PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Verapamil”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1991

Treatment with verapamil during and after an acute myocardial infarction: a review based on the Danish Verapamil Infarction Trials I and II. The Danish Study Group on Verapamil in Myocardial Infarction.

The effect of verapamil on death and reinfarction after an acute myocardial infarction was studied in two double-blind, randomized, placebo-controlled multicenter trials, the Danish Verapamil Infarction Trials I and II (DAVIT I and II). The studies demonstrated that verapamil 360 mg/day from the 2nd week after an acute myocardial infarction, prevented death and reinfarction. Meta-analyses of the results of DAVITs I and II resulted in a reduction of pooled ratios of 22% (95% confidence limits 1-37, p = 0.04) for death, 21% (5-35, p = 0.02) for first major events (first reinfarction or death), and 27% (6-43, p = 0.02) for first reinfarctions. The effect of verapamil was to prevent myocardial ischemia and reduce sudden death and reinfarction. It is concluded that long-term treatment with verapamil after an acute myocardial infarction may be recommended with the object of reducing overall mortality, major events and reinfarction.

Arrhythmias, Cardiac↗
PubMed1992

Comparative efficacy, safety and pharmacokinetics of verapamil SR vs verapamil IR in hypertensive patients.

The antihypertensive effects of the regular immediate release formulation of verapamil (verapamil IR) and the newer sustained release formulation of verapamil (verapamil SR) were compared in Hispanic patients with untreated essential hypertension. Verapamil IR was given in 3 divided doses (80 or 160mg 3 times daily) and verapamil SR was given either as a single daily dose of 240mg or as 240mg every 12 hours. With both formulations there was a significant reduction in systolic (SBP) and diastolic blood pressure (DBP); a greater lowering of BP was observed with verapamil 480 mg/day than with 240 mg/day. With verapamil SR 480 mg/day, 91% of patients had reductions in SBP and DBP greater than 20 and 15mm Hg, respectively. In addition, 83% of patients reached normotension. With the lower dose (240mg once daily), 83% of patients had decreases in DBP greater than 10mm Hg and 73% of patients achieved normotension. Comparable effects were achieved with verapamil IR. With verapamil IR there was a more rapid fall in BP which peaked 3 to 4 hours postdose, whereas with verapamil SR a more gradual and sustained BP reduction was observed. Only small changes in heart rate (HR) were observed with verapamil IR and verapamil SR. For verapamil SR, the mean increase in HR was 5 beats/min (to 80 beats/min) and the mean decrease in HR was 13 beats/min (to 62 beats/min). Both verapamil SR and verapamil IR prolonged the PR interval of the ECG. An equal degree of PR prolongation was observed with 240 and 480 mg/day. The incidence of side effects (headache, palpitations, dizziness and flushing) was dose dependent, decreased with continuous treatment and was much higher with verapamil IR than with verapamil SR. Steady-state plasma verapamil concentrations were monitored. Compared with verapamil IR, verapamil SR produced a more gradual rise and a more sustained elevation of plasma verapamil and norverapamil concentrations. Comparable trough verapamil concentrations (Cmin) were observed with verapamil IR (98 micrograms/L) and SR (81 micrograms/L); morning Cmin verapamil concentrations were higher than daytime Cmin values. The normalised area under the plasma concentration-time curve (AUC) and maximum concentration (Cmax) were 10 to 20% greater for verapamil IR than SR. The 2-fold increase in oral dose produced a 2.2- and 2.4-fold increase in AUC for verapamil IR and SR, respectively, associated with a 20% reduction in metabolism to norverapamil. Fasting increased the rate and extent of absorption of verapamil.(ABSTRACT TRUNCATED AT 400 WORDS)

Blood Pressure↗
PubMed1975

The pharmacodynamics of orally taken verapamil and verapamil retard as judged by their negative dromotropic effects.

