Acting Cholinergic Stimulants

Direct-acting stimulants bind directly to the cholinergic receptor to activate it, which in turn initiates a cellular response. These stimulants may be considered 

FIGURE 19-1 T Mechanism of action of cholinergic stimulants. Direct-acting stimulants bind directly to the postsynaptic cholinergic receptor. Indirect-acting stimulants inhibit the cholinesterase enzyme, thus allowing acetylcholine to remain in the synaptic cleft. 

Indirect-acting stimulants increase activity at cholinergic synapses by inhibiting the acetylcholinesterase enzyme.21 This enzyme is normally responsible for destroying acetylcholine after this neurotransmitter 

Generic Name Trade Name(s) Primary Clinical Usefs)  

Bethanechol Duvoid, Urabeth, Urecholine Postoperative gastrointestinal and urinary atony 

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Unlike the systemic direct-acting cholinergic stimulants (e.g., bethanechol), cholinesterase inhibitors display a relative lack of specificity regarding which cholinergic synapses they stimulate. These drugs tend to inhibit the acetylcholinesterase found at... 

Increased stimulation of the AChR can be achieved in two ways (1) by binding of the directly acting cholinergic agonists to the AChR, triggering nicotinic or muscarinic... 

C. Metrifonate Metrifonate is an organophosphate prodrug that is converted in the body to the cholinesterase inhibitor dichlorvos. The active metabolite acts solely against Schistosoma haematobium (the cause of bilharziasis). Toxic effects occur from excess cholinergic stimulation. 

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