Anorectal pruritus after intravenous hydrocortisone sodium succinate and sodium phosphate.

A double-blind study demonstrated that single intravenous doses of 100, 200, or 400 mg of hydrocortisone sodium succinate and hydrocortisone sodium phosphate were similar in eosinophil suppression, elevation of glucose, white blood count differential shifts (polymorphonuclear cells, lymphocytes, and monocytes), and urinary excretion of sodium and potassium but not in incidence of side effects. More subjects receiving hydrocortisone sodium phosphate experienced systemic or localized adverse effects than those receiving hydrocortisone sodium succinate. The most common side effect was burning or itching in the anorectal area, which occurred in 16 of 18 subjects medicated with hydrocortisone sodium phosphate, in 1 subject of 6 treated with placebo (saline), and in none who received the sodium succinate. The effect is attributed to the phosphate steroid and appears to last as long as it takes to convert to cortisol.

The clinical pharmacology of methylprednisolone sodium phosphate. I. Intramuscular route of administration.

Intramuscularly administered methylprednisolone sodium phosphate (Medrol Stabisol) in single doses of 40, 80, or 160 mg (methylprednisolone equivalents) had a similar effect as the same doses of methylprednisolone sodium succinate (Solu-Medrol) with regard to eosinophil suppression, elevation of glucose, white blood count differential shifts (lympholytic effect), urinary excretion of sodium and potassium, and localized (pain) and systemic side effects. The average plasma methylprednisolone concentration was approximately 20% higher after the intramuscular administration of methylprednisolone sodium phosphate than after methylprednisolone sodium succinate. The differences in plasma methylprednisolone levels produced by the two esters suggest that either hydrolysis of the succinate ester occurs more slowly or the succinate ester distributes more extensively. This difference in plasma level, however, is not reflected in any other pharmacologic evaluation of the two esters, e.g., both eosinophil depression and hyperglycemic response were identical. No clinically significant changes in the vital signs, standard hematology, and clinical chemistry parameters evaluated were noted after 21 successive doses (q.i.d. for five days with one dose in the morning of day 6) of 80 mg methylprednisolone sodium phosphate. An increase was noted in the systolic blood pressure from a pretreatment mean of 113 mm Hg to a posttreatment mean of 123 mm Hg and an increase in the body weight from a pretreatment mean of 177 pounds to a posttreatment mean of 183 pounds. No signs of adrenal suppression were found as judged by plasma cortisol and ACTH levels. Six (6/12) subjects of the methylprednisolone sodium phosphate group, one (1/12) subject of the vehicle group, and one (1/12) subject of the placebo (sterile saline) group reported the following systemic side effects: gas in stomach, headaches, anorectal itching, and dryness of itching of the skin. No trend was observed for any side effect reported. In these double-blind, randomized studies, single (40, 80, and 160 mg) and multiple (80 mg) intramuscular doses of methylprednisolone sodium phosphate were tolerated in healthy volunteers as well as the same doses of methylprednisolone sodium succinate and similar volumes of vehicle or placebo.

Pharmacokinetic interpretation of plasma cortisol and cortisone concentrations following a signle oral administration of cortisone acetate to human subjects.

The pharmacokinetic and biopharmaceutic profiles of a single dose of oral cortisone acetate were developed for 23 healthy normal adult volunteers using cortisone and cortisol plasma concentration data. Cortisone acetate was rapidly absorbed and converted to the therapeutic moiety cortisol. There was a linear increase in plasma concentrations and, therefore, areas under plasma concentration-time curves with increasing doses of 5, 10, and 25 mg. Twenty-five-mg doses given as 1 x 25 mg or 5 x 5 mg were found to be bioequivalent. The increased efficacy of oral over intramuscular cortisone acetate can be attributed to the increased conversion to cortisol as a result of first-pass metabolism following oral dosing.

Corticosteroids and bioavailability.

This presentation has attempted to provide a brief view of the importance of bioavailability and bioequivalence to those physicians who use corticosteroids. In particular it emphasizes that in vitro tests may not be reliable for predicting variability between formulations and, more importantly, cannot take the place of a bioavailability study. The implication would seen clear: namely, that a manufacturer who wishes to market a formulation similar to that already available and found to be acceptable clinically cannot rely on merely matching the standard formulation with in vitro tests but should substantiate that his formulation is, indeed, bioequivalent to the standard. In addition, data have been presented that clearly suggest the importance of bioavailability methodology as a new and useful pharmacological tool. In conclusion, as far as the bioavailability of corticosteroids in the marketplace is concerned, an old adage may be paraphrased: "If you don't know your bioavailability, know your manufacturer."

In vitro effect of methylprednisolone on protein synthesis of activated canine thymus-derived lymphocytes.

Technics of studying the protein synthesis of canine thymus-derived lymphocytes in vitro have been developed. Activation of these cells by PHA or MLC increases protein synthesis. Methylprednisolone decreases the stimulation of protein synthesis of these activated lymphocytes. The decrease in protein synthesis is not caused by lympholysis. In this respect, the dog, like man, can be considered a steroid-resistant animal. It is postulated that this effect of methylprednisolone contributes to its immunosuppressive action by inhibiting the afferent limb of the immune response.