Clindamycin

What it is

Clindamycin is a prescription-only lincosamide antibacterial, given by mouth, by injection, or applied to the skin or vagina. The oral capsule form is clindamycin hydrochloride; topical and injectable products use clindamycin phosphate. The U.S. label restricts it to serious infections caused by susceptible bacteria, and says the oral capsules should be reserved for people allergic to penicillin or for whom a penicillin is unsuitable.

What the research says

The evidence is strongest for short courses in bacterial skin and soft-tissue infection, where a placebo-controlled randomised trial showed it raised cure after abscess drainage, and for topical fixed-combination treatment of acne. It is not more effective than trimethoprim-sulfamethoxazole for uncomplicated skin infection. Against that, clindamycin carries a boxed warning for Clostridioides difficile infection, and it is the antibiotic most strongly associated with C. difficile in observational meta-analyses and the one with the highest reported rate of fatal adverse reactions in dental prescribing data.

Evidence grade: Well established.

How it works

Drug class: Lincosamide antibacterial (bacterial protein synthesis inhibitor acting at the 50S ribosomal subunit)

Clindamycin sticks to part of the bacterial ribosome, the machine bacteria use to build proteins, and stops that machine working. At usual concentrations it holds bacteria in check rather than killing them outright. (Source 1)

Boxed warning

Clostridioides difficile infection (CDI) has been reported with use of nearly all antibacterial agents, including CLEOCIN HCl and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon, leading to overgrowth of C. difficile.

(Source 2)

What it is used for

• This is the use the U.S. label is built around, and the label itself says the drug should be kept for serious infections where less toxic agents are inappropriate. Comparative outcome trials in this specific population are old and sparse; most modern randomised evidence is in skin and soft-tissue infection. Evidence: established. (Source 3)
• In a placebo-controlled randomised trial of 786 people with abscesses 5 cm or smaller, cure 10 days after treatment was 83.1% with clindamycin versus 68.9% with placebo, an absolute difference of about 14 percentage points. In a separate randomised trial of 524 people it was no better than trimethoprim-sulfamethoxazole. Evidence: established. (Source 4)
• A 741-participant randomised phase II trial of a fixed clindamycin phosphate 1.2% / benzoyl peroxide 3.1% / adapalene 0.15% gel reported treatment success in 52.5% at 12 weeks versus 8.1% on vehicle. The trial cannot separate out how much of that came from the clindamycin component, and the two-drug combinations containing clindamycin reached only 27.8-30.5%. Evidence: established. (Source 5)
• Widely used off-label on the theory that clindamycin suppresses streptococcal exotoxin production. The supporting human evidence is observational, not randomised, and rising clindamycin resistance in group A Streptococcus in the United States complicates it. Evidence: limited. (Source 6)
• Analyses of English national prescribing and pharmacovigilance data found single-dose clindamycin prophylaxis carried 13 fatal and 149 non-fatal reported reactions per million prescriptions, mostly C. difficile infections, versus no fatal reactions in nearly 3 million amoxicillin prescriptions. These are spontaneous-reporting rates, which under-count events and cannot establish causation on their own. Evidence: disputed. (Source 7)

Interactions

• Neuromuscular blocking agents (used in anaesthesia) (label): Clindamycin has neuromuscular blocking properties of its own and can deepen the effect of these drugs. (Source 8)
• Strong CYP3A4 inhibitors and inducers, including rifampicin (pharmacokinetic study): Clindamycin is broken down mainly by the CYP3A4 enzyme, so drugs that block that enzyme raise clindamycin levels and drugs that speed it up lower them. This is the mechanism by which enzyme-inducing herbal products such as St John's wort would be expected to reduce clindamycin levels, though no clindamycin-specific study of that was found. (Source 8)
• Water and body position when swallowing the capsule (label): Taking the capsule with too little water, or lying down soon after, has been linked to inflammation and ulceration of the oesophagus. The label instructs a full glass of water and staying upright for at least 30 minutes. (Source 9)
• Probiotic supplements (Lactobacillus rhamnosus, Saccharomyces boulardii and others) (clinical trial): Not a harmful interaction: in children taking any antibiotic, probiotics roughly halved antibiotic-associated diarrhoea on moderate-quality evidence. The review was not clindamycin-specific, and it warns that serious events have occurred in severely debilitated or immunocompromised children. (Source 10)
• Yeasts and other organisms clindamycin does not kill (label): Because clindamycin clears out much of the normal bacterial population, organisms it does not act on, especially yeasts, can overgrow. (Source 11)

