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Abstract
Thirty-three patients with ventricular tachyarrhythmias were referred for evaluation of their arrhythmias using programmed electrical stimulation to guide antiarrhythmic therapy. Cibenzoline succinate, a new antiarrhythmic agent, was compared to procainamide in patients with ventricular tachycardia. Cibenzoline was given intravenously, initially 1.0 mg/kg, then in 1 mg/kg increments to a maximum of 3.0 mg/kg, during electrophysiologic testing. The results were compared to procainamide, which was also administered intravenously to 1000 and then to 1500 mg. Cibenzoline provided protection against ventricular tachycardia induction in 16 of 33 patients. The PR interval increased 13%, QRS duration widened 26%, and QTc interval was prolonged by 7%. There was a 9% fall in mean arterial blood pressure. Procainamide prevented ventricular tachycardia induction in 21 out of 31 patients tested. The PR interval increased 11%, QRS duration widened 27%, and QTc interval prolonged by 8%. Cibenzoline was given orally to 13 patients for chronic treatment. Chronic oral cibenzoline therapy after a mean follow-up of 8.8 months caused a reduction of ventricular ectopy from 666 to 190 beats/hr. Ventricular tachycardia events decreased per Holter monitor recording from 6 to 0.6. Cibenzoline therapy was discontinued in 5 of 13 patients due to break-through arrhythmias (nonsustained ventricular tachycardia on Holter monitor and recurrence of symptoms). Cibenzoline may be an effective antiarrhythmic agent in selected patients.
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102
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DiPersio DM, Chow MS. Predicting plasma procainamide concentrations resulting from a sustained-release preparation. CLINICAL PHARMACY 1985; 4:186-91. [PMID: 3987218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Two methods of predicting plasma procainamide concentrations (PPCs) for a sustained-release procainamide (SRP) dosage form were compared using previously published data on 12 healthy subjects. Methods A and B were both based on a one-compartment pharmacokinetic model requiring an elimination rate constant and area under the concentration-time curve from an immediate-release oral procainamide dosage form and in vitro dissolution data from the SRP product. Method A also used an absorption rate constant. The predicted versus measured PPCs for two sets of peak and trough concentrations in each subject were evaluated using linear regression. The mean predicted PPCs by both methods followed the measured PPCs closely; however, the time of peak concentration was predicted more accurately by method A. The evaluation of predictive performance showed good precision and a small but statistically significant bias with either method, peak values were overpredicted and trough values were underpredicted. These two methods adequately predicted plasma procainamide concentrations in healthy subjects following a sustained-release procainamide preparation.
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103
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Somberg J, Butler B, Flowers D, Keefe D, Torres V, Miura D. Long-term lorcainide therapy in patients with ventricular tachycardia. Am Heart J 1985; 109:33-40. [PMID: 3966330 DOI: 10.1016/0002-8703(85)90412-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
One hundred patients inducible at electrophysiologic studies underwent serial drug testing with procainamide, lidocaine, and lorcainide to determine comparative efficacy. Acute intravenous administration was followed by repeat programmed electrical stimulation (PES) studies on separate days for each antiarrhythmic drug. Lorcainide prevented ventricular tachycardia (VT) induction in 69% of the 100 patients studied, procainamide was effective in 50% of the 75 patients studied, and lidocaine prevented VT induction in 30% of 53 patients. Following PES and serial drug testing, 46 patients were started on lorcainide, nine patients on procainamide, and 45 patients were started on other antiarrhythmic drug regimens. Seventy percent of the patients have remained on lorcainide therapy, while 47% have continued on other drug therapies started over a 20.5 +/- 3.2-month mean follow-up period. Despite sleep-wake disturbances and a need for sedation at night, lorcainide therapy was tolerated well in this population and remained an effective antiarrhythmic with prolonged administration.
