BIOASSAY OF THE DIURETIC POTENCY OF XANTHINES AND THE ORGANIC MERCURIALS IN PATIENTS WITH CONGESTIVE FAILURE

¹ Department of Pharmacology of Cornell University Medical College, the Cardiovascular Research Unit of the Beth Israel Hospital, and the Cardiology Service of the Hospital for Joint Diseases, New York City

The diuretic activity of theophylline in the form of aminophylline and calcium theophyllinate was assayed against Mercuhydrin in ambulant patients with congestive failure.

A large intramuscular dose, 0.5 gm., aminophylline, causes a diuretic effect equal to that of 0.6 ml. Mercuhydrin by intramuscular injection. Aminophylline is somewhat less effective by the oral route.

In terms of molecular weight, aminophylline and calcium theophyllinate have equal diuretic potency. This raises a question concerning the difference in absorption of the two materials, since one contains twice as much theophylline as the other.

Aminophylline may enhance the diuretic activity of the organic mercurials by approximately 50 per cent. In contrast to the case of ammonium chloride, the result does not represent potentiation, but simple summation or less than summation.

While there is ample evidence that aminophylline can boost the diuretic response with suboptimal dosage plans of the mercurials, the proof is not sufficient for the assumption that the xanthines will restore diuretic response in patients refractory to the organic mercurials.