Stopping it

• There is no taper and no withdrawal syndrome for clindamycin; the clinically important instruction runs the other way. The label says the drug should be stopped if significant diarrhoea develops during treatment. (Source 9)
• Diarrhoea caused by an antibiotic usually settles once the antibiotic is stopped, but C. difficile colitis can appear as late as two months after the last dose, so stopping the drug does not end the risk window. (Source 12)
• If C. difficile infection is suspected or confirmed, the boxed warning states that antibacterial treatment not aimed at C. difficile may need to be discontinued, alongside fluid and electrolyte management and surgical assessment. (Source 2)

What goes wrong

The U.S. label carries a boxed warning that Clostridioides difficile infection has been reported with clindamycin and may range from mild diarrhoea to fatal colitis, and that the drug should be reserved for serious infections. (Source 2)

• Official position, Certainty not rated.
• Size: not applicable.
• Who: People prescribed clindamycin hydrochloride capsules.
• How long: not applicable.
• Result: No rate is given in the boxed warning itself; it is a regulatory position stated on the label dated 16 September 2026.
• Funding: not stated.

Clostridioides difficile infection (CDI) has been reported with use of nearly all antibacterial agents, including CLEOCIN HCl and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon, leading to overgrowth of C. difficile.

In a meta-analysis of community (non-hospitalised) populations, clindamycin exposure carried the largest association with C. difficile infection of any antibiotic class examined, an odds ratio of 16.80 against no antibiotic exposure. (Source 13)

• Meta-analysis, Low certainty.
• Size: 7 included studies, all observational, from 465 screened articles.
• Who: Non-hospitalised people in the community.
• How long: exposure windows varied between the included studies.
• Result: Clindamycin OR 16.80, 95% CI 7.48 to 37.76; fluoroquinolones OR 5.50 (4.26 to 7.11); cephalosporins/monobactams/carbapenems OR 5.68 (2.12 to 15.23); tetracyclines OR 0.92 (0.61 to 1.40)
• Funding: independent (Canadian Institutes of Health Research)

Five studies considered antibiotic risk relative to no antibiotic exposure: clindamycin (OR = 16.80; 95% confidence interval [95% CI], 7.48 to 37.76), fluoroquinolones (OR = 5.50; 95% CI, 4.26 to 7.11), and cephalosporins, monobactams, and carbapenems (CMCs) (OR = 5.68; 95% CI, 2.12 to 15.23) had the largest effects, while macrolides (OR = 2.65; 95% CI, 1.92 to 3.64), sulfonamides and trimethoprim (OR = 1.81; 95% CI, 1.34 to 2.43), and penicillins (OR = 2.71; 95% CI, 1.75 to 4.21) had lower associations with CDI.

In hospital-acquired C. difficile infection, clindamycin was the second strongest association found, an odds ratio of 2.86; this is an association from case-control and cohort studies, not a causal estimate from randomised trials. (Source 14)

• Systematic review, Low certainty.
• Size: 13 case-control studies and 1 cohort study, 15,938 patients.
• Who: Hospital inpatients.
• How long: timing of antibiotic exposure measurement varied and was a stated source of heterogeneity.
• Result: Clindamycin OR 2.86, 95% CI 2.04 to 4.02, 6 studies, I(2) = 28.5%; third-generation cephalosporins OR 3.20 (1.80 to 5.71)
• Funding: not stated.