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104
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Somberg J, Torres V, Flowers D, Miura D, Butler B, Gottlieb S. Prolongation of QT interval and antiarrhythmic action of bepridil. Am Heart J 1985; 109:19-27. [PMID: 3871296 DOI: 10.1016/0002-8703(85)90410-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Studies were undertaken with bepridil, a new calcium blocker that prolongs the QT interval, to determine the antiarrhythmic and possible arrhythmogenic properties of this agent. The technique of programmed electrical stimulation was employed to evaluate bepridil in 15 patients with symptomatic ventricular tachycardia (VT). Bepridil prevented VT induction in 7 of 15 patients. Bepridil prolonged the QT and refractoriness and a linear correlation could be demonstrated between the percent change in QTc and refractory period prolongation for the bepridil-protected group. Bepridil in one patient reduced by one the number of stimuli required to induce VT, but no spontaneous arrhythmias were noted. Bepridil thus possesses antiarrhythmic properties with a minimal proarrhythmic effect.
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105
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Marchlinski FE, Buxton AE, Vassallo JA, Waxman HL, Cassidy DM, Doherty JU, Josephson ME. Comparative electrophysiologic effects of intravenous and oral procainamide in patients with sustained ventricular arrhythmias. J Am Coll Cardiol 1984; 4:1247-54. [PMID: 6209319 DOI: 10.1016/s0735-1097(84)80145-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Thirty-three patients with sustained ventricular arrhythmias underwent electrophysiologic testing after intravenous and again after oral procainamide administration. Two groups were identified: group 1 included 15 patients with concordant serum procainamide concentrations with less than a 3 micrograms/ml difference after intravenous (mean 8.6 +/- 2.7) and oral (mean 8.8 +/- 2.7) procainamide administration, with mean N-acetylprocainamide concentrations of 1.0 +/- 0.6 and 6.2 +/- 2.8 micrograms/ml, respectively. Group 2 included 18 patients with discordant serum procainamide concentrations after intravenous (mean 9.5 +/- 5.9 micrograms/ml) and oral (mean 14.1 +/- 5.2 micrograms/ml) procainamide, with mean N-acetylprocainamide concentrations of 0.9 +/- 0.5 and 10.7 +/- 5.7 micrograms/ml, respectively. In group 1, response to programmed stimulation was the same after intravenous and oral procainamide administration, with no inducible ventricular arrhythmia in 5 of 15 patients. In group 2, 3 of 18 patients had no inducible arrhythmia after intravenous compared with 7 of 18 patients after oral procainamide administration. There was a different response to programmed stimulation after oral compared with intravenous procainamide in 6 of 18 patients in group 2 but in none of 15 patients in group 1 (p = 0.02). The effective procainamide concentration was greater than the ineffective concentration in five of the six patients with a discordant response, and the effective route of administration was oral in five of the six patients. The change in ventricular refractoriness in group 1 was similar after intravenous (28 +/- 23 ms) and oral (29 +/- 19 ms) procainamide, whereas in group 2, refractoriness was increased more after oral (33 +/- 21 ms) than intravenous (20 +/- 17 ms) procainamide administration and paralleled the difference in procainamide concentration.(ABSTRACT TRUNCATED AT 250 WORDS)
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106
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Grauer K, Lopez LM, Curry RW, Kravitz L, Robinson JD, Sands CR. Ventricular ectopy. THE JOURNAL OF FAMILY PRACTICE 1984; 19:731-3, 737, 741-2 passim. [PMID: 6209358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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107
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Schwartz AB, Klausner SC, Yee S, Turchyn M. Cerebellar ataxia due to procainamide toxicity. ARCHIVES OF INTERNAL MEDICINE 1984; 144:2260-1. [PMID: 6497531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
It has become appreciated that drug levels of procainamide hydrochloride needed to suppress inducible ventricular tachycardia by programmed ventricular stimulation exceed the previously published therapeutic range. Cerebellar ataxia developed acutely in a patient receiving high-dose procainamide. This was associated with a marked increase in the serum drug level. Resolution occurred within three days after drug therapy was discontinued.
