Clinical safety rating: safe
Human studies have proved safety
Inhibits bacterial protein synthesis by binding to the 50S subunit of the ribosome, blocking peptide bond formation.
| Metabolism | Primarily hepatic via CYP3A4 and CYP3A5; metabolites include N-demethylclindamycin and sulfoxide derivatives. |
| Excretion | Approximately 10% of active drug and 90% as inactive metabolites via renal (feces 3.6% as active, bile significant for enterohepatic circulation). |
| Half-life | 2.4 hours (range 1.5-5.1 hours) in adults with normal renal function; prolonged in severe hepatic impairment. |
| Protein binding | 90-94% bound, primarily to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | 0.6-1.2 L/kg; extensive tissue penetration including bone and abscesses. |
| Bioavailability | Oral: 90% (capsule); topical: 1-5% systemic absorption; IM: 100%. |
| Onset of Action | Oral: 45-60 minutes; IM: 1-2 hours; IV: immediate (within minutes). |
| Duration of Action | 6-8 hours for most indications; sustained release formulations up to 12 hours. |
| Molecular Weight | 424.98 |
150-450 mg orally every 6 hours; 600 mg to 1.2 g intravenously every 6-8 hours; maximum 4.8 g/day IV.
| Renal impairment | No significant adjustment required; dose reduction not necessary in renal impairment. |
| Liver impairment | Child-Pugh A or B: no adjustment; Child-Pugh C: reduce dose by 50% or extend interval to every 8-12 hours. |
| Pediatric use | Oral: 8-20 mg/kg/day divided every 6-8 hours; IV: 20-40 mg/kg/day divided every 6-8 hours. |
| Geriatric use | Monitor renal and hepatic function; no specific dose adjustment recommended based on age alone. |
| 1st trimester | Crosses placenta; no well-controlled studies but animal studies show no fetal harm at therapeutic doses. Generally considered safe if clinically indicated. |
| 2nd trimester | Crosses placenta; no evidence of teratogenicity in humans. Use if benefit outweighs risk. |
| 3rd trimester | Crosses placenta; may alter neonatal gut flora. Avoid near term unless essential, due to potential for pseudomembranous colitis in neonate. |
Clinical note
Safe and effective for anaerobic bacterial infections, group A streptococcal infections, and bacterial vaginosis (BV) in pregnancy. First-line topical/vaginal gel for BV in all trimesters as an alternative to metronidazole. No evidence of teratogenicity in human studies.
| Placental transfer | Crosses placenta; cord blood levels are about 50% of maternal serum levels. |
| Breastfeeding | Enters breast milk in low amounts (less than 1 mg/L); unlikely to cause adverse effects in infant. However, theoretical risk of altering infant gut flora or causing diarrhea. Monitor infant for gastrointestinal symptoms. |
■ FDA Black Box Warning
Clindamycin can cause Clostridioides difficile-associated diarrhea (CDAD), which may range from mild diarrhea to fatal colitis. If CDAD is suspected or confirmed, antibiotic use may need to be discontinued.
| Serious Effects |
Hypersensitivity to clindamycin or lincomycinHistory of pseudomembranous colitisHepatic impairment (severe) — relative
| Precautions | Risk of Clostridioides difficile colitis, May cause hypersensitivity reactions including anaphylaxis, Neuromuscular blocking effects; use with caution in patients with neuromuscular disease, May result in overgrowth of non-susceptible organisms, Use with caution in patients with gastrointestinal disease, particularly colitis, Hepatic impairment may require dose adjustment |
| Food/Dietary | Clindamycin can be taken with or without food; however, taking with a full glass of water may reduce esophageal irritation. Avoid alcohol due to potential increased gastrointestinal side effects (though not a true disulfiram reaction). No significant food interactions. |
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| Lactation Rating | L2 (Probably Compatible) |
| Teratogenic Risk | Clindamycin is classified as FDA Pregnancy Category B. Animal reproduction studies have not demonstrated a risk to the fetus, but there are no adequate and well-controlled studies in pregnant women. It is considered low risk; however, it should be used only if clearly needed. No known teratogenic effects have been reported in humans, but data are limited. Trimester-specific risks: first trimester - no evidence of increased malformations; second and third trimesters - considered safe for treatment of infections. |
| Fetal Monitoring | Standard monitoring for infection resolution. No specific fetal monitoring required. Monitor for maternal adverse effects such as gastrointestinal disturbances, including Clostridioides difficile infection. In newborns exposed via breast milk, monitor for diarrhea or thrush. |
| Fertility Effects | No known significant effects on human fertility. Animal studies have not reported adverse effects on fertility or reproductive performance. |
| Clinical Pearls | Clindamycin is a lincosamide antibiotic with excellent bone and soft tissue penetration, making it a drug of choice for diabetic foot infections and osteomyelitis. It is often used in combination with beta-lactams for anaerobic coverage due to its activity against B. fragilis. Caution: high risk of C. difficile colitis; avoid in patients with inflammatory bowel disease. It can be used for GABHS tonsillitis in penicillin-allergic patients but resistance rates may be high in some regions. Intravenous administration can cause thrombophlebitis; dilute appropriately and rotate sites. |
| Patient Advice | Take exactly as prescribed; do not skip doses even if you feel better. · May cause diarrhea; contact your doctor if you have watery or bloody stools, or abdominal cramping. · Avoid alcohol while taking this medication. · Inform your doctor of any history of colitis or gastrointestinal disease. · If you are using birth control pills, use an additional barrier method as clindamycin may reduce efficacy. · Do not take with antacids or kaolin-pectin; separate by at least 2 hours. |