The strongest associations were found for third-generation cephalosporins (OR = 3.20, 95% CI = 1.80-5.71; n = 6 studies; I(2) = 79.2%), clindamycin (2.86, 2.04-4.02; n = 6; I(2) = 28.5%)

In English national dental prescribing and pharmacovigilance data, clindamycin had the highest reported rate of fatal and of overall adverse drug reactions of any commonly prescribed dental antibiotic, driven by C. difficile infection. (Source 15)

• Survey study, Low certainty.
• Size: NHS prescribing and Yellow Card reports for England, 2010 to 2017.
• Who: People given oral antibiotics by dentists in England.
• How long: 8 years of national data.
• Result: Clindamycin 2.9 fatal and 337.3 overall reported adverse drug reactions per million prescriptions, versus amoxicillin 0.1 fatal and 21.5 overall per million.
• Funding: independent (NIAID NIH, NCEZID CDC, NCATS NIH acknowledged)

Limit of this finding: The paper misspells the organism: it prints "Clostridiodes (formerly Clostridium) difficile" where the correct name is Clostridioides difficile. The misspelling is the journal's and is quoted as printed; it does not affect the reported rates. Note also that these are spontaneously reported adverse reactions counted against prescription numbers, so they show an association with clindamycin prescribing, not a measured rate of harm in a defined group of patients.

In contrast, clindamycin, which is often used in patients with penicillin allergy, had the highest rate of fatal (2.9/million prescriptions) and overall (337.3/million prescriptions) ADRs, with Clostridiodes (formerly Clostridium) difficile infections pivotal to its ADR profile.

A single 600 mg prophylactic dose of clindamycin was associated with 13 fatal and 149 non-fatal reported reactions per million prescriptions, mostly C. difficile infections, while amoxicillin prophylaxis had no fatal reports in nearly 3 million prescriptions. (Source 7)

• Survey study, Low certainty.
• Size: English NHS prophylaxis prescribing January 2004 to March 2014 with MHRA Yellow Card reports.
• Who: People given single-dose antibiotic prophylaxis before invasive dental procedures.
• How long: just over 10 years of national data.
• Result: Clindamycin 13 fatal and 149 non-fatal reactions per million prescriptions; amoxicillin 0 fatal and 22.62 non-fatal per million.
• Funding: independent (NIDCR NIH and UK National Institute for Health Research)

For clindamycin, it was 13 fatal and 149 non-fatal reactions/million prescriptions. Most clindamycin adverse drug reactions were Clostridium difficile infections.

In the placebo-controlled abscess trial, adverse events were about twice as common on clindamycin as on placebo, though all resolved without lasting harm. (Source 4)

• Randomized trial, High certainty.
• Size: 781 participants with adverse-event data (265 clindamycin, 261 TMP-SMX, 255 placebo)
• Who: Outpatient adults and children with a drained skin abscess 5 cm or smaller.
• How long: 10 days of treatment with 1 month follow-up.
• Result: Adverse events 21.9% (58/265) on clindamycin vs 12.5% (32/255) on placebo and 11.1% (29/261) on TMP-SMX, an absolute excess of about 9 percentage points over placebo (roughly 1 extra adverse event per 11 treated)
• Funding: independent (National Institutes of Health)

Adverse events were more frequent with clindamycin (58 of 265 [21.9%]) than with TMP-SMX (29 of 261 [11.1%]) or placebo (32 of 255 [12.5%]); all adverse events resolved without sequelae.

Clindamycin capsules have caused oesophagitis and oesophageal ulcer, particularly when swallowed lying down or with little water. (Source 16)

• Case series, Very low certainty.
• Size: not stated (spontaneous reports collected on the label)
• Who: People taking clindamycin hydrochloride capsules.
• How long: not stated.
• Result: No rate is given; the label reports these as adverse reactions with a stated positional and fluid-volume risk factor.
• Funding: not stated.

Esophagitis (including necrotizing esophagitis) and esophageal ulcer have been reported, particularly when taken in a lying position or with a small amount of water.

