Clindamycin: May enhance the action of neuromuscular blocking agents (e.g. atracurium). May antagonise the effects of parasympathomimetics. May competitively inhibit the effects of macrolides, ketolides, streptogramins, linezolid and chloramphenicol. Increased coagulation tests (prothrombin time/INR) and/or bleeding w/ vit K antagonists (e.g. warfarin, acenocoumarol, fluindione).
Tretinoin: Enhances percutaneous absorption of minoxidil. Increased risk of fatal thrombotic complications with antifibrinolytic. Increased tretinoin concentrations with azole antifungals. Enhances peeling action of sulphur, resorcinol, benzoyl peroxide, salicylic acid. Increased photosensitivity with photosensitising medications eg, thiazides, tetracyclines, fluoroquinolones, phenothiazines and sulfonamides.
Potentially Fatal: Increased risk of intracranial pressure with tetracyclines.