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A 21-day, open-label, multisite, dose escalation study comprising three demographic groups (children, adolescents, and adults) was performed to determine the pharmacokinetics and tolerability of orally administered buspirone. Thirteen children and 12 adolescents with anxiety disorder and 14 normal healthy adults were escalated from 5 to 30 mg buspirone bid over the 3-week study. Pharmacokinetic analysis revealed that buspirone was rapidly absorbed in all study groups, reaching peak levels at about 1 hour after administration. Peak plasma buspirone concentrations (Cmax) were highest in children and lowest in adults at all three dose levels (7.5, 15, 30 mg bid). However, 1-pyrimidinylpiperazine (1-PP), the primary metabolite of buspirone, exhibited a different plasma concentration-time profile; Cmax was significantly higher in children than in either adolescents or adults at all concentrations. In addition, TAUC0-T for 1-PP was significantly higher in the children cohort relative to adolescents and adults. Buspirone was generally safe and well tolerated at doses up to 30 mg bid in adolescents and adults and most of the children. The most frequently reported adverse events in children and adolescents were lightheadedness (68%), headache (48%), and dyspepsia (20%); 2 children withdrewfrom the study at the higher doses (15 mg and 30 mg bid) due to adverse effects. In adults, the most common adverse effect was somnolence (21.4%); lightheadedness, nausea, vomiting, and diarrhea were also reported, although these were mild in intensity.

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Avitriptan, a selective 5-HT1-like receptor agonist, is an effective compound for the treatment of migraine headaches with a prolonged duration of response. A double-blind, placebo-controlled, parallel-group, ascending-dose study in 24 healthy subjects was designed to assess the safety, tolerance, pharmacokinetics, and pharmacodynamics of avitriptan. This antimigraine drug was administered as two consecutive constant-rate IV infusions at three dose levels (12.7, 25.3, and 38.0 mg), which were targeted to produce plasma concentrations in and above the therapeutic range. The best fitting of the plasma concentration-time data was obtained by using a triexponential function yielding a terminal t1/2 of 8 hours. The areas under the plasma concentration versus time curves were proportional to dose, indicating linear pharmacokinetics. Moreover, the clearance and steady-state volume of distribution values were independent of the dose. The change in pulse rate and supine systolic and diastolic blood pressure was determined as pharmacodynamic effects of avitriptan. A "threshold log-linear" model, which accounts for the linear increase in pharmacodynamic effect with the log of plasma concentrations when the latter was higher than a certain threshold value, adequately described the pharmacodynamic data. The threshold plasma drug concentrations for the pulse rate and the diastolic and systolic blood pressure were 14, 74, and 161 ng/ml, respectively. Overall, avitriptan has consistent, linear pharmacokinetics and increases systolic and diastolic blood pressure in a predictable manner at a higher plasma concentration. However, this drug does not produce a significant change in pulse rate at the dose levels (12.7-38 mg) evaluated in this study.

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We examined the effects of avitriptan, a 5-hydroxytryptamine 1-like (5HT1) receptor agonist for the treatment of migraine, in patients with medicated, controlled, mild to moderate hypertension relative to placebo and sumatriptan. The study was randomized, double-blinded, placebo-controlled, and 4-way crossover in design. Twenty patients (12M, 8F) participated. As required by protocol, all were stable on medications for mild to moderate hypertension, with a supine diastolic blood pressure of < 95 mmHg. Qualified subjects were randomized to receive oral administration of either 75 or 150 mg of avitriptan, 100 mg sumatriptan or placebo during the four treatment visits. Supine blood pressure and pulse rates were recorded up to 24 h after drug administration. Avitriptan 150 mg significantly increased peak diastolic and systolic blood pressure, and mean arterial pressure compared to placebo and sumatriptan 100 mg (p < 0.05). Only those hypertensive patients receiving medication for hypertension should receive anti-migraine medications, such as avitriptan, which are 5HT1-like receptor agonists.

