Bunazosin in patients with impaired hepatic or renal function

Clinical pharmacokinetics of vasodilators. Part II

Stimulating cardiac beta 1-adrenoceptors with oxyfedrine causes dilatation of coronary vessels and positive inotropic effects on the myocardium. beta 1-adrenergic agonists increase coronary blood flow in nonstenotic and stenotic vessels. The main indication for the use of the phosphodiesterase inhibitors pamrinone, mirinone, enoximone and piroximone is acute treatment of severe congestive heart failure. Theophylline is indicated for the treatment of asthma, chronic obstructive pulmonary disease, apnea in preterm infants ans sleep apnea syndrome. Severe arterial occlusive disease associated with atherosclerosis can be beneficially affected by elcosanoids. These drugs must be administered parenterally and have a half-life of only a few minutes. Sublingual or buccal preparations of nitrates are the only prompt method (within 1 or 2 min) of terminating anginal pain, except for biting nifedipine capsules. The short half-life (about 2.5 min) of nitroglycerin (glyceryl trinitrate) makes long term therapy impossible. Tolerance is a problem encountered with longer-acting nitric oxide donors. Knowledge of the pharmacokinetic properties of vasodilating drugs can prevent a too sudden and severe blood pressure decrease in patients with chronic hypertension. In considering the administration of a second dose, or another drug, the time necessary for the initially administered drug to reach maximal efficacy should be taken into account. In hypertensive emergencies urapidil, sodium nitroprusside, nitroglycerin, hydralazine and phentolamine are the drugs of choice, with the addition of beta-blockers during catecholamine crisis or dissecting aortic aneurysm. Childhood hypertension is most often treated with angiotensin-converting enzyme (ACE) inhibitors or calcium antagonists, primarily nifedipine. Because of the teratogenic risk involved with ACE inhibitors, extreme caution must be exercised when prescribing for adolescent females. The propagation of health benefits to breast-fed infants, combined with more women delaying pregnancy until their fourth decade, has entailed an increase in the need for hypertension management during lactation. Low dose hydrochlorothiazide, propranolol, nifedipine and enalapril or captopril do not pose enough of a risk of preclude breastfeeding in this group. The most frequently used antihypertensive agents during pregnancy are methyldopa, labetalol and calcium channel antagonists. Methyldopa and beta-blockers are the drugs of choice for treating mild to moderate hypertension. Prazosin and hydralazine are used to treat moderate to severe hypertension and hydralazine, urapidil or labetalol are used to treat hypertensive emergencies. The use of overly aggressive antihypertensive therapy during pregnancy should be avoided so that adequate uteroplacental blood flow is maintained. Methyldopa is the only drug accepted for use during the first trimester of pregnancy.

Disposition, Elimination and Haemodynamic Effects of Gallopamil in Patients with Fatty Liver Disease

Twenty-one hypertensive patients were treated orally with 50mg gallopamil in a sustained-release formulation once daily for 1 week. 11 patients had a normal liver function (antipyrine clearance 41.2 ± 2.8 ml/min; mean ± SD), while 10 patients had fatty liver disease (antipyrine clearance 32.3 ± 1.4 ml/min). Maximum plasma concentrations of gallopamil were 15.2 (7.9 to 29.3) µg/L (geometric mean; 95% confidence interval) in patients with normal and 16.8 (8.7 to 32.5) µg/L in those with impaired hepatic function (p > 0.05). The elimination half-life was 8.8 hours in patients with normal liver function and 9.2 hours in patients with fatty liver disease (median, p > 0.05). No significant differences were found between patients with and without concomitant liver disease with regard to the effects of gallopamil on heart rate, PQ-time and blood pressure. First degree AV-block developed during treatment with gallopamil in one patient with fatty liver disease and in another with normal liver function. The AV-block in the patient with impaired hepatic function was considered to be severe (PQ-time 270ms). In conclusion, kinetic parameters of patients with fatty liver disease did not differ significantly from those of subjects with normal liver function.