Adrenocorticotrophic Effect of Intravenous PAS and Its Therapeutic Implications

With a view to explain the therapeutic superiority of short intravenous perfusions of PAS over its oral form of administration in pulmonary tuberculosis, a comparative study of the ACTH-releasing effect of the two routes of administration was conducted in 12 young female tuberculous patients. They were successively treated with 15 gm. of sodium PAS administered orally in either one massive dose or three spaced portions, and with one-hour intravenous perfusions of the same amount, dissolved in 500 cc. of bidistilled water. The effect of PAS on the circulating blood eosinophils and lymphocytes, hypoglycemic response to insulin and inflammatory reaction to cantharidine, which were used as indices of pituitary-adrenal activation, proved directly related to the mode of administration of the drug. It was marked as a result of the perfusions and slight or absent following oral administration. It is concluded that the higher blood concentration of intravenously administered PAS acts as a stressing agent and induces the release of ACTH from the pituitary. The consequent antiinflammatory property of intravenous PAS perfusions is tentatively correlated with their therapeutic efficiency.