The widely recognized, negative dromotropic effects of alpha-isopropyl-alpha-[N-methyl-N-homaveratryl)-gamma-aminopropyl]-3-4-dimethoxyphenylacetonitrile (verapamil, Isoptin) on arterio-venous (A-V) nodal conductions were studied using long-term atrial stimulation (AS) in 7 healthy volunteers whose mean age was 30 years. A control group consisting of three of the volunteers who underwent long-term atrial stimulation without medication was established. Since an isolated, well-known drug effect was studied over a long period of time, it was felt that this was an acceptable method for reaching valid pharmacodynamic conclusions. Atrial stimulation was carried out at hourly intervals up to 14-16 h and continued to the highest possible rate without the occurrence of 2nd degree A-V block before and following oral application of verapamil, 240 mg. The stimulus-Q (S-Q) prolongation at increased pace rates was compared to the control. Verapamil retard was tested in a similar course of investigation the following day. The results clearly demonstrated that both forms of verapamil are effective when taken orally. Verapamil acts 2 h after oral application. The peak effectiveness of the drug is found at 5 h and at this point A-V block can occur at low atrial stimulated rates. The effect of verapamil retard is obvious only after 6 h but is still apparent after 14 h and it remains constant with no peak in effectiveness. Characteristics of the resulting regressions allow to distinguish the effect of verapamil on A-V conduction from influences that might be mediated by the diurnal changes in tone of the autonomic nervous system only. The effect of verapamil after oral application is more pronounced with higher heart rates. The pharmacodnaymics of verapamil evaluated with regard to a single well-known pharmacological effect, have not necessarily to be identical with the pharmacokinetics and the bioavailability of the drug.

Adult↗
PubMed1992

[Verapamil therapy improves the prognosis after acute myocardial infarction. A review over the Danish studies of verapamil therapy during and after acute myocardial infarction].

The effect of verapamil therapy in a dosage of 120 thrice daily on the mortality and re-infarction from the time of admission and for the subsequent six months was investigated in a double-blind, randomized, placebo-controlled, multicentre investigation (The Danish Verapamil Infarction Trial (DAVIT I)). Seven hundred and seventeen patients were treated with verapamil and 719 with placebo. The mortalities after six months were 12.8% in the verapamil group and 13.9% in the placebo group (NS) and re-infarction occurred in 7.0% and 8.3%, respectively (NS). The effect of verapamil on the mortality and major events, i.e. death or the first re-infarction from the second week after an acute myocardial infarction was investigated in a double-blind, randomized, placebo-controlled, multicentre investigation (DAVIT II) in which 878 patients commenced treatment with verapamil in a dosage of 360 mg daily and 897 patients received a placebo. This treatment was continued for up to 18 months, on an average for 16 months. Ninety-five patients died and 146 major events were registered in the verapamil group while 119 died and 180 major events occurred in the placebo group. The 18 months mortality rates were 11.1 and 13.8% (hazard ratio 0.80, 95% confidence limits 0.63-1.05, p = 0.11) and the major event rates were 18.0 and 21.6% (0.80, 0.64-0.99, p = 0.03) in the verapamil and placebo groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Denmark↗
PubMed1991

Hydrochlorothiazide and verapamil in the treatment of hypertension. The Verapamil Versus Diuretic (VERDI) Trial Research Group.

The efficacy and tolerability of hydrochlorothiazide, sustained-release verapamil, and their combination was compared in patients with mild to moderate hypertension. The design was a multicenter, randomized, double-blind clinical trial with a single-blind placebo baseline period of 2 weeks. Three hundred sixty-nine patients with a diastolic blood pressure of 95-120 mm Hg were included. Treatment consisted of 12.5 mg of hydrochlorothiazide once daily, then 25 mg once daily, and finally 25 mg twice daily; the other group received verapamil at a dose of 120 mg once daily, then 240 mg once daily, and finally 240 mg twice daily. Patients not achieving target blood pressure (less than 90 mm Hg diastolic) were given the combination of hydrochlorothiazide and verapamil, that is, 25 and 240 mg once daily and twice daily. During all time points during the study patients receiving verapamil achieved target blood pressure more often than patients receiving hydrochlorothiazide (after 8 weeks, 57.7 and 42.7%; after 24 weeks, 46.8 and 26.4%; and after 48 weeks, 44.8 and 24.7%, respectively). Adding verapamil to hydrochlorothiazide was more effective in lowering blood pressure than adding hydrochlorothiazide to verapamil. The number of treatment withdrawals was essentially the same with the two drugs. Therefore, in the doses currently used in antihypertensive treatment, verapamil was more effective than hydrochlorothiazide as a single agent and in combination in mild to moderate hypertension.

Adult↗
PubMed1991

Changes in calcium homoeostasis and bone formation in patients recovering from acute myocardial infarction: effect of verapamil treatment. Danish Study Group on Verapamil in Myocardial Infarction.

