Mebutamate (Capla) (300 mg.) was a depressor in hypertension in single patient tests in which meprobamate (400 mg.) was not. In 30 outpatients mebutamate alone (600-1,200 mg. per day) was effective in most with mild or moderate diastolic hypertension and, with thiazides, e.g., hydrochlorothiazide, in most with moderately severe and even severe hypertensive disease, including some with arteriosclerotic "mixed" hypertension. A subsequent "blind" study of 10 patients verified this impression. Alone, or in combination, mebutamate is usefully antihypertensive in what seems to be a majority of office patients with hypertension; some patients report a disturbing, usually transient, drowsiness when given full doses (300-mg. four times a day); initial dosage may be desirably 150 mg. three times a day and 300 mg. at bedtime. No serious side effects characteristic of Rauwolfia drugs and ascribable to mebutamate were observed during nearly 1 year in 34 patients. Mebutamate is ineffective in malignant hypertension.
Corcoran AC, Loyke HF. Mebutamate as Antihypertensive Agent in Hospital Outpatients. JAMA. 1962;181(12):1043-1049. doi:10.1001/jama.1962.03050380021006