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June 1968

Effect of Pilocarpine in Counteracting Mydriasis

Author Affiliations

Rochester, Minn
From the sections of biophysics (Dr. Ogle) and ophthalmology (Dr. Kearns), Mayo Clinic and Foundation, and the Mayo Graduate School of Medicine (Dr. Anastasi), Rochester.
Dr. Ogle died Feb 22, 1968.

Arch Ophthalmol. 1968;79(6):710-715. doi:10.1001/archopht.1968.03850040712009

The effectiveness of 1% pilocarpine in counteracting the mydriatic effect of phenylephrine hydrochloride (Neo-Synephrine Hydrochloride), hydroxyamphetamine hydrobromide (Paredrine), tropicamide (Mydriacyl), and homatropine hydrobromide in the concentrations ordinarily used in clinical ophthalmology was studied in 15 subjects. Pupillary diameters were measured with the infrared electronic pupillograph. It was found that the mydriatic effects of the sympathomimetic drugs (phenylephrine and hydroxyamphetamine) are rapidly counteracted by pilocarpine, usually in much less than 30 minutes. However, after mydriasis with parasympatholytic drugs (tropicamide and homatropine), pilocarpine produced little effective miosis and the pupil remained dilated or semidilated for a prolonged period.

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