The U.S. label records severe skin reactions with clindamycin, including toxic epidermal necrolysis with some fatal outcomes, as well as anaphylactic shock and other severe hypersensitivity reactions. (Source 16)

• Case series, Very low certainty.
• Size: Postmarketing reports; no denominator is given on the label.
• Who: People given oral clindamycin.
• How long: Not stated.
• Result: No rate is given. The label lists toxic epidermal necrolysis (some fatal), acute generalized exanthematous pustulosis, erythema multiforme including presentations resembling Stevens-Johnson syndrome, anaphylactic shock and anaphylactic reaction.
• Funding: not stated (manufacturer label text)

Vesiculobullous rashes, as well as urticaria, have been observed during drug therapy. Severe skin reactions such as toxic epidermal necrolysis, some with fatal outcome, have been reported (See WARNINGS ).

What the evidence supports

Adding clindamycin to incision and drainage of a small skin abscess raised the 10-day cure rate from 68.9% on placebo to 83.1%, an absolute gain of about 14 percentage points (roughly 7 people treated for one extra cure). (Source 4)

• Randomized trial, High certainty.
• Size: 786 participants (505 adults, 281 children)
• Who: Outpatient adults and children with a drained skin abscess 5 cm or smaller; MRSA isolated from 49.4%.
• How long: 10 days of treatment, outcome 7 to 10 days after treatment ended.
• Result: Clindamycin 83.1% (221/266) vs TMP-SMX 81.7% (215/263), P=0.73; both higher than placebo 68.9% (177/257), P<0.001 for both comparisons.
• Funding: independent (funded by the National Institutes of Health)

the cure rate among participants in the clindamycin group was similar to that in the TMP-SMX group (221 of 266 participants [83.1%] and 215 of 263 participants [81.7%], respectively; P=0.73), and the cure rate in each active-treatment group was higher than that in the placebo group (177 of 257 participants [68.9%], P<0.001 for both comparisons)

A fixed topical gel containing clindamycin phosphate 1.2% with benzoyl peroxide and adapalene produced treatment success in 52.5% at 12 weeks versus 8.1% on vehicle, but the clindamycin-containing two-drug combinations reached only 27.8-30.5%, so the trial cannot attribute the effect to clindamycin alone. (Source 5)

• Randomized trial, Moderate certainty.
• Size: 741 participants.
• Who: People aged 9 years and older with moderate-to-severe acne.
• How long: 12 weeks.
• Result: Treatment success 52.5% with the triple combination vs 8.1% vehicle and 27.8-30.5% for the dyads, P ≤ 0.001 for all comparisons; absolute lesion reductions 29.9 inflammatory and 35.5 non-inflammatory versus 19.6-26.8 and 21.8-30.0 for vehicle or dyads, P < 0.05 for all.
• Funding: not stated in the record retrieved (an industry-developed fixed-combination product)

At week 12, 52.5% of participants achieved treatment success with IDP-126 vs vehicle (8.1%) and dyads (range 27.8-30.5%; P ≤ 0.001, all). IDP-126 also provided significantly greater absolute reductions in inflammatory (29.9) and noninflammatory (35.5) lesions compared with vehicle or dyads (range inflammatory, 19.6-26.8; noninflammatory, 21.8-30.0; P < 0.05, all), corresponding to > 70% reductions with IDP-126.

Antibiotic-associated diarrhoea, the commonest problem with clindamycin, is itself reducible: in children on any antibiotic, probiotics cut it from 19% to 8%, a number needed to treat of about 10 on moderate-quality evidence. (Source 17)

• Systematic review, Moderate certainty.
• Size: 23 studies, 3,938 participants.
• Who: Children aged 0 to 18 years receiving antibiotics (not clindamycin-specific)
• How long: duration of the antibiotic course plus follow-up.
• Result: Antibiotic-associated diarrhoea 8% (163/1992) on probiotics vs 19% (364/1906) on control, RR 0.46, 95% CI 0.35 to 0.61, I(2) = 55%; NNT about 10. The review's own extreme-plausible sensitivity analysis, which assumes most children lost to follow-up in the probiotic arm had diarrhoea, gives the more conservative 14% (330/2294) vs 19% (426/2235), RR 0.69, 95% CI 0.54 to 0.89, I(2) = 63%.
• Funding: not stated.

