<p>High doses of NSAIDs and aspirin may reduce the elimination of pemetrexed; avoid usage 2 days (5 days for longer-acting NSAIDs) before, during and 2 days after treatment with pemetrexed in patients with impaired renal function. Additive GI side effects when used with SSRIs, acetylcholinesterase inhibitors, aripiprazole or ziprasidone. Additive sedation when used with psychotropics. Concurrent use with nephrotoxic drugs (e.g. aminoglycosides, loop diuretics, platinum compounds and ciclosporin) may decrease pemetrexed clearance, thus increasing the risk of toxicity. Clearance may be reduced when used with drugs that are cleared by tubular secretion e.g. probenecid and penicillin.</p>