Toleration and Absorption of Sodium Para-Aminosalicylate and Para-Aminosalicylic Acid (Neopasalate)

Comparison with Other Forms of Para-Aminosalicylic Acid

¹ Medical Department, Glen Lake State Sanatorium

The toleration and absorption of p-aminosalicylic acid (PAS) were studied in a group of 709 tuberculosis patients who were given one of these six types of PAS: Neopasalate, resin complex PAS, phenyl PAS, or salts of calcium, potassium, or sodium PAS. Findings in the six groups were compared.

A total of 2,439 determinations of blood serum levels—1,046 in our previous investigations and 1,393 in the present study— were made, with test periods up to 24 hours after ingestion of morning doses of PAS. Roentgenographic and bacteriologic studies were made on those patients who were followed for three months or more.

Neopasalate appeared to be well tolerated as determined by toxicity findings in the 122 patients on that medication. Only 7.38 per cent exhibited moderate to severe gastrointestinal irritation or other toxicity symptoms as compared with the 20.84 per cent of the 168 patients who were on sodium PAS.

Both Neopasalate and sodium PAS were capable of producing high peak serum levels following administration of single large morning doses of PAS; both maintained high serum levels of more than one mg. per 100 ml. serum for more than 17 hours. The single daily morning doses of isoniazid and PAS proved to be effective, practical, and tolerated by patients in this study.

All patients with positive cultures who received Neopasalate in conjunction with isoniazid or streptomycin or both converted to negative cultures.