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Biomedical subjects

K H Rahn

Publications and source records attributed to K H Rahn.

At least 163 records · Page 9Linked to original sources
PubMed1986

Studies on the antihypertensive effect of single doses of the angiotensin converting enzyme inhibitor ramipril (HOE 498) in man.

The time course of the blood pressure lowering effect and the dose-response relationship of the new angiotensin converting enzyme inhibitor ramipril (HOE 498) were studied in 8 patients, with essential hypertension. As compared with placebo, a single oral dose of 2.5 mg ramipril lowered systolic and diastolic blood pressure. The antihypertensive action of single oral doses of 5, 7.5 and 10 mg ramipril was more pronounced. No change in heart rate occurred. Angiotensin converting enzyme activity was suppressed after all doses of ramipril studied. Plasma renin activity increased after 2.5 mg and 5 mg ramipril. Plasma aldosterone was not affected by 2.5 mg, but it fell after 5 mg ramipril. Thus, ramipril produced prolonged inhibition (more than 12 hours) of angiotensin converting enzyme activity and lowered blood pressure in patients with essential hypertension.

Adult↗
PubMed1986

Influence of physical exercise on the pharmacokinetics of propranolol.

The pharmacokinetics of propranolol after oral and intravenous administration was studied at rest and on an exercise day in 8 healthy subjects. On the exercise day the subjects performed physical exercise for 7 h, consisting of bicycle ergometer exercise at 50% of maximal work capacity and outdoor walking. Propranolol (80 mg p.o., or 0.2 mg/kg body weight i.v.) was administered 30 min before the start of the exercise. After oral administration the terminal phase halflife, (t1/2 beta) and area under the curve (AUC) were both significantly reduced on the exercise day compared to the rest day. The bioavailability of propranolol was reduced by prolonged physical exercise and plasma levels of propranolol were about 30% lower at the end of the exercise day than at the end of the rest day. After intravenous administration, t1/2 beta was also reduced on the exercise day as compared to the rest day. AUC, clearance and volume of distribution did not differ on the two days. On the other hand, indocyanine green (ICG) clearance was significantly reduced during the bicycle ergometry periods on the exercise day. The combination of reduced ICG clearance, suggesting a reduction in hepatic blood flow, and a decreased t1/2 beta and unchanged clearance of propranolol on the exercise day was unexpected.

Administration, Oral↗
PubMed1985

Pharmacokinetics of verapamil in patients with renal failure.

The pharmacokinetics of verapamil was studied in patients with end-stage chronic renal failure and in normal subjects after i.v. injection of 3 mg and a single oral dose of 80 mg. Plasma levels of verapamil and its active metabolite norverapamil were measured by HPLC. After i.v. injection, the terminal phase half-life and total plasma clearance of verapamil in both groups were similar. Haemodialysis did not change the time course of plasma verapamil levels after i.v. administration. After a single oral dose, the plasma levels of verapamil and norverapamil in both groups of subjects were similar. Subsequently, normal volunteers and patients with renal failure were treated for 5 days with oral verapamil 80 mg t.d.s. There was no difference between the 2 groups of subjects in the trough and peak levels of verapamil or of norverapamil. Intravenous and oral administration of the calcium channel blocking agent had similar effects on blood pressure, heart rate and the PR-interval in the electrocardiogram in both groups. The study demonstrated that the disposition of verapamil was similar in normal subjects and in patients with renal failure.

Administration, Oral↗
PubMed1985

Salivary flow in borderline hypertension.

Salivary flow was studied in normotensives and in subjects with hypertension. Salivary flow rate was lower in borderline hypertensives than in normotensives. Propranolol, phentolamine and noradrenaline had no influence on salivary flow. Atropine decreased this parameter. The stimulating effect of neostigmine on saliva production was more pronounced in normotensives than in borderline hypertensives. The data support the assumption that in subjects with borderline hypertension the parasympathetic influence on the salivary glands is reduced.

Adult↗
PubMed1984

Studies of salivary flow in borderline hypertension: effects of drugs acting on structures innervated by the autonomic nervous system.

Salivary flow and the influence of drugs on this were studied in subjects with borderline hypertension and in normotensive subjects. Saliva production at rest was lower in borderline hypertensive subjects than in normotensive subjects. Plasma catecholamine levels were similar in both groups of subjects studied. Intravenous injections of propranolol and phentolamine did not enhance saliva secretion in the borderline hypertensive group, whereas atropine caused the secretion to decrease in both groups. Intravenous infusions of neostigmine led to a dose-dependent increase of salivary flow. The dose-response curve for the stimulating effect of neostigmine on saliva production was shifted to the right in borderline hypertensive as compared with normotensive subjects. The results of the study support the assumption that in subjects with borderline hypertension parasympathetic influence on the salivary glands is reduced.

