tablet taken once a day for the symptoms of an overactive bladder. It is a muscarinic receptor blocker, one of the group of medicines often called anticholinergics or antimuscarinics. It comes as 5 mg and 10 mg film-coated tablets. It is a manufactured medicine, not a nutrient, and does not occur in food. (Source 2)

What does it do in the body?

Nerves normally release acetylcholine onto muscarinic receptors on the bladder's muscle wall to make it squeeze. Solifenacin competes for those receptors, so the bladder squeezes less and tolerates more urine before signalling urgency. The same receptors are present in the salivary glands, bowel, eyes and brain, so the same action also dries the mouth, slows the bowel, blurs vision and, in some people, clouds thinking. (Source 1)

Is it good or bad for you?

It helps, modestly, and it has a price. For an adult with genuine overactive bladder the trials show about one fewer void and about half to three-quarters of a leak less per day than placebo. Against that, dry mouth reached 27.6% on 10 mg compared with 4.2% on placebo, constipation 13.4% versus 2.9%, and urinary retention 1.4% versus 0.6%. It is the wrong drug for someone who already cannot empty their bladder or stomach, or who has uncontrolled narrow-angle glaucoma, and the drying effects and the dementia association both grow with cumulative dose, which matters most in older people. (Source 9)

How do you get more of it?

Solifenacin can only be obtained on prescription; there is no food, supplement or behaviour that supplies it. The doses studied in the four 12-week trials were 5 mg and 10 mg once daily, and the label's position is that 5 mg is the starting dose and may be raised to 10 mg if tolerated. Taking it with a strong CYP3A4-blocking medicine raises blood levels of the same tablet, which is why the label caps the dose at 5 mg in that situation. None of this is a recommendation for any reader. (Source 18)

If it is harmful, what reduces it?

When the drug's antimuscarinic effects are the problem, the documented responses are lowering the dose or stopping it; the label says so for central nervous system effects. There is no antidote and no supplement that clears it. After an overdose the label describes gastric lavage, supportive measures and ECG monitoring, and notes that volunteers taking five times the maximum dose recovered within 7 days of stopping. Because the half-life is 45 to 68 hours, washout takes days rather than hours. (Source 19)

Why might someone be low in it or missing it?

This question does not apply in the usual sense: solifenacin is not made by the body, so no one is deficient in it. Someone may not be on it because they do not have overactive bladder, because it is contraindicated for them, or because the dose must be restricted. The label bars it in urinary retention, gastric retention and uncontrolled narrow-angle glaucoma, and caps or forbids it in severe kidney impairment, moderate or severe liver impairment, and alongside strong CYP3A4 inhibitors. (Source 18)

Which whole foods contain it or feed it?

No whole food contains solifenacin and no food feeds it; it is a synthetic medicine. Food barely affects how much gets absorbed either: a 10 mg dose taken with a meal raised peak blood level by 4% and total exposure by 3%, which is why the label says it may be taken without regard to meals. The label records no interaction with grapefruit juice or with any dietary supplement. (Source 6)

What happens if you do not have it?

Nothing happens from lacking the drug itself; what persists is the condition. Overactive bladder affects around 16% of adults and becomes commoner with age, and in the placebo arms of the trials symptoms improved only slightly on their own, by about 1.4 fewer voids and 1.1 fewer leaks per 24 hours. Someone not taking any treatment keeps the urgency, frequency and leakage the drug would have reduced by roughly one event a day. (Source 20)

How can you test for it?

There is no blood test for solifenacin in ordinary care and no target blood level to aim at. What the trials measured instead was a bladder diary: the number of voids per 24 hours as the primary endpoint, with leakage episodes per 24 hours and volume passed each time as secondary endpoints. That diary is the practical test of whether the drug is working for a given person. Kidney and liver function matter because they set the dose ceiling, and the label advises ECG monitoring after overdose. (Source 15)

