Indomethacin and sulindac were used as tools to study the role of renal and/or systemic prostaglandins in the pharmacological response to atenolol. Patients receiving chronic treatment with atenolol 100 mg received indomethacin 50 mg twice daily or sulindac 200 mg twice daily in a randomised crossover trial. Indomethacin significantly reduced the antihypertensive action of atenolol while sulindac had no effect. The role that systemic and/or renal prostaglandins may play in the antihypertensive action of atenolol is discussed with reference to renal PGI production and inhibition of platelet cyclo-oxygenase.

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Aspirin at low doses is used as an inhibitor of platelet aggregation and is frequently administered to essential hypertensive patients with arterial thrombotic complications. However, it is unknown whether aspirin can modify blood pressure values either in treated or untreated hypertensive patients, as described for other non steroidal anti-inflammatory drugs. Thus 30 patients. 10 with mild uncomplicated and untreated essential hypertension, 10 with essential hypertension under chronic treatment with captopril, 50 mg bid, and 10 with essential hypertension under chronic treatment with atenolol, 100 mg oid, received aspirin, 100 mg oid, and the corresponding placebo for one month, according to a double blind randomized cross-over design. At the end of each treatment, blood pressure, heart rate, generated serum thromboxane B2 and urinary excretion of thromboxane B2 and 6 keto prostaglandin F1 alpha and plasma renin activity were measured. Both in treated and untreated essential hypertensive patients, aspirin administration did not affect blood pressure, heart rate and urinary 6 keto prostaglandin F1 alpha, while it significantly reduced serum and urinary excretion of thromboxane B2 and plasma renin activity. In conclusion, while the present data confirm that low doses of aspirin selectively inhibit thromboxane B2 synthesis, they indicate that aspirin at 100 mg oid can be administered to treated and untreated essential hypertensive patients without any harmful effect on blood pressure values.

To evaluate whether, in the forearm of hypertensive patients with different circulating renin profiles, local beta-adrenergic receptor-induced production of active renin, plasma renin activity, angiotensin I (Ang I), and angiotensin II (Ang II) was or was not related to the renin profile, we studied four groups of patients: 1) hypertensive patients with primary aldosteronism and suppressed circulating plasma renin activity values (0.15 +/- 0.1 ng Ang I/mL per hour; n = 7), 2) essential hypertensive patients with low (0.47 +/- 0.1 ng Ang I/mL per hour; n = 8) circulating plasma renin activity values, 3) essential hypertensive patients with normal (2.48 +/- 0.52 ng Ang I/mL per hour; n = 8) circulating plasma renin activity value, and 4) renovascular hypertensive patients with high circulating plasma renin activity values (4.16 +/- 2.1 ng Ang I/mL per hour; n = 10). Isoproterenol was infused into the brachial artery, and active renin, plasma renin activity, and Ang I and Ang II forearm balance (venous-arterial differences corrected for forearm blood flow by strain-gauge plethysmography) were measured. Despite a comparable vasodilation, beta-adrenergic stimulation failed to release active renin, plasma renin activity, and Ang I and Ang II in primary aldosteronism. It slightly increased them (except for Ang I) in low renin patients but determined a local production in normal renin and renovascular hypertensive patients. The individual increments in plasma renin activity and Ang II release induced by isoproterenol showed a correlation with the renin profile.(ABSTRACT TRUNCATED AT 250 WORDS)

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