Para-aminosalicylic-acid (PAS) concentrations in the serum during treatment with various PAS preparations

Serum PAS concentrations during treatment with sodium PAS in solution and cachets have been compared with those obtained during treatment with other preparations of PAS. Preparations of sodium PAS in the form of granules and effervescent tablets and calcium PAS cachets gave serum levels similar to those after sodium PAS cachets. An enteric coated tablet of sodium PAS gave low levels. Phenyl PAS gave low but steady levels. Calcium benzoyl PAS gave very low levels and a review of the available information about this drug leads the authors to conclude that it cannot be recommended as an alternative to conventional PAS preparations. The advantages and disadvantages of the various forms of PAS preparations are discussed.