- Patients on amphotericin, pyrimethamine, sulfadiazine, trimethoprim/sulfamethoxazole, ganciclovir, intravenous pentamidine, intravenous acyclovir = or > 1000 mg/day orally or other bone marrow or renal toxic drugs may not tolerate concomitant ddC. If these drugs are given concomitantly with ddC, patients should have frequent (weekly) laboratory assessments, as appropriate.