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108
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Kessler KM, Kissane B, Cassidy J, Pefkaros KC, Kozlovskis P, Hamburg C, Myerburg RJ. Dynamic variability of binding of antiarrhythmic drugs during the evolution of acute myocardial infarction. Circulation 1984; 70:472-8. [PMID: 6744551 DOI: 10.1161/01.cir.70.3.472] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We tested the hypothesis that the changes in free fatty acid and alpha 1-glycoprotein concentrations, which occur during acute myocardial infarction, exert asynchronous and opposing influences on the serum protein binding of selected drugs. Free drug fractions of two antiarrhythmic agents with contrasting binding characteristics, quinidine and procainamide, were related to free fatty acid and alpha 1-glycoprotein concentrations on days 1 through 5 and 10 in 20 patients with acute myocardial infarction. The mean free quinidine fraction was elevated on day 1 (9.0 +/- 4.4% vs 6.7 +/- 2.7% in patients with stable heart disease; p less than .05) and fell progressively to day 10 (4.0 +/- 2.8%; p less than .0002) as free fatty acid concentration decreased (day 1 = 464 +/- 272 meq/liter; day 10 = 264 +/- 155 meq/liter; p less than .01) and alpha 1-glycoprotein concentration increased (day 1 = 98 +/- 31 mg/dl; day 10 = 141 +/- 47 mg/dl; p less than .02). Multiple stepwise regression showed a major influence of changing alpha 1-glycoprotein concentration on the observed sequential changes in the free quinidine fraction (p less than .005). In contrast, no serial changes in procainamide binding were noted. In conclusion, metabolic changes during the course of acute myocardial infarction sequentially alter free quinidine fraction and, consequently, may influence pharmacodynamics.
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109
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Somogyi A, Bochner F. Dose and concentration dependent effect of ranitidine on procainamide disposition and renal clearance in man. Br J Clin Pharmacol 1984; 18:175-81. [PMID: 6091709 PMCID: PMC1463520 DOI: 10.1111/j.1365-2125.1984.tb02450.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The pharmacokinetics of oral procainamide (1 g) were investigated in six healthy subjects during chronic dosing with ranitidine 150 mg twice daily, and in three of the subjects when ranitidine 750 mg was administered over 12 h. The procainamide area under the plasma concentration-time curve was significantly (PQ0.02) increased by ranitidine (27.761.5 vs 31.561.8 mg l-1 h) with a significant reduction in renal clearance (379632 vs 309630 ml/min, PQ0.02). There was no change in half-life. The N-acetylprocainamide (NAPA) area under the plasma concentration-time curve was also significantly (PQ0.02) elevated by ranitidine (8.661.2 vs 9.761.3 mg 1-1 h) due to a reduction in renal clearance from 187630 to 168628 ml/min. The larger dose of ranitidine produced greater alterations in the procainamide and NAPA pharmacokinetics. Ranitidine reduced the absorption of procainamide by 10% and by 24% at the higher dose level. Two-hourly renal clearance values of procainamide were significantly (PQ0.05) reduced in the 2 to 10 h period and for NAPA between 0 to 6 and 8 to 10 h. The larger ranitidine dose reduced the renal clearances of procainamide and NAPA over the control period at each 2-hourly time period. The reductions in renal clearance are most likely mediated by competition for the renal tubular cationic secretory pathway. Clinical implications arising from this study suggest a reduction in procainamide dosage may be necessary in a small, select number of patients with high plasma ranitidine concentrations, e.g., the elderly; furthermore, failure of therapeutic response for some drugs may be due to ranitidine-induced impaired gastrointestinal absorption.
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110
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Kroboth PD, Mitchum K, Puschett JB. Use of procainamide in chronic ambulatory peritoneal dialysis: report of a case. Am J Kidney Dis 1984; 4:78-9. [PMID: 6204527 DOI: 10.1016/s0272-6386(84)80032-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A patient on chronic ambulatory peritoneal dialysis (CAPD) was treated with procainamide for control of ventricular arrhythmias. A procainamide half-life of 11.5 hours was observed, with a dialysis clearance of 6.5 mL/min. The N-acetylprocainamide (NAPA) dialysis clearance was 5.3 mL/min. The CAPD clearance of procainamide and its active metabolite, NAPA, is much lower than that reported for hemodialysis. Procainamide therapy should be initiated with reduced dosages in patients with renal failure.
