Prolonged Blood Levels with Sustained Action PAS

¹ The Chest Section, Medical Service, Veterans Administration Hospital.

1. Sustained action PAS tablets (Parasal-S.A., 1.0 Gm., sodium free) offer a convenient means of PAS therapy with a high degree of toleration. Acceptance of this drug was excellent since a four gram dose of free PAS consisted of only four tablets. Patients who manifested symptoms of gastrointestinal irritation due to standard PAS preparations tolerated sustained action PAS tablets with minimal, if any, gastrointestinal side-effects.

2. Sustained action PAS tablets, in dosage of four grams (4 tablets) three times daily at six hour intervals, generally provided sustained therapeutically effective PAS blood concentrations for 24 hours. No other PAS preparation, in equivalent dosage, studied to date, produced such sustained 24 hour PAS blood levels.

3. The clinical implications and probable advantages inherent in the use of sustained action PAS, administered concurrently with isoniazid or streptomycin, are believed to be as follows: a) sustained PAS concentrations within the tuberculous lesions; b) sustained and increased biologically active isoniazid levels in the blood and diseased tissues; c) greater inhibition or delay in the emergence of isoniazid or streptomycin resistant bacilli. Sustained action PAS may, therefore, serve to potentiate the therapeutic efficacy of antituberculous combined chemotherapy regimens.