The effect of the calcium antagonist verapamil on calcium homoeostasis and bone metabolism has been investigated in a double-blind randomized placebo-controlled study. Ten patients randomized to verapamil 120 mg t.i.d. and 9 patients randomized to placebo in The Danish Verapamil Infarction Trial II took part in the study. Bone formation, estimated by 24-h whole body retention of diphosphonate (WBR), osteocalcin, alkaline phosphatase and calcium metabolic indices, was recorded before the start of medication and after 1 and 6 months of treatment. Baseline calcium metabolic variables were not significantly different between the two study groups. There were no significant differences in WBR (0.38 vs 0.37), osteocalcin level (8.2 vs 8.0 micrograms/l) or alkaline phosphatase (218 vs 200 U/l) after treatment for 6 months with verapamil compared to placebo. Serum PTH, calcium and phosphate levels were also not affected by verapamil. The results suggest that prolonged treatment with clinical doses of verapamil does not affect indices of calcium and bone metabolism in humans.

Alkaline Phosphatase↗
PubMed1991

Treatment with verapamil after an acute myocardial infarction. Review of the Danish studies on verapamil in myocardial infarction (DAVIT I and II).

The effect of verapamil on death, reinfarctions, and major events, i.e. death or reinfarction after a myocardial infarction has been investigated in 2 Danish double-blind placebo-controlled verapamil infarction trials (DAVIT I and II). DAVIT I was an early intervention trial that demonstrated a statistically nonsignificant reduction in mortality and reinfarction after 6 months of treatment. DAVIT II was a later intervention trial that demonstrated a nonsignificant reduction in the 18-month mortality rate [p = 0.11, hazard ratio 0.80; 95% confidence limits (CL) 0.61 to 1.05], a significant reduction in the reinfarction rate (p = 0.04, hazard ratio 0.77; CL 0.58 to 1.03), and in the major event rate (p = 0.03, hazard ratio 0.80; CL 0.64 to 0.99) in the verapamil group compared with the placebo group. In patients without heart failure in the coronary care unit, a statistically significant reduction in the 18-month mortality rate (p = 0.02, hazard ratio 0.64; CL 0.44 to 0.94), the reinfarction rate (p = 0.02, hazard ratio 0.67; CL 0.46 to 0.97), and the major event rate (p = 0.01, hazard ratio 0.70; CL 0.52 to 0.93) was observed in the verapamil group compared with the placebo group. No significant differences were found in patients with heart failure. Meta-analyses of DAVIT I (for patients alive at day 8) and DAVIT II showed a statistically significant reduction in the odds ratio of mortality (22%), reinfarctions (27%), and the major event rate (21%) in verapamil-treated patients. It is concluded that long term treatment with verapamil after an acute myocardial infarction is associated with a significant reduction in overall mortality, major events, and reinfarctions, with the greatest effect in patients without heart failure.

Angina Pectoris↗
PubMed1991

Effect of verapamil on ischemia and ventricular arrhythmias after an acute myocardial infarction: prognostic implications. The Danish Verapamil Infarction Trial II Study Group.

This article is a review of presented subsets of the Danish Verapamil Infarction Trial II (DAVIT II) regarding the effect of verapamil on postinfarction ischemia, ventricular arrhythmias, and heart rate (HR), and the prognostic implications of these findings. Patients underwent Holter monitoring for 24-48 h at 1 week, i.e., before randomization to long-term treatment with placebo or verapamil, and after 1 month and about 1 year of study treatment. Ischemia: 18% of the patients had transient ST-segment deviation before randomization; 24% of the placebo- and 8% of the verapamil-treated patients (p = 0.04) showed ischemia after 1 month; and after 1 year, the figures were 26 and 4%, respectively (p = 0.02). The 18-month major event rate, i.e., first reinfarction or death, in patients with ischemia before randomization were 40 and 23.8% in patients without ischemia (p = 0.06). Arrhythmias: In the placebo group the prevalence and incidence of many ventricular ectopic beats (VEBs), i.e., more than 10 VEBs/h, increased significantly during the first years after infarction; this was not the case in the verapamil patients group. The mean HR was significantly reduced by verapamil treatment after 1 month and after 16 months of treatment. Multivariate analysis demonstrated the presence of more than 10 VEBs/h only early (i.e., 1 week) but not late (i.e., 1 month) after infarction, to be an independent predictor of major events during 18 months' follow-up observation. A HR above 80 beats/min independently predicted major events when appearing both early and late after infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1992

The significance of myocardial ischaemia and verapamil treatment on the prevalence of supraventricular tachyarrhythmias in patients recovering from acute myocardial infarction. Danish Study Group on Verapamil in Myocardial Infarction.

