LactMed lists potentially negative gastrointestinal effects in babies whose mothers take it while breastfeeding but did not see that as justification to stop breastfeeding. Interactions
Clindamycin may prolong the effects of neuromuscular-blocking drugs, such as succinylcholine and vecuronium. Its similarity to the mechanism of action of macrolides and chloramphenicol means they should not be given simultaneously, as this causes antagonism and possible cross-resistance. Chemistry
Clindamycin is a semisynthetic derivative of lincomycin, a natural antibiotic produced by the actinobacterium Streptomyces lincolnensis. It is obtained by 7(S)-chloro-substitution of the 7(R)-hydroxyl group of lincomycin. The synthesis of clindamycin was first announced by BJ Magerlein, RD Birkenmeyer, and F Kagan on the fifth Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in 1966. It has been on the market since 1968.Clindamycin is white or yellow. It is very soluble in water. The topically used clindamycin phosphate is a phosphate-ester prodrug of clindamycin. Mechanism of action
Clindamycin has a primarily bacteriostatic effect. At higher concentrations, it may be bactericidal. It is a bacterial protein synthesis inhibitor by inhibiting ribosomal translocation, in a similar way to macrolides. It does so by binding to the rRNA of the bacterial 50S ribosome subunit, overlapping with the binding sites of the oxazolidinone, pleuromutilin, and macrolide antibiotics, among others. The binding is reversible.
Side effects
Common adverse drug reactions associated with systemic clindamycin therapy – found in over 1% of people – include: diarrhea, pseudomembranous colitis, nausea, vomiting, abdominal pain or cramps and/or rash. High doses (both intravenous and oral) may cause a metallic taste. Common adverse drug reactions associated with topical formulations – found in over 10% of people – include: dryness, burning, itching, scaliness, or peeling of skin (lotion, solution); erythema (foam, lotion, solution); oiliness (gel, lotion). Additional side effects include contact dermatitis. Common side effects – found in over 10% of people – in vaginal applications include fungal infection.Rarely –  in less than 0.1% of people –  clindamycin therapy has been associated with anaphylaxis, blood dyscrasias, polyarthritis, jaundice, raised liver enzyme levels, renal dysfunction, cardiac arrest, and/or hepatotoxicity. Clostridioides difficile
Pseudomembranous colitis is a potentially lethal condition commonly associated with clindamycin, but which also occurs with other antibiotics. Overgrowth of Clostridioides difficile, which is inherently resistant to clindamycin, results in the production of a toxin that causes a range of adverse effects, from diarrhea to colitis and toxic megacolon. Pregnancy and breastfeeding
Use of clindamycin during pregnancy is generally considered safe.Clindamycin is classified as compatible with breastfeeding by the American Academy of Pediatrics, however, the WHO categorizes it as "avoid if possible". It is classified as L2 probably compatible with breastfeeding according to Medications and Mothers Milk. A 2009 review found it was likely safe in breastfeeding mothers, but did find one complication (hematochezia) in a breastfed infant which might be attributable to clindamycin.