Homatropine

Homatropine, Homatropimim, Oxytoluyl-tropeinum, an ester compound of tropine alcohol and mandelic (phenylglycolic) acid—an artificial alkaloid of the formula C₁₆H₂₁NO₃. First synthesized by Ladenburg in 1880; optically inactive; however, if prepared from right- or left-rotating tropine, the corresponding optically active form is obtained. Homatropine hydrobromide (ФУП)—a white crystalline powder, odorless, soluble in 6 parts of water, the solution has a neutral reaction, melts at t° 209-212°, partially decomposing. The general effect of H. on the organism is similar to atropine, but only significantly weaker and passes more quickly. Toxic doses of H. in humans cause dryness in the mouth and throat, dilation of the pupils, weakness, an unsteady gait, confusion of thought, a depressed mood, and a transient slowing of the heartbeat, probably occurring due to the direct action of this alkaloid on the heart muscles (Bertheau). Locally, H. is used in the form of hydrobromide salt in ophthalmic practice for pupil dilation; especially frequently—for diagnostic purposes, since vision is disturbed only slightly and temporarily; dilation of the pupils occurs after 15-20 minutes, reaches its greatest magnitude in ¹/₂-1-2 hours, and disappears after 6-8 hours and, in any case, not later than a day; suppression of accommodation at this time is barely noticeable and quickly passes. For pupil dilation, a 1% solution of homatropine hydrobromide is used. Side effects from H. are very rare and may manifest as some irritation of the conjunctiva or general phenomena characteristic of the toxic effect of homatropine. Orally, H. is rarely used; the highest single dose of homatropine hydrobromide is 0.001, and the daily dose is 0.003 (Ph. VII). The mechanism of action of homatropine in its therapeutic application and in toxic cases is determined primarily by the paralysis of the nerve endings of the parasympathetic system,