Twenty-four hour Holter monitoring and symptom-limited exercise testing were carried out prior to discharge in 157 patients recovering from acute myocardial infarction. Supraventricular arrhythmias (SVT) during Holter monitoring were recorded in 15%, and ST segment depression during exercise in 27%. No association between exercise-provoked ischaemia and SVT was found in the late hospital phase of myocardial infarction. After the tests, patients were double-blindly randomized to treatment with verapamil 120 mg t.i.d. or placebo. One month after randomization 24 h Holter monitoring was repeated in 125 patients (verapamil = 63, placebo = 62). At one month a significantly increased incidence of SVT was found in the placebo group (25%) compared to the verapamil-treated patients (9%) (P = 0.04). The increased prevalence in the placebo group was mainly due to an increased incidence of SVT in patients with exercise-induced ischaemia (P = 0.03). This increment was blurred in the verapamil group. In conclusion, the prevalence of SVT increases during the first month after myocardial infarction. The increase is most pronounced in patients with residual myocardial ischaemia and seemed to be prevented by treatment with verapamil.

Double-Blind Method↗
PubMed1992

Internally standardized simultaneous assay of verapamil and N-demethyl-verapamil enantiomers in human plasma by means of high performance liquid chromatography.

A high performance liquid chromatographic method with internal analog standardization for the simultaneous assay of the verapamil and N-demethyl-verapamil enantiomers in human plasma after administration of racemic verapamil is described. The method comprises extraction from alkalinized plasma into an n-hexane/2-propanol phase (95:5), separation of the optical antipodes on a chiral phase (Daicel OJ) and quantification by means of fluorescence detection. A detection limit of about 6 pmol was determined for all four enantiomers. Under routine conditions the limit of quantification (variation coefficient < 10%) was about 8 pmol for the (R)- and (S)-enantiomers. The determination method for verapamil and N-demethyl-verapamil enantiomers is not impaired by their known metabolites. The suitability of the method for clinical pharmacology studies is demonstrated with samples obtained from healthy subjects. First results of comparative kinetics studies in humans and various animal species show marked species-dependency with prevailing (R)-enantiomer levels in humans and dogs, and the opposite in rats.

Chromatography, High Pressure Liquid↗
PubMed1977

Determination of verapamil in human plasma by mass fragmentography using stable isotope-labelled verapamil as internal standard.

In the present investigation a mass fragmentographic procedure for the quantitative determination of verapamil in human plasma was developed which makes use of the principle of mass spectrometry and of isotopic dilution: a known amount of isotopically labelled standard ([13C, 2H2]-verapamil) is added to the plasma sample. After an effective extraction procedure the ratio of the main fragments of verapamil (m/e 303) and the labelled standard (m/e 306) is measured by mass fragmentography. The lower limit of detection is at 1 ng/ml for plasma and at 10 pg/injection for pure verapamil. The precision was found to be between 3.4% and 14.4%, depending on the range (32.7 ng/ml and 2.2 ng/ml, resp.) of the concentration of verapamil in plasma.

Chemical Phenomena↗
PubMed1992

Prevalence of transient myocardial ischaemia during the first year after a myocardial infarction. Effect of treatment with verapamil. The Danish Study Group on Verapamil in Myocardial Infarction.

DAVIT-II is a double-blind, randomized, multicentre, placebo-controlled study of long-term treatment with verapamil 360 mg per day administered to patients who have suffered an acute myocardial infarction (AMI). In the present study, comprising a subset of DAVIT-II, 48 h continuous ECG recordings demonstrated transient ST segment deviation indicative of myocardial ischaemia after one week, prior to randomization, in 18% (10 of 57) of the patients. After one month, 24% (11 of 46) of the placebo and 8% (3 of 39) of the verapamil-treated patients (P = 0.04) had myocardial ischaemia; after one year the figures were 26% (9 of 35) and 4% (1 of 27) (P = 0.02), respectively. At 18 months the 'major' event rate in patients who had had ischaemia before randomization was 40% and 23.8% in patients without ischaemia (P = 0.057). In the placebo group, 63% of 91 episodes of ST depression were recorded between 0600 h and 1800 h, and 62% of 26 episodes of ST elevation between 1800 h and 0600 h (P less than 0.001). Nine episodes of ST depression and no episode of ST elevation were recorded in the verapamil-treated patients. In conclusion, 20-25% of post-AMI patients have transient ischaemia; verapamil prevents ischaemia, and a pronounced circadian variation of ST segment deviations can be demonstrated.

