Procainamide agranulocytosis with

Biood dyscrasias Agranulocytosis, bone marrow depression, neutropenia, hypoplastic anemia and thrombocytopenia in patients receiving procainamide have been reported at a rate of approximately 0.5%. Fatalities have occurred (with approximately 20% to 25% mortality in reported cases of agranulocytosis). Perform complete blood counts including white cell, differential, and platelet counts at weekly intervals for the first 3 months of therapy, and periodically thereafter. Perform complete blood counts promptly if the patient develops any signs of infection (eg. 

Contraindications to procainamide are similar to those for quinidine. Because of its effects on A-V nodal and His-Purkinje conduction, procainamide should be administered with caution to patients with second-degree A-V block and bundle branch block. Procainamide should not be administered to patients who have shown procaine or procainamide hypersensitivity and should be used with caution in patients with bronchial asthma. Prolonged administration should be accompanied by hematological studies, since agranulocytosis may occur. 

Antiarrhythmic therapy carries with it a number of risks. In some cases, the risk of an adverse reaction is clearly related to high dosages or plasma concentrations. Examples include lidocaine-induced tremor or quinidine-induced cinchonism. In other cases, adverse reactions are unrelated to high plasma concentrations (eg, procainamide-induced agranulocytosis). For many serious adverse reactions to antiarrhythmic drugs, the combination of drug therapy and the underlying heart disease appears important. 

Procainamide and quinidine cdrnmonly cauie Gl upset (nausea, vomiting, diarrhea) and hj otension. Less commonly, procainamide is associated with agranulocytosis end iupus-Uke syndrome Additional side effects of quinidine include thrombocytopenia and cinchonism. ... 

Procainamide may induce a syndrome similar to systemic lupus erythematosus. This syndrome consists of arthralgias, myalgias, pleurisy, rash, fever, and elevated nuclear antibodies. Patients who are slow acetylators are at increased risk for developing this syndrome. While some studies have reported that less than one in 500 on chronic procainamide therapy developed this syndrome, others have reported this syndrome in up to 30% of patients on long-term therapy. Other side effects with chronic use include development of neutropenia, thrombocytopenia, hemolytic anemia, agranulocytosis, liver failure, a myasthenia-like syndrome, and psychosis with hallucinations. 

There may be ethnic differences in susceptibility to ADRs. Corzo et al (1995) identified an association of alleles of the HLA-B and DR loci with increased risk of clozapine-induced agranulocytosis. Patients with abnormal pscudocholinesterase levels have prolonged apnea after receiving succi-nylcholine. Patients with low activity on N-acetyl transferase are more likely to develop lupus-like reactions to procainamide, hydralazine and isonia-zid (Peck et al 1993). 

Rashes of various types have been reported associated with procainamide, but two cases worthy of special mention are a case of generalized vasculitis reported by Dolan (1968) and a case of digital vasculitis reported by Rosin (1967) both could indicate some immune complex phenomena. Agranulocytosis developing after 26-78 days of treatment with the drug and not clearly dose-related has been reported in 12 cases (Wang and Schuller 1969 Konttinen and Tuominen 1971 Hickson et al. 1972 Hensen 1974). 

Fever with nausea and vomiting developed in a patient who had taken procainamide for V-k weeks the symptoms persisted for several days, but resolved within 24 hr on withdrawal of the drug (45 ). A further case of agranulocytosis which was thought to be caused by procainamide has been reported however, the patient had received no less than 20 other drugs, at least one of which has been known to cause agranulocytosis, so the case cannot be recorded as proven (46 ). 

Hypotension. Diarrhea. Dizziness. Liver failure. Lupus erythematosus-like syndrome. Nausea and vomiting. Heart block. Agranulocytosis. Procainamide increases risk of death in patients with non-life-threatening arrhythmias. Use with caution in patients with liver or kidney dysfunction. Tell patient not to crush or break extended-release tablets. 

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