Indomethacin Antagonises the Antihypertensive Effect of AtenololBut when given as short term treatment the interference is slight or moderate

In an open study, 12 men with essential hypertension (diastolic BP ;?; 110mm Hg) received placebo for 2weeks followed by indomethacin 75 mg/day for 1 week, atenolol 50mg bid for 3 weeks, indomethacin +atenolol for 1 week and placebo for 3 weeks.

Indomethacin alone slightly increased BP, significant only for standing systolic BP. Further, compared withplacebo, indomethacin decreased plasma renin activity and the urinary excretion of prostaglandin (PG) E2 , 6­keto-PGF1a and thromboxane B2 . The decrease in the excret ion of 6-keto-PGF1a correlated closely with theincrease in standing BP. Atenolol alone significantly decreased supine BP and plasma renin act ivity comparedwith placebo. When indomethacin was combined with atenolol, diastolic BP increased compared with supine(p < 0.05) and standing (p < 0.01) values for atenolol alone, but remained below the placebo values. Plasma

renin activity decreased slightly but this decrease was significantly greater than that for either drug alone. Nosignificant changes in urinary excretion of kallikrein, plasma kininogen levels, urine volume or glomerularfiltration rate were reported during the study. Both active drugs were well tolerated and the authorsconcluded that short term treatment with indomethacin interfered only'• • • slightly or moderately with theantihypertensive effect of atenolol in patients with moderate essential hypertension'.Ylilals, P ; Pitkajarvi, T ; Pyykonen, M.L ; Nurim, A.-K.; Seppala, E. et a/.; Clinical Pharmacology and Therapeutics 38: 443-449 (Oc t 1985)

o156-2703/85/100S.(J0 IS/0$0 1.00/0 e ADIS Press INPHARMA(') 30 Nov 1985 15