What class of indirect cholinergic agonists is used clinically?

Reversible cholinesterase inhibitors represent a significant class of indirect cholinergic agonists that are used clinically. These agents work by temporarily inhibiting the enzyme acetylcholinesterase, which breaks down the neurotransmitter acetylcholine in the synaptic cleft. By preventing this degradation, reversible cholinesterase inhibitors increase the availability of acetylcholine at the neuromuscular junction and within the central nervous system, enhancing cholinergic transmission. This mechanism makes them particularly effective in treating conditions such as myasthenia gravis, a neuromuscular disorder characterized by weakness and fatigability of skeletal muscles.

Their effects are dose-dependent and can be reversed once the inhibitor is cleared from the body, allowing for a more controlled therapeutic approach. In contrast, irreversible cholinesterase inhibitors lead to permanent enzyme inactivation and are typically not used in clinical settings due to their toxicity and potential noxious side effects. Muscarinic blockers and skeletal muscle relaxants do not function as indirect cholinergic agonists; rather, they either block cholinergic activity or suppress muscular activity through other mechanisms.