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In eight healthy volunteers pretreatment with phentolamine 40 mg p o inhibited platelet aggregation (1st and 2nd phases) induced by low concentrations of adrenaline (2, 1 and 0.5 µM) in plasma from blood sampled 30 min after administration of the compound. The lower the concentration of adrenaline used, the greater was the degree of inhibition elicited. These results are indicative of competitive inhibition of the action of adrenaline on the platelet membrane by phentolamine. Four to six hours after administration of the compound, the aggregation characteristics had reverted to normal. It is concluded that the increased tendency toward platelet aggregation associated with elevated blood levels of catecholamines can be prevented by therapeutic doses of phentolamine.

Twenty-six Swiss physicians took part in a study in which the effects of an orally administered new beta-receptor blocking agent, Trasicor®, were assessed in out-patients with disturbances of cardiac rhythm. Ninety-eight patients were treated for 3 weeks with daily doses ranging from 20 to 120 mg, the most commonly employed daily dose being 60 mg. The patients were examined before treatment and again after 1, 3, 7, 14 and 21 days of treatment. The compound proved highly effective in decreasing heart rate in sinus tachycardia and ventricular rate in chronic auricular fibrillation, both at rest and during effort. Trasicor also abolished, or substantially reduced, the frequency of attacks of paroxysmal supraventricular tachycardia and ventricular ectopic beats. — In hypertensive patients, Trasicor elicited a statistically significant decrease in both the systolic and diastolic blood pressures, whereas in normotensives only the systolic blood pressure was affected to a statistically significant extent. - Side effects were usually mild and transient; treatment had to be withdrawn in only a small percentage of patients.

Investigations in six healthy volunteers given single oral doses of sulphinpyrazone (Anturan®) showed that the drug had a potent uricosuric effect, even if the concentration of uric acid in the plasma was normal. In the dose range tested of 50 to 800 mg the increase in uric acid excretion was dose-related. It reached a maximum within 2 h and was still detectable 6–8 h after the drug was taken. There was a corresponding dose-related reduction in the plasma concentration of uric acid, which reached its lowest level after 8–10 h. The administration of 300 mg twice daily for four days to a further five healthy volunteers reduced plasma uric acid from 5.06 to 1.8 mg%. The findings indicate that, even if plasma uric acid levels are unknown, it would be advisable to avoid the risk of formation of urinary calculi by administering sulphinpyrazone in gradually increasing doses, ensuring adequate fluid intake and alkalinizing the urine during the first few days of treatment.