Homatropine bradycardia in man

Abstract

New York, N. Y. Department of Pharmacology and Division of Cardiology, Department of Medicine, Cornell University Medical CollegeSlowing of human sinus heart rate by small doses of atropine has been known for many years. 5 McGuigan 16 in 1921 and many others 18 -21 found that in most cases subcutaneous administration of 0.5 mg. produced slowing; this effect has also been reported after intramuscular,21 intravenous 1 , 3, 4,8,13,15,18,19,21 558heart rate, or interaction with concurrent drug medication. Above all the dose-response relations for cardiac slowing by these agents have not been examined.We chose to use homatropine, the mandelic acid congener of atropine, for three reasons. In studies on rat behavior, Machp7 showed that homatropine has relatively more stimulating and less depressant properties on the central nervous system than atropine. Homatropine is a considerably less potent anticholinergic than atropine. 7 Thus slowing produced by homatropine might be less likely to be antagonized by vagolytic action. Definition of a slowing action for homatropine would extend our knowledge of this class of drugs. Materials and methodsThe study was conducted in two groups of subjects: the first, 8 healthy, male medical students between 21 and 24 years old;

Characterizing the subjective, psychomotor, and physiological effects of a hydrocodone combination product (Hycodan) in non-drug-abusing volunteers

“…In fact, heart rate effects were the only effects noted in this study with the lowest dose of HC/HO tested. A closely related compound, homatropine hydrobromide, at low doses, induced bradycardia, and at higher doses induced tachycardia (Hayes and Katz 1970), a phenomenon also noted with atropine (Morton and Thomas 1958). Thus it appears that the subtherapeutic-to-therapeutic doses of homatropine used in the present study may have been inducing two peripheral effects, slowing gastric motility and heart rate.…”