Lithium and salicylate toxicity. Caution with NSAIDs. Antagonized by organic anion drugs (eg, probenecid) and indomethacin. Give oral dose 1hr before or 4-6hrs after cholestyramine. Ototoxicity with aminoglycosides (avoid) and ethacrynic acid. Potentiated by concomitant CYP2C9 inhibitors (eg, amiodarone, fluconazole, miconazole, oxandrolone); monitor and adjust dose if needed. Antagonized by concomitant CYP2C9 inducers (eg, rifampin); monitor and adjust dose if needed. Concomitant CYP2C9 substrates and substrates with narrow therapeutic range (eg, celecoxib, warfarin, phenytoin); monitor and adjust dose if needed. Risk of hypotension and renal impairment with concomitant ACE inhibitors, ARBs, or nephrotoxic drugs (eg, aminoglycosides, cisplatin, NSAIDs). Increased nephrotoxicity with concomitant radiocontrast agents. Increased risk of hypokalemia with concomitant corticosteroids and ACTH.
The most commonly used AAS in medicine are testosterone and its various esters (but most commonly testosterone undecanoate , testosterone enanthate , testosterone cypionate , and testosterone propionate ),  nandrolone esters (most commonly nandrolone decanoate and nandrolone phenylpropionate ), stanozolol , and metandienone (methandrostenolone).  Others also available and used commonly but to a lesser extent include methyltestosterone , oxandrolone , mesterolone , and oxymetholone , as well as drostanolone propionate , metenolone (methylandrostenolone), and fluoxymesterone .  Dihydrotestosterone (DHT; androstanolone, stanolone) and its esters are also notable, although they are not widely used in medicine.  Boldenone undecylenate and trenbolone acetate are used in veterinary medicine .