Q: Do you have any info as to how to use spironolactonetopically?
A: Spironolactone, a steroid with a structure similar tothat of the endogenous adrenocorticoid aldosterone,occurs as a white or yellowish-white powder with a characteristicodor. It has a molecular weight of 416.6 and is practicallyinsoluble in water and soluble in ethanol. It should be protectedfrom light. Extemporaneously prepared oral suspensionshave been reported to be stable for 60 to 90 days. It is a competitiveantagonist of aldosterone in the distal portion of therenal tubule and is administered systemically as a potassium-sparingdiuretic.
Spironolactone has antiandrogenic properties and hasbeen studied as oral therapy for acne vulgaris where othermethods of treatment failed; the reports have been positive. Ithas been included in topical formulations for acne, as well asfor hirsutism. When used in this way, the results have beenvariable. Some research indicates that the vehicle for applicationand delivery may affect the response. One reported formulationemployed 5% spironolactone in a gel vehicle appliedfor 8 weeks and showed a reduction of sebum secretion ratesafter 12 weeks. Possible gel vehicles are methylcellulose (5%-8%) or Carbohol gel. The latter contains alcohol for improvedsolubility of the spironolactone. When compounding thepreparation, ensure that the drug is finely triturated to impalpabilitywith a ceramic or Wedgwood mortar and pestle;ensure homogeneity using geometric levigation techniqueand a levigating agent appropriate to the vehicle chosen.
One study suggested that chronic use of a topical formulationof spironolactone could affect blood pressure; the pharmacistmay wish to advise the patient and physician and/ormonitor the patient for this effect.
Mr. Erickson is director of professional affairs at Gallipot Inc.
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