The Treatment of Human Pulmonary Tuberculosis With Cycloserine: Progress Report

¹ Department of Medicine, New York Medical College, and the Tuberculosis Division, Metropolitan Hospital, New York, New York.

Cycloserine, a new antibiotic, has been used in the treatment of 57 cases of pulmonary tuberculosis. These include the 37 original cases previously reported¹ and 20 additional subjects. Twenty-five were acute cases, previously untreated; 32 were chronic cases, therapeutically resistant to prior antimicrobial therapy.

Cycloserine was administered orally in a dose of 20 to 25 mg./Kg. of body weight per day (1.0 and 1.5 Gm.), in divided doses.

The incidence of side reactions was low. On the basis of neurological symptoms, both excitatory and depressant, it was necessary to discontinue therapy on five patients. Skin rashes of short duration and unknown cause occurred in three, in all of whom cycloserine was continued without further difficulty.

Although this study has run for a comparatively short time (five to 40 weeks), the following conclusions may be drawn from the data at hand:

1. Cycloserine has been found to be an efficient antibiotic agent in the treatment of acute, previously untreated cases of pulmonary tuberculosis. Sputum conversion, x-ray film clearing, gain in weight, and reduction of fever occurred promptly.

2. It fills the need for an antimicrobial agent in those cases of chronic tuberculosis which have failed to respond to existing drugs, especially patients who are inoperable because of extent of disease or poor condition.

3. In the daily dose of 20 to 25 mg./Kg. of body weight, over periods of up to 10 months of continuous therapy, cycloserine elicited few reactions other than those on psychotics and epileptics. The milder untoward symptoms disappear upon continued therapy.

4. Resistance to cycloserine by the tubercle bacillus has not developed either clinically or in in vitro studies. This is in contrast to presently available antitubercular drugs.

5. Studies are being carried out to determine the therapeutic compatibility between cycloserine and streptomycin, or INH. There may result a mixture between these which will prevent resistance and diminish or abolish toxicity.