Limit of this finding: The headline 46 percent relative reduction comes from the trials as reported. The review also ran a deliberately pessimistic sensitivity analysis to test what missing children could do to the result, and that gives a smaller reduction, from 19 percent to 14 percent. Both figures are the review's own, and the smaller one is the safer number to carry in your head.

The incidence of AAD in the probiotic group was 8% (163/1992) compared to 19% (364/1906) in the control group (RR 0.46, 95% CI 0.35 to 0.61; I(2) = 55%, 3898 participants). A GRADE analysis indicated that the overall quality of the evidence for this outcome was moderate.

What the evidence does not support

In uncomplicated skin infection, clindamycin was not more effective than trimethoprim-sulfamethoxazole; the difference in cure was -2.6 percentage points with a confidence interval spanning no difference. (Source 18)

• Randomized trial, High certainty.
• Size: 524 patients (264 clindamycin, 260 TMP-SMX), including 155 children.
• Who: Outpatients with cellulitis, abscesses larger than 5 cm, or both.
• How long: 10 days of treatment.
• Result: Intention-to-treat cure 80.3% vs 77.7%; difference -2.6 percentage points, 95% CI -10.2 to 4.9, P=0.52; evaluable population 89.5% vs 88.2%, difference -1.2 points, 95% CI -7.6 to 5.1, P=0.77.
• Funding: independent (National Institute of Allergy and Infectious Diseases and NCATS, NIH)

The proportion of patients cured was similar in the two treatment groups in the intention-to-treat population (80.3% in the clindamycin group and 77.7% in the TMP-SMX group; difference, -2.6 percentage points; 95% confidence interval [CI], -10.2 to 4.9; P=0.52)

Where the evidence is mixed

The claim that adjunctive clindamycin reduces death in invasive group A streptococcal infection rests on laboratory, animal and observational human data rather than randomised trials, and clindamycin resistance in these bacteria has been rising. (Source 6)

• Expert review, not systematic, Very low certainty.
• Size: not stated (a structured pro-con debate reviewing existing studies)
• Who: People with group A streptococcal necrotising soft tissue infection or toxic shock syndrome.
• How long: not applicable.
• Result: No pooled effect estimate is given; the authors describe the supporting human evidence as observational.
• Funding: not stated.

In vitro and animal model data, as well as multiple observational studies, suggest adjunctive clindamycin (ie, given with a beta-lactam) reduces invasive GAS infection mortality by inhibiting exotoxin production.

Clindamycin resistance arises from changes to the bacterial 23S ribosomal RNA, cross-resistance with lincomycin is complete, and cross-resistance is sometimes seen with macrolides and streptogramin B, so a macrolide-resistant isolate may not respond. (Source 19)

• Official position, Certainty not rated.
• Size: Not applicable (microbiology section of the U.S. label)
• Who: Bacterial isolates.
• How long: Not applicable.
• Result: No numbers are given; the label directs that macrolide-resistant staphylococci and beta-haemolytic streptococci be screened with the D-zone test for inducible clindamycin resistance.
• Funding: not stated (manufacturer label text)

Resistance to clindamycin is most often caused by modification of specific bases of the 23S ribosomal RNA. Cross-resistance between clindamycin and lincomycin is complete. Because the binding sites for these antibacterial drugs overlap, cross-resistance is sometimes observed among lincosamides, macrolides and streptogramin B.

