Drug Interactions between aspirin/citric acid/sodium bicarbonate and carboplatin

MONITOR: Coadministration of carboplatin with other nephrotoxic agents may increase the risk of renal impairment due to additive effects on the kidney. Moreover, renal impairment secondary to the use of these agents may reduce the clearance of carboplatin, which is primarily eliminated by renal excretion. This may increase the risk of other adverse effects including severe myelosuppression which is concentration-dependent. Approximately 25% of patients receiving carboplatin exhibit decreases in creatinine clearance, whereas rises in serum creatinine and blood urea nitrogen occur less frequently. Some data suggests hypomagnesemia is the primary indicator of carboplatin-induced nephrotoxicity. Patients receiving multiple courses or single doses exceeding 800 mg/m2 of carboplatin, or those with a history of cisplatin-induced nephrotoxicity, may be at increased risk of renal toxicity.

MANAGEMENT: Renal function and serum magnesium levels should be monitored if carboplatin is used concomitantly with other nephrotoxic agents. The potential for increased toxicity of carboplatin such as peripheral sensory neuropathies and myelosuppression should be considered.

MONITOR: Agents that cause urinary alkalinization can reduce serum salicylate concentrations in patients receiving anti-inflammatory dosages of aspirin or other salicylates. The mechanism involves reduction in salicylate renal tubular reabsorption due to increased urinary pH, resulting in increased renal salicylate clearance especially above urine pH of 7. This interaction is sometimes exploited in the treatment of salicylate toxicity.

MANAGEMENT: Patients treated chronically with urinary alkalinizers and large doses of salicylates (i.e. 3 g/day or more) should be monitored for potentially diminished or inadequate analgesic and anti-inflammatory effects, and the salicylate dosage adjusted if necessary.