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Avitriptan (BMS-180048) is a 5-HT1-like receptor agonist for the treatment of migraine. This double-blind, placebo-controlled, randomized, parallel-group study evaluated the pharmacokinetics, safety, and preliminary efficacy of avitriptan in patients with migraine during migrainous and pain-free states. Patients met the IHS criteria for migraine with or without aura and suffered one to six migraines per month for at least 1 year. Patients in a clinic experiencing a migraine headache received avitriptan 75 mg, 150 mg, or 200 mg or matching placebo capsules. Blood samples were obtained before and 0.25, 0.75, 1, 1.5, 2, 2.5, 3, 4, 5, and 6 hours after dosing. Headache intensity was rated before and up to 6 hours after dosing. Seven to 30 days after the inclinic treatment, patients returned in a pain-free state for the same study medication. All pharmacokinetic and safety measures were repeated. Forty-eight patients (9 men and 39 women) participated. Peak plasma concentrations of avitriptan were achieved 1 to 2 hours following dosing in migraine and pain-free states for all doses. The pharmacokinetics of avitriptan were proportional to dose during a migraine attack over the 75- to 200-mg dose range. The 150- and 200-mg doses of avitriptan demonstrated a greater decrease in headache intensity scores at 2 hours postdose. The most common adverse event was paresthesia. Thus, avitriptan was rapidly absorbed, well tolerated, and demonstrated preliminary efficacy in this population.

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In the course of evaluating the safety and efficacy of an investigational compound for acute migraine headaches, a large number of patients received placebo at a single site, offering the opportunity to characterize subjective and clinical physiologic responses of migraine patients to placebo in a controlled environment. In a single-site, double-blind, placebo-controlled study, 67 patients reported to the clinic while suffering a moderate to severe acute migraine headache and received oral placebo. For 6 hours after treatment, a continuous electrocardiogram (ECG) was performed, and headache severity, adverse events, and vital signs were recorded. Patients returned and repeated the procedure when free from pain. A headache was considered to be improved if its severity dropped to "mild" or "none." Twenty-five patients (37%; 95% CI: 26% to 50%) experienced headache improvement within 2 hours of receiving placebo, and 32 patients (48%: 36% to 60%) improved within 4 hours. There were no clinically important ECG changes during the migraine visit, and there were no clinically relevant differences in vital signs between the migraine and pain-free visits. Thus, a substantial placebo response occurs in migraine headache. Hemodynamic and ECG parameters are unchanged between migraine and pain-free states.

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Potential interactions between nefazodone (200 mg every 12 hours) and propranolol (40 mg every 12 hours) were assessed in 18 healthy male volunteers in an open-label, randomized, three-way crossover study. The nature, frequency, and severity of adverse events during coadministration of nefazodone and propranolol were similar to those observed with either treatment alone. There were no clinically significant effects on vital signs, electrocardiographic results, or laboratory parameters. With coadministration, the maximum peak concentration (Cmax) and area under the concentration-time curve over the dosing interval (AUC tau) of propranolol decreased 29% and 14%, respectively; Cmax and AUC tau of 4-hydroxy-propranolol decreased 15% and 21%, respectively. Despite decreased plasma concentrations of the beta-antagonists, the reduction in exercise-induced tachycardia and post-exercise double product was slightly greater with coadministration than with propranolol alone. Administration of nefazodone alone did not significantly affect either pharmacologic parameter. The pharmacokinetics of nefazodone and its metabolites were largely unaffected during coadministration. Coadministration of propranolol and nefazodone results in modest pharmacokinetic inequivalencies, but no clinically significant alterations of the pharmacodynamics of propranolol.

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Five patients with NYHA Class III CHF received 5 mg of fosinopril on each of 4 days. Hemodynamics were measured with a Swan-Ganz catheter after dosing on day 1. Measurements of plasma fosinoprilat, ACE activity, renin, and aldosterone were obtained. An Emax model was used to fit the effect-site concentration and mean arterial pressure change. A linear model was used to fit the effect-site concentration and the pulmonary artery wedge pressure (PAWP) change. At steady state on day 4, AUC0-24 was 1668 +/- 476 ng.hr/mL and Cmax was 143.5 +/- 33.6 ng/mL. The mean elimination half-life of fosinoprilat was 11.3 +/- 0.7 hours, and median Tmax occurred at 3 hours, corresponding to maximum plasma ACE inhibition. Plasma renin activity was unchanged, and mean plasma aldosterone level declined. Emax modeling using fosinoprilat concentrations and mean arterial pressure showed good prediction of the pharmacodynamic effects from the effect-site concentration. A linear relationship was observed between the effect-site concentrations of fosinoprilat and PAWP. When expressed in an Emax model, the pharmacodynamic actions of fosinopril in patients with CHF are a reflection of its pharmacokinetics.

