Muscle relaxants 382 INDEX

Atropine is the classic anticholinergic bronchodila-tor. It antagonizes acetylcholine, resulting in reduced intracellular cyclic guanosine monophosphate (cGMP) and smooth muscle relaxation. In horses, the therapeutic index of atropine is narrow and the duration of action is short (0.5-2.0 h). Adverse systemic effects associated with parenteral atropine administration include mydriasis, ileus, dry mucous membranes, blurred vision, excitement and tachycardia. Atropine is not suitable for routine administration to horses with recurrent airway obstruction. 

This book may be used as an encyclopedia of medications in which componnds appear under their generic names in alphabetical order from Abacavir sulfate, to Zopiclone, the first componnd of the cyclopytolone class possessing anticonvulsant, anxiolytic, muscle relaxant, and sedative properties. Furthermore, in the index, all drugs, including their generic names and multiple trade names, appear in alphabetical order. 

Clomethiazole has sedative, muscle relaxant, and anticonvulsant properties. It is used outside the U. S. for hypnosis in elderly and institutionalized patients, for preanesthetic sedation, and especially in the management of withdrawal from ethanol. Given alone, its effects on respiration are slight, and the therapeutic index is high. However, deaths from adverse interactions with ethanol are relatively frequent. 

In 113 patients undergoing general anesthesia, intravenous midazolam 15 mg slowed recovery of the twitch height after vecuronium and atracurium compared with diazepam. The recovery index was not altered (162). However, in another study in 20 patients, midazolam 0.3 mg/kg did not affect the duration of blockade, recovery time, intensity of fasciculations, or adequacy of relaxation for tracheal intubation produced by suxamethonium 1 mg/kg, nor the duration of blockade and adequacy of relaxation for tracheal intubation produced by pancuronium 0.025 mg/kg in incremental doses until 99% depression of muscle-twitch tension was obtained (161). Furthermore, in 60 patients undergoing maintenance anesthesia randomly assigned to one of six regimens (etomidate, fentanyl, midazolam, propofol, thiopental plus nitrous oxide, or isoflurane plus nitrous oxide), midazolam did not alter rocuronium dosage requirements (165). 

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