BACKGROUND Sumatriptan (GR43175) is a selective 5-hydroxytryptamine (5HT1) receptor agonist effective in the acute treatment of migraine. Recent in vitro experiments suggest that it has vasoactive properties in vascular beds distinct from the cerebral circulation. The object of this study was to assess the vasoactive effects of the standard 6-mg subcutaneous dose of sumatriptan used in migraine on the systemic and pulmonary circulations and the coronary artery vasculature. METHODS AND RESULTS Ten patients undergoing diagnostic coronary arteriography were studied with digital subtraction angiography and invasive hemodynamic monitoring. After subcutaneous injection of sumatriptan, there was no significant change in heart rate or ECG morphology. There was a significant rise in the systemic (20%, p < 0.05 by ANOVA) and pulmonary artery (40%, p < 0.05 by ANOVA) pressures. There was no change in cardiac output, but there was a significant increase in total systemic (27%, p < 0.05) and total pulmonary vascular resistance (40%, p < 0.05). Sumatriptan caused a significant reduction (p < 0.001 by ANOVA) in mean absolute coronary artery diameter, from 4.36 +/- 1.60 mm at baseline to 3.67 +/- 1.49 mm (16%) at 10 minutes and to 3.63 +/- 1.49 mm (17%) at 30 minutes after injection. There were no clinical sequelae. CONCLUSIONS Sumatriptan, a 5HT1 receptor agonist administered by the subcutaneous route, causes a vasopressor response in the systemic and pulmonary arterial circulations and coronary artery vasoconstriction.

The benefits of exercise in the prevention of cardiovascular disease are irrefutable. However, the optimum 'dose' of exercise in order to derive the maximum cardiovascular benefit is not certain. Current national and international guidelines advocate the benefits of moderate-intensity exercise. The relative benefits of vigorous versus moderate-intensity exercise have been studied in large epidemiological studies, addressing coronary heart disease and mortality, as well as smaller randomized clinical trials which assessed effects on cardiovascular risk factors. There is evidence that exercise intensity, rather than duration or frequency, is the most important variable in determining cardioprotection. Applying this evidence into practice must take into account the impact of baseline fitness, compliance and the independent risk associated with a sedentary lifestyle. This review aims to evaluate the role of exercise intensity in the reduction of cardiovascular risk, and answer the question: should you be advising your patients to walk or run?

Objective-To examine the efficacy, safety, and the pharmacokinetic profile of a bolus dose administration regimen of alteplase in the treatment of acute myocardial infarction.Design-An open pilot study. Setting Alteplase (recombinant tissue plasminogen activator) is successful in restoring coronary patency, 61 with higher patency rates than a conventional dose of intravenous streptokinase.67 At present, the recommended dosage regimen for alteplase is a 10 mg bolus, with a tapering dose of 90 mg infused over three hours. This regimen was based on the apparent short half life of alteplase in the circulation,'2 but clearly this regimen is a cumbersome one to apply urgently.We assessed the efficacy of two boluses of 35 mg alteplase administered intravenously 30 minutes apart in achieving angiographic coronary patency. We also studied the pharmacokinetics of this regimen.

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