Where the research disagrees

How large clindamycin's C. difficile risk really is, and therefore how far it should be avoided

• Brown and colleagues, meta-analysis of community-associated C. difficile infection (2013), meta-analysis of 7 observational studies: Five studies considered antibiotic risk relative to no antibiotic exposure: clindamycin (OR = 16.80; 95% confidence interval [95% CI], 7.48 to 37.76) (Source 13)
• Slimings and Riley, updated systematic review of hospital-acquired C. difficile infection (2014), systematic review and meta-analysis of 13 case-control and 1 cohort study: The strongest associations were found for third-generation cephalosporins (OR = 3.20, 95% CI = 1.80-5.71; n = 6 studies; I(2) = 79.2%), clindamycin (2.86, 2.04-4.02; n = 6; I(2) = 28.5%) (Source 14)

Whether adjunctive clindamycin should still be the default anti-toxin agent in invasive group A streptococcal infection

• Authors of a Clinical Infectious Diseases pro-con debate (2023), pro-clindamycin position, narrative review of in-vitro, animal and observational studies: In vitro and animal model data, as well as multiple observational studies, suggest adjunctive clindamycin (ie, given with a beta-lactam) reduces invasive GAS infection mortality by inhibiting exotoxin production. (Source 6)
• Same debate, the counter-position on resistance, narrative review of surveillance data: Unfortunately, clindamycin resistance in GAS has been rapidly increasing in the United States since the mid-2010s, although the clinical significance of this remains unclear. (Source 6)

How much

• Reference intake: There is no reference intake for an antibiotic. The dose is set by the prescriber. As a position, the U.S. label dated 16 September 2026 states an adult oral range of 150 to 300 mg every six hours for serious infections and 300 to 450 mg every six hours for more severe infections, and for children able to swallow capsules 8 to 16 mg/kg/day for serious infections and 16 to 20 mg/kg/day for more severe infections, each divided into three or four equal doses. (Source 9)
• Upper limit: No tolerable upper intake level exists for a prescription antibiotic. The highest oral range stated on the U.S. label dated 16 September 2026 is 300 to 450 mg every six hours for more severe infections. (Source 9)
• Studied: The placebo-controlled abscess trial gave clindamycin, trimethoprim-sulfamethoxazole or placebo for 10 days after incision and drainage. (Source 20)
• Studied: The head-to-head skin infection trial randomised patients 1:1 to clindamycin or trimethoprim-sulfamethoxazole for 10 days, double-blind. (Source 21)
• Studied: The acne trial used a once-daily fixed gel of clindamycin phosphate 1.2% with benzoyl peroxide 3.1% and adapalene 0.15%, against vehicle and against two-drug combinations. (Source 22)

A common belief, and what the research shows

The belief: Clindamycin is a good general-purpose antibiotic for sore throats, coughs and other everyday infections, especially if you are allergic to penicillin.

What the research shows: The U.S. label restricts it and says explicitly, "It should not be used in patients with nonbacterial infections such as most upper respiratory tract infections." In English dental prescribing data it had the highest reported rate of fatal reactions of any common dental antibiotic: "In contrast, clindamycin, which is often used in patients with penicillin allergy, had the highest rate of fatal (2.9/million prescriptions) and overall (337.3/million prescriptions) ADRs, with Clostridiodes (formerly Clostridium) difficile infections pivotal to its ADR profile."

Questions and answers

What is it?

Clindamycin is a prescription lincosamide antibiotic. The capsule you swallow is clindamycin hydrochloride; creams, gels, vaginal preparations and injections use clindamycin phosphate. It works against many anaerobic bacteria and against some streptococci, pneumococci and staphylococci, and the label limits it to serious infections caused by bacteria known or strongly suspected to be susceptible. (Source 3)

What does it do in the body?

It binds to the 23S RNA of the 50S part of the bacterial ribosome and blocks protein manufacture. At the concentrations reached in the body it is bacteriostatic, meaning it stops bacteria multiplying rather than killing them directly, and leaves the immune system to clear the infection. (Source 1)

Is it good or bad for you?

It depends entirely on the setting. For a drained skin abscess, a 10-day course raised cure from 68.9% to 83.1% in a randomised placebo-controlled trial. For a sore throat or a cold it is both useless and dangerous: the label says it should not be used for non-bacterial infections, and it is the antibiotic most strongly linked to C. difficile colitis, with a boxed warning saying that colitis can be fatal. (Source 2)

How do you get more of it?