Aged↗
PubMed1991

The effect of verapamil on major events in patients with exercise-induced ischemia recovering from acute myocardial infarction: a review. The Danish Study Group on Verapamil in Myocardial Infarction.

The effect of verapamil on death and reinfarction in patients with and without exercise-induced myocardial ischemia after acute myocardial infarction was studied in a double-blind, placebo-controlled multicenter study. Two hundred ninety-eight patients were included. A symptom-limited exercise test was carried out 9 days after the myocardial infarction but before randomization. Forty-four patients with and 111 without exercise-induced ischemia were randomly assigned to verapamil and 39 and 104, respectively, to placebo treatment. The patients were observed for 18 months. The overall 18-month event rate was 12.1%. The lowest event rate was seen in patients with myocardial ischemia and verapamil treatment (9.1%), and the highest in patients with myocardial ischemia receiving a placebo (15.4%), while rates of patients without ischemia were sandwiched in between (12.5 and 12.6%). The differences were not statistically significant.

Blood Pressure↗
PubMed1975

Optical isomers of verapamil on canine heart. Prevention of ventricular fibrillation induced by coronary artery occlusion, impaired atrioventricular conductance and negative inotropic and chronotropic effects.

Effects of optical isomers of verapamil on the canine heart were measured with a pressure catheter in the left ventricle and with the electrocardiogram. 1. Both isomers of verapamil caused impaired atrioventricular conduction. slowed the rate of the sinus pacemaker and depressed the contractile state of the myocardium. (-)-Verapamil was consistently more potent than (+)-verapamil in producing these effects. (-)/(+) potency ratios of 10 and 3 were estimated for atrioventricular blockade and for the negative chronotropic effect, respectively. 2. Negative inotropic effects of 0.06-2.0 mg/kg of (+)-verapamil were determined on hearts paced at constant rate. A similar dose-response relationship could not be established with (-)-verapamil because at concentration higher than 0.06 mg/kg the hearts did not follow the supraventricular driving stimulus. With doses of (-)- and (+)-verapamil which produced the same slowing of the sinus pacemaker rate in spontaneously beating hearts, (-)-verapamil caused greater negative inotropic effects than (+)-verapamil. 3. The following doses of isomers of verapamil reduced the incidence of ventricular fibrillation induced by coronary artery ligation: 0.2 mg/kg (-)-verapamil (P less than 0.001), 0.6 mg/kg (-)-verapamil (P less than 0.001) and 0.6 mg (+)-verapamil (P less than 0.01). 4. Intravenous administration of CaCl2 to dogs treated with either isomer of verapamil restored the contractile state and reversed atrioventricular blockade to sinus rhythm. Dog ventricles under the influence of concentrations of isomers of verapamil which, with normal plasmatic Ca2+-content, prevent fibrillation, consistently fibrillated after coronary artery occlusion when high doses of CaCl2 were administered. 5. The effects of the optical isomers of verapamil may occur predominantly via a blockade of the slow inward Ca2+-current.

Animals↗
PubMed1976

Relationship of antiarrhythmic to inotropic activity and antiarrhythmic qualities of the optical isomers of verapamil.