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111
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Ching MS, Mihaly GW, Jones DB, Smallwood RA. Liquid chromatographic analysis of cimetidine with procainamide as internal standard. J Pharm Sci 1984; 73:1015. [PMID: 6470945 DOI: 10.1002/jps.2600730745] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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112
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Hull RL. Bioequivalency of sustained-release procainamide. DRUG INTELLIGENCE & CLINICAL PHARMACY 1984; 18:531. [PMID: 6734442 DOI: 10.1177/106002808401800616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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113
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Wisenberg G, Zawadowski AG, Gebhardt VA, Prato FS, Goddard MD, Nichol PM, Rechnitzer PA, Gryfe-Becker B. Effects on ventricular function of disopyramide, procainamide and quinidine as determined by radionuclide angiography. Am J Cardiol 1984; 53:1292-7. [PMID: 6711431 DOI: 10.1016/0002-9149(84)90082-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
To evaluate the effects of the 3 commonly used antiarrhythmic agents--disopyramide, procainamide and quinidine--on left ventricular (LV) function, these 3 agents were administered in random sequence after control radionuclide angiography performed at rest and during exercise in 17 patients. Drug dosages were tailored to achieve therapeutic blood levels 5 minutes before and 2 to 3 hours after drug administration. The mean dose of disopyramide was 141 +/- 26 mg every 6 hours, procainamide, 441 +/- 100 mg every 4 hours, and quinidine, 401 +/- 101 mg of the gluconate preparation every 6 hours. The patients received the appropriate dosage for 7 or more days before repeat radionuclide angiography was performed. The ejection fraction at rest was: control 60 +/- 13%, disopyramide 55 +/- 11%, procainamide 58 +/- 11%, and quinidine 59 +/- 12%. The exercise ejection fraction was: control 61 +/- 14%, disopyramide 58 +/- 13%, procainamide 58 +/- 12% and quinidine 61 +/- 13%. In neither case, at rest nor during exercise was there any significant difference observed between any of the agents or between any individual agent and control. However, at rest 8 subjects had a 5% or more decrease from the control value with disopyramide, 5 had a 5% or more decrease with procainamide and 6 had a 5% or more decrease with quinidine, whereas during exercise the decreases were 8, 6 and 5%, respectively. These values were not statistically different but suggest that caution should be taken in administering all 3 agents, particularly to patients with impaired LV function, because individual sensitivity to a given agent may precipitate a significant decline in LV function.
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114
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Saal AK, Werner JA, Greene HL, Sears GK, Graham EL. Effect of amiodarone on serum quinidine and procainamide levels. Am J Cardiol 1984; 53:1264-7. [PMID: 6711425 DOI: 10.1016/0002-9149(84)90076-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Serum levels of quinidine or procainamide were measured in patients who had amiodarone added to their antiarrhythmic regimen. Dosages of quinidine or procainamide were held constant. Eleven of 11 patients had an increase in the serum quinidine level, and 11 of 12 other patients had an increase in the serum procainamide level. The dose requirement to maintain a stable plasma level of quinidine or procainamide decreased by 37% and 20%, respectively. Clinical toxicity occasionally occurred with the increase in serum levels of quinidine and procainamide, and the dose of these drugs should be decreased when amiodarone is administered concurrently.
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115
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MacKichan JJ, Coyle JD, Shields BJ, Boudoulas H, Lima JJ. Fluoroimmunoassays for procainamide and N-acetylprocainamide compared with a liquid-chromatographic method. Clin Chem 1984; 30:768-73. [PMID: 6201304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We measured procainamide and its active metabolite, N-acetylprocainamide (NAPA), in 80 sera from 37 patients by a new fluorimmunoassay procedure and an established "high-performance" liquid-chromatographic method. Additive and proportional differences between the methods were 0.07 mg/L and 9%, respectively, for procainamide and 0.62 mg/L and 16% for NAPA. Between-day CVs by the chromatographic and immunoassay methods, respectively, were 3.9% and 2.2% for procainamide at a concentration of 6 mg/L, and 5.1% and 1.2% for NAPA (14 mg/L). We applied a modification of the fluoroimmunoassay for determination of procainamide concentrations, using sera obtained during a pharmacokinetic study, and demonstrated excellent agreement with the chromatographic method.
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116
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Abstract
In this article, many of the reports which describe the various assay procedures for 8 of the most commonly monitored drugs in plasma (digoxin, gentamicin, phenobarbitone, phenytoin, procainamide, quinidine, salicylates and theophylline) are reviewed, together with studies dealing with interferences of other drugs with these assays. Factors which are evaluated include whether the interference was studied when the drug was taken by a patient or a volunteer or by adding it to serum in vitro, the concentration or dose of the interfering drug (when reported), and the clinical implications of the interference. Suggestions as to how to eliminate some of these potential sources of interference are made.