Clindamycin is a prescription medicine, not a nutrient, so the only way to take it is for a prescriber to decide it is needed and set the dose. As a position, the U.S. label dated 16 September 2026 states 150 to 300 mg every six hours for serious infections in adults and 300 to 450 mg every six hours for more severe ones, and for children who can swallow capsules 8 to 16 mg/kg/day for serious infections and 16 to 20 mg/kg/day for more severe ones, divided into three or four equal doses. No figure here is advice for any individual. (Source 9)

If it is harmful, what reduces it?

Clindamycin is cleared by the body within hours of the last dose, so clearing the drug itself is not the issue. What matters is the damage to gut bacteria that it leaves behind. The label instructs stopping the drug if significant diarrhoea develops, and the Cochrane review of probiotics in children on antibiotics found antibiotic-associated diarrhoea fell from 19% to 8% with probiotics, number needed to treat about 10, on moderate-quality evidence. (Source 10)

Why might someone be low in it or missing it?

Clindamycin is not something a person can be deficient in. Blood levels can be lower than intended if another drug or product speeds up the CYP3A4 enzyme that breaks it down; the label names rifampicin as a strong inducer and says to watch for loss of effectiveness in that situation. Levels can also be lower than intended if doses are skipped or the course is not finished. (Source 8)

Which whole foods contain it or feed it?

No whole food contains clindamycin; it is a semi-synthetic antibiotic made from lincomycin and is available only on prescription. What food and drink do affect is how the capsule behaves on the way down: the label tells people to take it with a full glass of water, six to eight ounces, and to stay upright for at least 30 minutes, because of oesophageal irritation. (Source 9)

What happens if you do not have it?

Not having clindamycin is the normal state. The question that matters is what happens if a serious bacterial infection goes untreated, and the label answers it indirectly by restricting the drug to serious infections and telling prescribers to weigh the nature of the infection against the suitability of less toxic alternatives such as erythromycin. For most upper respiratory infections, not having it changes nothing, because those are usually not bacterial. (Source 3)

How can you test for it?

Clindamycin blood levels are not routinely measured. The test that is actually used is a susceptibility test on the bacteria causing the infection, which tells the prescriber whether clindamycin will work; the label says bacteriologic studies should be performed to determine the causative organisms and their susceptibility, and points to FDA-recognised interpretive criteria for those methods. If diarrhoea develops, a stool test for C. difficile toxin is the relevant test. (Source 3)