1. The relationship of antiarrhythmic to inotropic activity of the optical isomers of verapamil was studied by comparing their effects on functional refractory period and force of contraction in the isolated left atrium of the guinea pig and on maximum follow frequency and contractility in the dog heart. To evaluate the antiarrhythmic profile of the optical isomers of verapamil the relationship between threshold voltage and impulse duration in the left atrium of the guinea pig and the antagonistic action against ventricular arrhythmias in the rat were studied. 2. (-)Verapamil is nearly 10 times more effective than (+)verapamil in prolonging the functional refractory period in the isolated left atrium of the guinea pig. 3. In the dog heart (-)verapamil is about 8 times more active in reducing a maximum follow frequency at atrial pacing, as well as spontaneous heart rate and in prolonging PQ-duration. 4. In the guinea pig atrium (+)verapamil shows less negative inotropic activity than its enantiomorph. With (+)verapamil the concentration producing a 25% decrease in contractility is 3.7 times higher than that causing a 25% increase in refractory period. With (-)verapamil these concentrations are identical. 5. In the dog i.v. infusion of the isomers, at a dosage inducing identical reduction of maximum follow frequency, is accompanied by a decrease in left ventricular dp/dtmax with (-)verapamil, whereas with the (+)isomer a significant increase of dp/dtmax is observed at a certain dose level. 6. Because of the higher antiarrhythmic activity of (-)verapamil, the antiarrhythmic profile and the inotropic pattern of the racemic compound are mainly due to this isomer. 7. (+)Verapamil shifts the voltage duration curve of the isolated left atrium of the guinea pig to the right and leads to a significant increase in the chronaxie value. (-)Verapamil has no comparable effects on the excitability of the atrial myocardium. 8. In the intact animal (+)verapamil shows additional antiarrhythmic qualities. Like procainamide, but with higher activity, it antagonizes ventricular arrhythmias (ectopic beats, automaticity and flutter or fibrillation) which can be provoked in the rat by i.v. infusion of aconitine. (-)Verapamil and the racemic compound are ineffective against these ventricular rhythm disorders.

Aconitine↗
PubMed1992

Impact of food on the pharmacokinetics and electrocardiographic effects of sustained release verapamil in normal subjects.

To evaluate the impact of food on the pharmacokinetics and electrocardiographic effects of sustained release (SR) verapamil tablets, 9 healthy men each received 3 single doses of verapamil in a randomized, crossover manner: 10 mg of intravenous verapamil, 240 mg SR verapamil on an empty stomach, and 240 mg SR verapamil with a standardized meal. PR intervals and racemic verapamil serum concentrations were measured serially over 30 hours after administration. The time to peak concentration was longer (7.5 +/- 3.0 vs 4.4 +/- 2.3 hours), resulting in a lower peak verapamil serum concentration (118 +/- 43 vs 175 +/- 50 ng/ml) when SR verapamil was administered with food (p < 0.05). Food tended to decrease the bioavailability of SR verapamil (34 +/- 12 vs 49 +/- 14%), although this difference did not reach statistical significance (p = 0.065). Precipitous or exaggerated release of verapamil from the SR tablet was not observed in any subject during the fasting state. Prolongation of the PR interval paralleled these alterations in serum concentration. The maximal change in the PR interval was greater (21 +/- 8 vs 14 +/- 5%; p < 0.05) when SR verapamil was given in the fasting state. Although an exaggerated verapamil release or effect was not observed, food significantly altered the absorption and electrocardiographic effects of a single dose of SR verapamil. Manipulation of the administration condition may be helpful in achieving desired outcomes.

Administration, Oral↗
PubMed1991

Differences in response to single dose and steady-state therapy with verapamil in stable angina.

Ten patients with stable effort angina were studied in a randomized double-blind and placebo-controlled trial to compare the antianginal efficacy of "acute" and "chronic" (after reaching a steady-state level) treatment with verapamil. Efficacy was assessed by exercise testing after a 120 mg single-dose and at the end of a seven-dose course of 120 mg of verapamil given thrice daily. Three daily exercise tests were performed the first, second and fifth day of the study protocol at 8, 12 and 16 hours. Eight hours after the last dose was given, exercise time increased by 54 +/- 30 sec after a single-dose of verapamil and by 156 +/- 31 sec after seven-doses of verapamil (P less than 0.05 as compared to single-dose verapamil). The time to 1 mm depression of the ST segment increased by 30 +/- 20 sec after a single-dose of verapamil and by 66 +/- 28 sec after seven-doses of verapamil (P less than 0.01 as compared to single dose verapamil). Six of the ten patients became free from angina on treadmill exercise after a seven-dose course of verapamil, but only one patient became free from angina after acute testing with a single-dose of verapamil. It is concluded that several doses of verapamil are required to achieve an optimal anti-ischemic effect, as suggested by the pharmacodynamic properties of this drug. Once steady-state is achieved, the effects of verapamil remain for at least 8 hours, so that an administration schedule of three times daily protects the patient for a 24-hour period.

Administration, Oral↗