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117
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Kark B, Sistovaris N, Keller A. Thin-layer chromatographic determination of procainamide and N-acetylprocainamide in human serum and urine at single-dose levels. JOURNAL OF CHROMATOGRAPHY 1983; 277:261-72. [PMID: 6196373 DOI: 10.1016/s0378-4347(00)84843-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Thin-layer chromatographic methods were applied for bioavailability studies of procainamide in serum and urine. Detection of the parent compound and the major metabolite was performed in the ultraviolet range at 275 nm. Using 100-microliter samples, detection limits were 60 ng of procainamide-HCl per ml serum and 7 micrograms/ml urine, and 60 ng of N-acetylprocainamide-HCl per ml serum and 5 micrograms/ml urine. Advantages over previous methods are discussed. From serum and urine data of five volunteers, the bioavailability of procainamide from a 250-mg dragee preparation compared with an intravenous dose was verified. Pharmacokinetic data were computed using one-compartment open models. Results corresponded well with values previously published.
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118
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van Pham C, Noguchi J, Quismorio FP, Haywood LJ. Low-dose procainamide: low risk of complications with long-term use. J Natl Med Assoc 1983; 75:705-8. [PMID: 6887275 PMCID: PMC2561492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The incidence of procainamide-induced drug reactions was studied prospectively in 55 patients receiving long-term therapy with a mean duration of 23 months. New symptoms that occurred in 13 patients after the drug was started were similar to complaints presented by 25 patients before the medication was started. Duration of therapy was positively correlated with new symptom occurrence (P < .05) but not with age, sex, dose, or dose interval. Other concomitant drugs did not influence the results. Antideoxyribonucleoprotein antibodies were positive in 27 patients (55 percent) and in seven of 13 with new symptoms; female sex (P < .05) and increasing age (P < .05) favored a positive test. Anti-DNA antibodies were not found in any patients. Procainamide, at a mean dose of 1.5 g/day, was judged to be therapeutically effective by the clinic staff independent of this study; the drug was not discontinued in any patient because of the severity of symptoms.
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119
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Patel CP. Improved liquid chromatographic determination of procainamide and N-acetylprocainamide in serum. Ther Drug Monit 1983; 5:235-8. [PMID: 6192559 DOI: 10.1097/00007691-198306000-00016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A liquid chromatographic method for the determination of procainamide (PA) and N-acetylprocainamide (NAPA) in serum has been developed. This method utilizes isocratic conditions, ambient temperature, and a conventional fixed-wavelength 280-nm detector. Sample pretreatment involves extraction of PA and NAPA, along with p-amino-N-(2-dipropylaminoethyl)-benzamide hydrochloride as internal standard, into an organic phase and reextraction into an aqueous acidic phase. Using this sample pretreatment, interferences due to commonly used drugs are eliminated. The method accurately measures PA and NAPA to levels as low as 1 mg/L.
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120
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Chen ML, Lee MG, Chiou WL. Pharmacokinetics of drugs in blood III: Metabolism of procainamide and storage effect of blood samples. J Pharm Sci 1983; 72:572-4. [PMID: 6191022 DOI: 10.1002/jps.2600720527] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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121
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Vlasses PH, Rocci ML, Porrini KA, Greenspon AJ, Ferguson RK. Immediate-release and sustained-release procainamide: bioavailability at steady state in cardiac patients. Ann Intern Med 1983; 98:613-4. [PMID: 6189438 DOI: 10.7326/0003-4819-98-5-613] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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122
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123
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Zema MJ, Mirando T. Serum drug concentrations in patients with ischemic heart disease after administration of a sustained release procainamide preparation. Angiology 1983; 34:32-9. [PMID: 6186164 DOI: 10.1177/000331978303400104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Despite widespread marketing of a sustained release preparation of procainamide hydrochloride (PROCAN-SR, Parke-Davis), published literature demonstrating its efficacy in maintaining uniform serum drug levels over a 6-hour dosing interval is derived from only normal healthy volunteers. Thirty-three patients with ischemic heart disease, ages 30-88 years, were administered 1-4g/24 hours (mean dose 34 mg/kg/day) of PROCAN-SR in 4 equally divided doses on a Q6H schedule. After achievement of steady-state equilibrium drug concentration, procainamide and N-acetylprocainamide levels were determined by high-performance liquid chromatography on sera obtained from blood samples drawn 2, 3.5 and 5 hours after an oral dose. Mean maximal procainamide and N-acetylprocainamide serum concentrations were 4.6 +/- 1.8 microgram/ml and 4.2 +/- 2.1 micrograms/ml respectively. Mean minimal concentrations were 3.5 +/- 1.7 microgram/ml and 3.6 +/- 2.0 micrograms/ml respectively. The mean change in drug concentration was small (1.1 microgram/ml procainamide and 0.6 microgram/ml N-acetylprocainamide) with procainamide and N-acetylprocainamide concentrations varying only by 27 and 15 percent respectively. These data demonstrate in a population of patients with ischemic heart disease, that Q6H dosing with a sustained release procainamide hydrochloride preparation (PROCAN-SR, Parke-Davis) is associated with only a small acceptable variation between maximal and minimal serum procainamide and N-acetylprocainamide concentrations. This preparation should, therefore, offer greater patient convenience and compliance without sacrificing antiarrhythmic efficacy.