References

1. DailyMed (U.S. National Library of Medicine), Structured Product Label. CLEOCIN HCl (clindamycin hydrochloride) capsules - U.S. prescribing information - Microbiology, Mechanism of Action. 2026. Read the source
2. DailyMed (U.S. National Library of Medicine), Structured Product Label. CLEOCIN HCl (clindamycin hydrochloride) capsules - U.S. prescribing information - BOXED WARNING section. 2026. Read the source
3. DailyMed (U.S. National Library of Medicine), Structured Product Label. CLEOCIN HCl (clindamycin hydrochloride) capsules - U.S. prescribing information - INDICATIONS AND USAGE section. 2026. Read the source
4. The New England journal of medicine. A Placebo-Controlled Trial of Antibiotics for Smaller Skin Abscesses.. 2017. PMID 28657870, DOI 10.1056/nejmoa1607033. Read the source
5. American journal of clinical dermatology. Efficacy and Safety of a Fixed-Dose Clindamycin Phosphate 1.2%, Benzoyl Peroxide 3.1%, and Adapalene 0.15% Gel for Moderate-to-Severe Acne: A Randomized Phase II Study of the First Triple-Combination Drug.. 2022. PMID 34674160, DOI 10.1007/s40257-021-00650-3. Read the source
6. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. Should Linezolid Replace Clindamycin as the Adjunctive Antimicrobial of Choice in Group A Streptococcal Necrotizing Soft Tissue Infection and Toxic Shock Syndrome? A Focused Debate.. 2023. PMID 36056891, DOI 10.1093/cid/ciac720. Read the source
7. The Journal of antimicrobial chemotherapy. Incidence and nature of adverse reactions to antibiotics used as endocarditis prophylaxis.. 2015. PMID 25925595, DOI 10.1093/jac/dkv115. Read the source
8. DailyMed (U.S. National Library of Medicine), Structured Product Label. CLEOCIN HCl (clindamycin hydrochloride) capsules - U.S. prescribing information - Drug Interactions section. 2026. Read the source
9. DailyMed (U.S. National Library of Medicine), Structured Product Label. CLEOCIN HCl (clindamycin hydrochloride) capsules - U.S. prescribing information - DOSAGE AND ADMINISTRATION (adult and pediatric oral dosage). 2026. Read the source
10. The Cochrane database of systematic reviews. Probiotics for the prevention of pediatric antibiotic-associated diarrhea.. 2015. PMID 26695080, DOI 10.1002/14651858.cd004827.pub4. Read the source
11. DailyMed (U.S. National Library of Medicine), Structured Product Label. CLEOCIN HCl (clindamycin hydrochloride) capsules - U.S. prescribing information - PRECAUTIONS, General section. 2026. Read the source
12. DailyMed (U.S. National Library of Medicine), Structured Product Label. CLEOCIN HCl (clindamycin hydrochloride) capsules - U.S. prescribing information - Information for Patients section. 2026. Read the source
13. Antimicrobial agents and chemotherapy. Meta-analysis of antibiotics and the risk of community-associated Clostridium difficile infection.. 2013. PMID 23478961, DOI 10.1128/aac.02176-12. Read the source
14. The Journal of antimicrobial chemotherapy. Antibiotics and hospital-acquired Clostridium difficile infection: update of systematic review and meta-analysis.. 2014. PMID 24324224, DOI 10.1093/jac/dkt477. Read the source
15. Journal of dental research. Risk of Adverse Reactions to Oral Antibiotics Prescribed by Dentists.. 2019. PMID 31314998, DOI 10.1177/0022034519863645. Read the source
16. DailyMed (U.S. National Library of Medicine), Structured Product Label. CLEOCIN HCl (clindamycin hydrochloride) capsules - U.S. prescribing information - ADVERSE REACTIONS (Gastrointestinal, Hypersensitivity Reactions). 2026. Read the source
17. The Cochrane database of systematic reviews. Probiotics for the prevention of pediatric antibiotic-associated diarrhea.. 2015. PMID 26695080, DOI 10.1002/14651858.cd004827.pub4. Read the source
18. The New England journal of medicine. Clindamycin versus trimethoprim-sulfamethoxazole for uncomplicated skin infections.. 2015. PMID 25785967, DOI 10.1056/nejmoa1403789. Read the source
19. DailyMed (U.S. National Library of Medicine), Structured Product Label. CLEOCIN HCl (clindamycin hydrochloride) capsules - U.S. prescribing information - Microbiology, Resistance. 2026. Read the source
20. The New England journal of medicine. A Placebo-Controlled Trial of Antibiotics for Smaller Skin Abscesses.. 2017. PMID 28657870, DOI 10.1056/nejmoa1607033. Read the source
21. The New England journal of medicine. Clindamycin versus trimethoprim-sulfamethoxazole for uncomplicated skin infections.. 2015. PMID 25785967, DOI 10.1056/nejmoa1403789. Read the source
22. American journal of clinical dermatology. Efficacy and Safety of a Fixed-Dose Clindamycin Phosphate 1.2%, Benzoyl Peroxide 3.1%, and Adapalene 0.15% Gel for Moderate-to-Severe Acne: A Randomized Phase II Study of the First Triple-Combination Drug.. 2022. PMID 34674160, DOI 10.1007/s40257-021-00650-3. Read the source