Ganglion blocking drugs are used rarely because more selective autonomic blocking agents are available. Mecamylamine blocks central nicotinic receptors and has been advocated as a possible adjunct with the transdermal nicotine patch to reduce nicotine craving in patients attempting to quit smoking. The toxicity of the ganglion-blocking drugs is limited to the autonomic effects already described. For most patients, these effects are intolerable except for acute use.
•DicyclomineCompetitive antagonism at M3 receptors Reduces smooth muscle and secretory activity of gut Irritable bowel syndrome, minor diarrhea •Hyoscyamine: Longer duration of action OPHTHALMOLOGY •AtropineCompetitive antagonism at all M receptors
URINARY •OxybutyninSlightly M3-selective muscarinic antagonist Reduces detrusor smooth muscle tone, spasms Urge incontinence; postoperative spasms
Darifenacin, solifenacin, and tolterodine: Tertiary amines with somewhat greater selectivity for M3 receptors
Trospium: Quaternary amine with less CNS effect
Homatropine: Shorter duration of action (12–24 h) than atropine
Cyclopentolate: Shorter duration of action (3–6 h)
Tropicamide: Shortest duration of action (15–60 min)
Retinal examination; prevention of synechiae after surgery
Available in oral and parenteral forms • short t½ but action lasts up to 6 hours • Toxicity:
Tachycardia, confusion, urinary retention, increased intraocular pressure • Interactions:
Used as drops • long (5–6 days) action • Toxicity:
Increased intraocular pressure in closed-angle glaucoma • Interactions: With other antimuscarinics • Tiotropium, aclidinium, and umeclidinium: Longer duration of action; used once daily
Oral, IV, patch formulations • Toxicity:
Tachycardia, constipation, increased intraocular pressure, xerostomia • Patch: Pruritus • Interactions: With other antimuscarinics
AChE, acetylcholinesterase; CNS, central nervous system; COPD, chronic obstructive pulmonary disease; IM, intramuscular.
Belladonna alkaloids, extract, Generic or tincture
Clidinium Generic, Quarzan, others
Cyclopentolate Generic, Cyclogyl, others
Darifenacin Generic, Enablex
Dicyclomine Generic, Bentyl, others
Flavoxate Generic, Urispas
Glycopyrrolate Generic, Robinul (systemic) Seebri Neohaler (oral inhalation)
Homatropine Generic, Isopto Homatropine, others l-Hyoscyamine Anaspaz, Cystospaz-M, Levsin, others
Ipratropium Generic, Atrovent
Methscopolamine Generic, Pamine
Oxybutynin Generic, Ditropan, Gelnique, others
Propantheline Generic, Pro-Banthine, others
Tolterodine Generic, Detrol
Tropicamide Generic, Mydriacyl Ophthalmic, others
Trospium Generic, Sanctura
CHOLINESTERASE REGENERATOR Pralidoxime Generic, Protopam *Antimuscarinic drugs used in parkinsonism are listed in Chapter 28.
Brodde OE et al: Presence, distribution and physiological function of adrenergic and muscarinic receptor subtypes in the human heart. Basic Res Cardiol 2001;96:528.
Cahill K et al: Pharmacological interventions for smoking cessation: An overview and network meta-analysis. Cochrane Database Syst Rev 2013;5:CD009329.