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124
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Follath F, Ganzinger U, Schuetz E. Reliability of antiarrhythmic drug plasma concentration monitoring. Clin Pharmacokinet 1983; 8:63-82. [PMID: 6404580 DOI: 10.2165/00003088-198308010-00004] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Measurement of drug levels is becoming increasingly popular to optimise the dosage of various drugs. In the case of antiarrhythmic drugs, the narrow therapeutic margin of most of these agents and a direct relationship between their pharmacological effects and plasma concentrations would justify more widespread use of monitoring. Optimum plasma concentration ranges have been described for lignocaine (lidocaine), procainamide, quinidine and, more recently, also for disopyramide, mexiletine, tocainide and other new antiarrhythmics. A critical analysis of the original data shows, however, that therapeutic and toxic levels are not so well defined as often assumed: small numbers of patients, marked interindividual variability, sometimes inadequate documentation of arrhythmias and lack of standardised blood sampling characterise many of these studies. Uncertainty about the reliability of concentration-effect relationships also arises when active drug metabolites are identified or there are marked concentration-dependent changes of drug protein-binding. In addition, abolition of various types of arrhythmias might require different drug concentrations. Nevertheless, therapeutic monitoring can be of practical value in patients with life-threatening ventricular arrhythmias and can also greatly facilitate dosage adjustment in cases with renal hepatic or severe cardiac failure. For a correct interpretation of drug levels, the time of blood sampling, dosage regimen, duration of treatment, pharmacokinetic principles, and the clinical condition of the patient must be taken into account. Further studies are needed to define the optimum therapeutic range for several drugs and to evaluate the usefulness of plasma concentration measurements in routine antiarrhythmic treatment.
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125
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Ross DL, Sze DY, Keefe DL, Swerdlow CD, Echt DS, Griffin JC, Winkle RA, Mason JW. Antiarrhythmic drug combinations in the treatment of ventricular tachycardia. Circulation 1982; 66:1205-10. [PMID: 6814784 DOI: 10.1161/01.cir.66.6.1205] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Combinations of antiarrhythmic drugs are frequently used to treat refractory ventricular tachycardia (VT), but few scientific data support this practice. We examined the efficacy and electrophysiology of 110 antiarrhythmic drug combination trials at electrophysiologic study in 74 patients with recurrent ventricular tachycardia. Lidocaine was combined with quinidine in 33 trials, procainamide in 22 and encainide in 20. Propranolol was combined with quinidine in 17 trials, procainamide in 12 and encainide in six. All individual drugs tested (except propranolol, which was usually not tested individually) had failed at electrophysiologic study or clinically in the presence of usually accepted plasma concentrations. Lidocaine in combination with quinidine was effective in 3% of the trials, with procanamide in 5% and with encainide in none of the trials. Propranolol in combination with quinidine was effective in 18% of the trials, with procainamide in 17% and with encainide in none of the trials. The electrophysiologic effects of the tested drug combinations were dominated by the individual effects of the type 1 antiarrhythmic agents. We conclude that the tested antiarrhythmic drug combinations are infrequently effective in preventing VT induction at electrophysiologic study when each agent has failed individually. The addition of lidocaine or propranolol to quinidine, procainamide or encainide does not produce significant synergistic or new effects on the electrophysiologic variables analyzed.
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