Avertin (tribromethanol) was first introduced for clinical use as a crystalline preparation to be administered rectally as a 2.5 to 3 per cent solution in distilled water. The low solubility of the preparation in water (3.5 per cent at 40 C.) necessitates the rectal administration of relatively large volumes of fluid. At temperatures above 40 C. solutions of avertin decompose into hydrobromic acid and dibromacetaldehyde. Owing to these disadvantages, avertin fluid has largely displaced the aqueous solutions for clinical uses.
Avertin fluid contains in each cubic centimeter 1 Gm. of avertin crystals and 0.5 cc. (407.5 mg.) of tertiary amyl alcohol (amylene hydrate). This preparation is said to be more stable than the aqueous solutions of avertin, and the amylene hydrate has been reported to accelerate the rate of absorption of the solute from the rectum. In addition, since the solvent alone is somewhat hypnotic, the combination of avertin and