The Prevention of Tetany by the Oral Administration of Ammonium Chloride.

Previous experiments^1,2 carried out on parathyroidectomized dogs have demonstrated the effectiveness of the lactates of strontium and magnesium in relieving tetany and in bringing about a cure. Experiments carried out last spring show that ammonium chloride also is an effective agent.

Parathyroidectomized dogs given a 5 per cent solution of ammonium chloride in 100 cc. doses twice daily, 3 to 4 hours before, and 5 to 8 hours after feeding, will retain the solution and may be kept free from tetany for long periods. One dog, reported here, never showed any symptoms of tetany save for a slight depression 4 days after operation. Once tetany appears, and the serum calcium falls below 7 mgm. per 100 cc., the ammonium chloride brings about a recovery within 2 hours, usually 1 hour and 15 minutes after administration. Examinations of the serum calcium at this time shows that the calcium has risen, on the average 2 ½ mgm. or to 8.5 mgm. per 100 cc., which is above the level at which tetany appears in dogs.

The experiments indicate clearly that ammonium chloride exerts a marked influence on tetany, probably more through its acidotic effect on the organism, than through an immediate effect on the serum calcium, although the rise in serum calcium may be sufficient to cause the disappearance of tetany symptoms.

Six dogs were parathyroidectomized. Dogs 4 and 6 were allowed to develop tetany; they recovered in l 1/4 hours after receiving 100 cc. of 5 per cent solution NH₄Cl. The calcium of dog 6 rose from 6.6 mgm. to 10.1 mgm. per 100 cc. This was the greatest rise obtained for the 1 1/4-hour period,