Adult↗
PubMed1983

Haemodynamic effects of the optical isomers of beta-receptor blocking agents.

All beta-adrenergic blocking agents possess an asymmetric carbon atom in the side chain. Therefore there are two optical isomers. Pharmacological studies have clearly shown that the beta-adrenergic blocking action is almost exclusively due to the levorotatory isomer. Both, the levorotatory and the dextrorotatory isomer of some beta receptor blocking agents possess membrane stabilizing activity. Studies in patients with hypertension and in patients with coronary artery disease revealed that the beneficial effect of adrenergic beta receptor blocking drugs in these disease states is due to their beta adrenergic activity and not to the membrane stabilizing action.

Blood Pressure↗
PubMed1983

Clinical pharmacology of diuretics.

Diuretics belong to the drugs most frequently used. Thiazide diuretics, loop diuretics and potassium sparing diuretics are the agents with practical significance. Many data concerning the pharmacokinetics of these drugs have been reported. Nevertheless, the metabolism of some diuretics is not yet fully elucidated. There are numerous pharmacodynamic drug interactions with diuretics which in general can be predicted from the spectrum of pharmacodynamic actions of the drugs involved.

Canrenoic Acid↗
PubMed1983

Studies on salivary flow in borderline hypertension.

Salivary flow and the influence of drugs on this variable were studied in subjects with borderline hypertension and in normotensive control subjects. Saliva production under resting conditions was 0.85 +/- 0.08 g/min in normotensive subjects and 0.51 +/- 0.04 g/min in borderline hypertensive subjects. In both groups of subjects studied, salivary secretion was decreased by atropine but propranolol and phentolamine had no effect. The stimulating effect of neostigmine on saliva production was more pronounced in normotensive than in borderline hypertensive subjects. Thus, in order to increase salivary flow by 1 g/min 28 +/- 0.9 micrograms/min neostigmine had to be infused intravenously in normotensives compared with 41 +/- 3.8 micrograms/min in borderline hypertensives. The results of the study suggest that subjects with borderline hypertension have a reduced parasympathetic drive to the salivary glands.

Adult↗
PubMed1982

Studies on the autonomic nervous system in borderline hypertension.

Parameters of the autonomic nervous system were studied in normotensive subjects (NT; standing blood pressure (BP) less than or equal to 125/85 mmHg) and in subjects with borderline hypertension (BHT; 140/90 less than or equal to standing BP less than 160/100 mmHg). No differences in plasma noradrenaline and adrenaline levels were found between NT and BHT subjects, neither at rest nor during exercise at 75% of maximum work capacity. The dose of noradrenaline required to increase systolic BP by 10 mmHg was significantly higher in NT than in BHT subjects (5.13 +/- 0.42 vs 3.50 +/- 0.57 microgram . min -1). No difference between NT and BHT subjects was found in the dose of isoprenaline required to increase heart rate by 20 beats . min -1 (1.21 +/- 0.12 vs 1.09 +/- 0.11 microgram . min -1), suggesting decreased parasympathetic activity in the former group. The enhanced pressor effect of noradrenaline, together with the decreased parasympathetic activity, could explain the elevated blood pressure and heart rate in subjects with borderline hypertension.

Adolescent↗
PubMed1982

Effects of acute and long-term beta-adrenoceptor blockade with propranolol on haemodynamics, plasma catecholamines and renin in essential hypertension.

The effect of an acute intravenous and repeated oral doses of propranolol on haemodynamics, plasma and urinary catecholamines and plasma renin activity was studied in patients with essential hypertension. Intravenous injection of propranolol 5 mg produced a fall in cardiac output but had no consistent effect on blood pressure. Treatment with oral propranolol for 24 weeks lowered cardiac output and blood pressure; total peripheral resistance did not differ from the pretreatment values. Neither acute intravenous nor chronic oral administration of the beta-blocker affected the resting plasma levels of noradrenaline and adrenaline. Long-term treatment with propranolol reduced urinary excretion of vanilmandelic acid without affecting urinary catecholamine excretion. Acute intravenous injection of propranolol decreased plasma renin activity less than did chronic oral treatment with the drug. The observed time course of plasma renin activity was compatible with the view that suppression of this enzyme contributed to the antihypertensive effect of propranolol.

Adult↗