References

1. DailyMed (U.S. National Library of Medicine), Structured Product Label. Solifenacin Succinate Tablets, Section 12 CLINICAL PHARMACOLOGY / 12.1 Mechanism of Action and 12.2 Pharmacodynamics (Macleods Pharmaceuticals Limited). SPL version 2, effective 2026-09-22 (label marked "Revised: March 2024"). Read the source
2. DailyMed (U.S. National Library of Medicine), Structured Product Label. Solifenacin Succinate Tablets, Section 1 INDICATIONS & USAGE (Macleods Pharmaceuticals Limited). SPL version 2, effective 2026-09-22 (label marked "Revised: March 2024"). Read the source
3. DailyMed (U.S. National Library of Medicine), Structured Product Label. Solifenacin Succinate Tablets, Section 8.4 Pediatric Use (Macleods Pharmaceuticals Limited). SPL version 2, effective 2026-09-22 (label marked "Revised: March 2024"). Read the source
4. Frontiers in Pharmacology. Long-term efficacy and safety of solifenacin, mirabegron, and their combination for overactive bladder: a systematic review. 2026. PMID 42403713, DOI 10.3389/fphar.2026.1874436. Read the source
5. DailyMed (U.S. National Library of Medicine), Structured Product Label. Solifenacin Succinate Tablets, Section 7 DRUG INTERACTIONS / 7.1 Strong CYP3A4 Inhibitors (Macleods Pharmaceuticals Limited). SPL version 2, effective 2026-09-22 (label marked "Revised: March 2024"). Read the source
6. DailyMed (U.S. National Library of Medicine), Structured Product Label. Solifenacin Succinate Tablets, Section 12.3 Pharmacokinetics (Macleods Pharmaceuticals Limited). SPL version 2, effective 2026-09-22 (label marked "Revised: March 2024"). Read the source
7. DailyMed (U.S. National Library of Medicine), Structured Product Label. Solifenacin Succinate Tablets, Section 5.6 QT Prolongation in Patients at High Risk of QT Prolongation (Macleods Pharmaceuticals Limited). SPL version 2, effective 2026-09-22 (label marked "Revised: March 2024"). Read the source
8. BMJ Medicine. Risk of dementia associated with anticholinergic drugs for overactive bladder in adults aged ≥55 years: nested case-control study. 2024. PMID 39574420, DOI 10.1136/bmjmed-2023-000799. Read the source
9. Cochrane Database of Systematic Reviews. Oral anticholinergic drugs versus placebo or no treatment for managing overactive bladder syndrome in adults (Authors’ conclusions). 2023. PMID 37160401, DOI 10.1002/14651858.CD003781.pub3. Read the source
10. DailyMed (U.S. National Library of Medicine), Structured Product Label. Solifenacin Succinate Tablets, Section 6.1 Clinical Trials Experience, with Table 1 (Macleods Pharmaceuticals Limited). SPL version 2, effective 2026-09-22 (label marked "Revised: March 2024"). Read the source
11. DailyMed (U.S. National Library of Medicine), Structured Product Label. Solifenacin Succinate Tablets, Section 5.4 Central Nervous System Effects (Macleods Pharmaceuticals Limited). SPL version 2, effective 2026-09-22 (label marked "Revised: March 2024"). Read the source
12. Cochrane Database of Systematic Reviews. Oral anticholinergic drugs versus placebo or no treatment for managing overactive bladder syndrome in adults. 2023. PMID 37160401, DOI 10.1002/14651858.CD003781.pub3. Read the source
13. DailyMed (U.S. National Library of Medicine), Structured Product Label. Solifenacin Succinate Tablets, Section 6.2 Postmarketing Experience (Macleods Pharmaceuticals Limited). SPL version 2, effective 2026-09-22 (label marked "Revised: March 2024"). Read the source
14. DailyMed (U.S. National Library of Medicine), Structured Product Label. Solifenacin Succinate Tablets, Section 4 CONTRAINDICATIONS (Macleods Pharmaceuticals Limited). SPL version 2, effective 2026-09-22 (label marked "Revised: March 2024"). Read the source
15. DailyMed (U.S. National Library of Medicine), Structured Product Label. Solifenacin Succinate Tablets, Section 14 CLINICAL STUDIES (Macleods Pharmaceuticals Limited). SPL version 2, effective 2026-09-22 (label marked "Revised: March 2024"). Read the source
16. Cochrane Database of Systematic Reviews. Which anticholinergic drug for overactive bladder symptoms in adults. 2012. PMID 22258963, DOI 10.1002/14651858.CD005429.pub2. Read the source
17. DailyMed (U.S. National Library of Medicine), Structured Product Label. Solifenacin Succinate Tablets, Section 8.5 Geriatric Use (Macleods Pharmaceuticals Limited). SPL version 2, effective 2026-09-22 (label marked "Revised: March 2024"). Read the source
18. DailyMed (U.S. National Library of Medicine), Structured Product Label. Solifenacin Succinate Tablets, Section 2 DOSAGE & ADMINISTRATION (Macleods Pharmaceuticals Limited). SPL version 2, effective 2026-09-22 (label marked "Revised: March 2024"). Read the source
19. DailyMed (U.S. National Library of Medicine), Structured Product Label. Solifenacin Succinate Tablets, Section 10 OVERDOSAGE (Macleods Pharmaceuticals Limited). SPL version 2, effective 2026-09-22 (label marked "Revised: March 2024"). Read the source
20. Cochrane Database of Systematic Reviews. Oral anticholinergic drugs versus placebo or no treatment for managing overactive bladder syndrome in adults (Background and Objectives). 2023. PMID 37160401, DOI 10.1002/14651858.CD003781.pub3. Read the source