Agranulocytosis

• β-lactam antimicrobials, chloramphenicol, chloroquine, clindamycin, dapsone, doxycycline, flucytosine, ganciclovir, isoniazid, metronidazole, nitrofurantoin, pyramethamine, rifampin, streptomycin, sulfonamide antimicrobials, vancomycin, and zidovudine

• Acetazolamide, captopril, ethacrynic acid, furosemide, hydralazine, methazolamide, methyldopa, procainamide, thiazide diuretics, and ticlopidine

• Allopurinol, aspirin, carbamazepine, chlorpropamide, clomipramine, clozapine, colchicine, desipramine, gold salts, imipramine, levodopa, penicillamine, phenothiazines, phenytoin, propylthiouracil, and sulfonylureas

Aplastic anemia

• Acetazolamide, allopurinol, aspirin, captopril, carbamazepine, chloramphenicol, chlorpromazine, dapsone, felbamate, gold salts, metronidazole, methimazole, penicillamine, pentoxifylline, phenothiazines, phenytoin, propylthiouracil, quinidine, sulfonamide antimicrobials, sulfonylureas, and ticlopidine

Hemolysis (oxidative)

• Benzocaine, β-lactams, chloramphenicol, chloroquine, dapsone, hydroxychloroquine, methylene blue, nitrofurantoin, phenazopyridine, rasburicase, and sulfonamide antimicrobials

Hemolytic anemia

• β-lactam antimicrobials, gatifloxacin, indinavir, isoniazid, levofloxacin, nitrofurantoin, ribavirin, rifabutin, rifampin, silver sulfadiazine, streptomycin, sulfonamide antimicrobials, and tetracyclines

• Acetazolamide, amprenavir, captopril, hydralazine, hydrochlorothiazide, methyldopa, procainamide, quinidine, ticlopidine, and triamterene

• Levodopa, methylene blue, phenazopyridine, quinine, and tacrolimus

Megaloblastic anemia

• Azathioprine, chloramphenicol, colchicine, cyclophosphamide, cytarabine, 5-fluorodeoxyuridine, 5-fluorouracil, hydroxyurea, mercaptopurine, metformin, methotrexate, phenobarbital, phenytoin, primidone, proton pump inhibitors, pyrimethamine, sulfasalazine, and vinblastine

Methemoglobinemia

• Benzocaine, cetacaine, EMLA cream, lidocaine, prilocaine, and procaine

• Chloroquine, dapsone, methylene blue (doses ≥4 mg/kg), nitrofurantoin, phenazopyridine, primaquine, rasburicase, and sulfonamide antimicrobials

• Nitrates (e.g., amyl nitrate and nitroglycerin) and nitroprusside

Thrombocytopenia

• Amphotericin B products, β-lactam antimicrobials, isoniazid, linezolid, rifampin, sulfonamide antimicrobials, and vancomycin

• Abciximab, aminophylline, amiodarone, amrinone, aspirin, carbamazepine, chlorpromazine, danazol, diltiazem, eptifibatide, heparin, histamine₂-receptor antagonists, low molecular weight heparins, methyldopa, milrinone, procainamide, quinidine, quinine, NSAIDs, thiazide diuretics, ticlopidine, tirofiban, and valproic acid

• Discontinue all heparin and low molecular weight heparin sources

   ○ Intravenous, subcutaneous, flushes, and heparin-coated catheters

• Monitor for evidence of thrombosis

• Avoid low molecular weight heparins (high cross-reactivity)

• Avoid warfarin monotherapy during the acute phase of heparin-induced thrombocytopenia (HIT)

   ○ Has been associated with paradoxical venous limb gangrene and skin necrosis. If warfarin has been initiated at the time HIT is recognized, reverse with vitamin K₁ (5–10 mg enterally or intravenously × 1 or 2 doses)