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Nefazodone, an antidepressant with serotonin and norepinephrine receptor modulating activity, is highly protein bound and eliminated by oxidative metabolism. This study evaluated the potential for clinically significant drug interactions with warfarin and nefazodone coadministration. Eighteen subjects received warfarin daily for 14 days, achieving steady-state warfarin concentrations and a stable prothrombin ratio. Nefazodone 200 mg every 12 hours (n = 12) or placebo every 12 hours (n = 6) was then added to the daily warfarin dose for the next 7 days in a double-blind, randomized design. No serious or unexpected adverse events or events suggestive of abnormal bleeding occurred during coadministration. The addition of nefazodone had no effect on the unbound fraction of total warfarin in plasma or on the steady-state pharmacokinetics of R-warfarin based on within-subject or comparison to placebo-treated subjects. The steady-state AUCTAU over the dosing interval and Cmax of S-warfarin decreased by 12%; however, this change is clinically insignificant because the prothrombin ratio and bleeding time remained unchanged. The steady-state minimum concentrations for nefazodone and metabolites, achieved on coadministration day 3, were typical of healthy men treated with this nefazodone dosage. In conclusion, warfarin and nefazodone coadministration was safe and well-tolerated with no clinically significant interactions.

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The time to peak antihypertensive effect and the trough-to-peak ratio were determined in 64 Caucasian patients (19 men, 45 women) with mild to moderate hypertension [supine diastolic blood pressure (DBP) 95 to 115 mmHg]. They received placebo or fosinopril 10, 20, or 40 mg once daily for 4 weeks. The study consisted of a 4-week placebo lead-in, 4 weeks' double-blind treatment, and a 1-week placebo washout period. Vital signs were determined biweekly before dosing, and blood pressures were measured every 1 to 2 h during two 27-h periods at the beginning and end of treatment. After the first and last doses of all three regimens, the peak effect on blood pressure occurred 5 to 7 h after all three dosages. Neither peak nor trough blood pressure changes showed a clear dose-response relationship. Trough to peak ratios for the first dose, corrected for placebo effects, were 79% for fosinopril 10 mg, 48% for fosinopril 20 mg, and 74% for fosinopril 40 mg, and the trough-to-peak ratios for the last dose were 41% for fosinopril 10 mg, 32% for fosinopril 20 mg, and 44% for fosinopril 40 mg. In the 38 responders among the 48 patients receiving fosinopril (supine DBP decrease of at least 5 mmHg at 24 h postdose), trough-to-peak ratios ranged from 50 to 81%, and the range indicates that fosinopril is efficacious when administered once daily. Adverse effects were mild to moderate, and no patient discontinued treatment. Changes in the laboratory test results, electrocardiograms, or the results of physical examinations were unremarkable.(ABSTRACT TRUNCATED AT 250 WORDS)

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We determined the ability of the thromboxane A2 antagonist SQ 29,548 or diltiazem to enhance postischemic myocardial function and if the effects of these compounds were occurring during occlusion or reperfusion periods. Anesthetized open-chest dogs were pretreated with i.v. saline, SQ 29,548 (0.20 mg/kg + 0.20 mg/kg/hr) or diltiazem (0.18 mg/kg) 15 min before the left anterior descending coronary artery was occluded. In another group, animals were given saline, SQ 29,548 or diltiazem 1 min before reperfusion. The occlusion was maintained for 15 min and reperfusion instituted for 5 hr. Subendocardial segmental shortening was monitored throughout the experiment using sonomicrometry. Left anterior descending coronary artery occlusion resulted in marked systolic bulging to similar levels in all groups. Upon reperfusion, function returned immediately but, after several min, hypokinesia existed in saline-treated animals. At 5-hr postreperfusion, percentage of shortening returned to only 20% of base-line values in saline-treated animals. Both diltiazem and SQ 29,548 pretreatment resulted in significant (P less than .05) improvements in function such that at 5-hr postreperfusion, shortening returned to 60% of base-line values. When given immediately before reperfusion, SQ 29,548 still resulted in significant protection of function, although this occurred much later compared to pretreated animals. Diltiazem did not improve function when given immediately before reperfusion. SQ 29,548 improves reperfusion function and, thus by inference, thromboxane A2 may play a role in postischemic hypokinesia and some of its protective effects may occur during reperfusion. Diltiazem seems to protect reperfusion function only when present during ischemia per se.

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The antiarrhythmic, antifibrillatory activities and the ability of SQ 26,533 to reduce infarct size were investigated in the canine models of reperfusion arrhythmias. In model 1, halothane-anesthetized dogs were subjected to acute occlusion of left circumflex coronary artery (LCX) for 30 min followed by reperfusion. SQ 26,533 infused at 50 micrograms/kg/min for 45 min significantly reduced (78%) the incidence of ventricular ectopic beats during the 30-min ligation of LCX. In addition, four of seven dogs (57%) survived after reperfusion, in contrast to 100% mortality observed in untreated animals. In model 2, left anterior descending artery under pentobarbital anesthesia was occluded for 20 min and released. SQ 26,533 (2.5 mg/kg i.v.) given 1 hr before occlusion significantly reduced (81%) ventricular ectopic beats during acute occlusion and four of five animals (80%) survived left anterior descending artery reperfusion, unlike saline controls (100% mortality). Similar efficacy was seen in a feline model of reperfusion arrhythmias. The model 3 animals under pentobarbital anesthesia were occluded for 60 min followed by reperfusion of the LCX in the presence of critical stenosis. SQ 26,533 (2.5 mg/kg every 90 min) given 50 min after LCX occlusion not only resulted in a significant reduction (91%) of postreperfusion ventricular ectopic beats for the entire 5-hr observation period but also significantly reduced (42%) the infarct size at 24 hr. Antiarrhythmic doses of SQ 26,533 caused minimal hemodynamic changes, except for a marked decrease in heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

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The hemodynamic effects exerted by two chemically dissimilar calcium antagonists (tiapamil and nifedipine) were studied in anesthetized dogs during control conditions, following critical stenosis of the left circumflex coronary artery, and in the presence of beta-receptor blockade with nadolol (1 mg/kg). Dose-dependent hemodynamic changes were observed following the intravenous administration of three different doses of tiapamil (0.5, 1.0, and 2.0 mg/kg) and nifedipine (2.5, 5.0, and 10.0 micrograms/kg) during control conditions. In the presence of critical coronary stenosis, tiapamil and nifedipine produced similar magnitudes of decreases in blood pressure and changes in heart rate. Tiapamil produced paradoxic increases in left ventricular (LV) dP/dt and contractile force since these changes were accompanied by a slight decrease in heart rate. Nifedipine, unlike tiapamil, resulted in reflex increases in heart rate and myocardial contractility in response to reduction in the afterload. Also, nifedipine, unlike tiapamil, produced relatively minor changes in the coronary flow of the unoccluded left anterior descending coronary artery. In the presence of nadolol and critical stenosis, both agents produced markedly different hemodynamic responses. In the tiapamil series, three out of five dogs died due to severe cardiodepression consisting of bradycardia, hypotension, reduced myocardial contractility, and coronary blood flow. No mortality was observed in the nifedipine series since the cardiac function was adequately maintained in the presence of beta-blockade. Our results are in close agreement with the clinical observations, indicating a much higher incidence of dangerous drug interactions with combined use of verapamil-like compounds (e.g., tiapamil) with beta-blockers than with nifedipine, especially in patients with coronary artery disease and AV conduction disturbances.

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