Medicinal Chemistry I

Edrophonium Chloride is a short-acting, quaternary ammonium compound classified as a reversible acetylcholinesterase inhibitor. It temporarily increases acetylcholine levels at neuromuscular junctions by inhibiting the enzyme acetylcholinesterase. Chemical Formula: C₁₀H₁₆ClNO Mechanism of Action: Short-acting reversible AChE inhibitor. Binds via electrostatic + hydrogen bonding, not covalent. Uses of Edrophonium Chloride: Diagnosis of myasthenia gravis (Tensilon test) … Read more

Pyridostigmine is a quaternary ammonium compound, and a reversible acetylcholinesterase inhibitor used to enhance cholinergic transmission by preventing the breakdown of acetylcholine at neuromuscular junctions. It is primarily indicated for the symptomatic treatment of myasthenia gravis, reversal of non-depolarizing neuromuscular blockade, and as a prophylactic agent against nerve gas poisoning. Chemical Formula: C₉H₁₃N₂O₂ Mechanism of … Read more

Neostigmine is a synthetic quaternary ammonium compound that acts as a reversible cholinesterase inhibitor. It inhibits the enzyme acetylcholinesterase, thereby increasing the concentration of acetylcholine at neuromuscular junctions and cholinergic synapses. Chemical Formula: C₁₂H₁₉N₂O₂⁺ Mechanism of Action: Reversible AChE inhibitor. Also has some direct nicotinic agonist activity at NMJ. Uses of Neostigmine: Myasthenia gravis Reversal … Read more

Physostigmine is a naturally occurring reversible cholinesterase inhibitor derived from the seeds of Physostigma venenosum (Calabar bean). It inhibits acetylcholinesterase, leading to increased levels of acetylcholine at synaptic and neuromuscular junctions. Chemical Formula: C₁₅H₂₁N₃O₂ Mechanism of Action: Reversible AChE inhibitor. Crosses blood-brain barrier (BBB) → CNS effects. Uses of Physostigmine: Antidote for anticholinergic toxicity (e.g. … Read more

Pilocarpine is a naturally occurring alkaloid and cholinergic parasympathomimetic agent that acts primarily as a muscarinic receptor agonist. It mimics the action of acetylcholine on muscarinic receptors, especially M3 receptors, stimulating smooth muscle contraction, glandular secretion, and pupil constriction. Chemical Formula: C₁₁H₁₆N₂O₂ Mechanism of Action: Muscarinic agonist, especially M3 Stimulates secretions and ciliary muscle contraction … Read more

Methacholine is a synthetic choline ester, and a non-selective muscarinic receptor agonist used primarily for diagnostic purposes. It mimics the action of acetylcholine on muscarinic receptors, particularly in the lungs and smooth muscles. Chemical Formula: C₈H₁₈ClNO₂   Mechanism of Action: Selective muscarinic agonist Slightly longer acting than ACh due to beta-methyl resistance to AChE. Uses … Read more

Bethanechol is a synthetic choline ester and a direct-acting parasympathomimetic agent that selectively stimulates muscarinic receptors (especially M3) in the gastrointestinal (GI) tract and urinary bladder. It mimics the effect of acetylcholine on smooth muscle without significant effects on nicotinic receptors or the central nervous system. Chemical Formula: C₇H₁₇NO₂ Mechanism of Action: Selective muscarinic agonist … Read more

Carbachol (Carbamoylcholine) is a cholinergic agonist that mimics the action of acetylcholine by stimulating both muscarinic and nicotinic receptors. Chemical Formula: C₆H₁₅ClN₂O₂ Mechanism of Action: Direct agonist at muscarinic and nicotinic Longer duration due to resistance to AChE. Uses of Carbachol: Used topically in glaucoma to reduce intraocular pressure. Also used to induce miosis during … Read more

Acetylcholine (ACh) is a neurotransmitter a chemical messenger that plays a key role in both the central nervous system (CNS) and peripheral nervous system (PNS). It is involved in transmitting nerve impulses across synapses, particularly at neuromuscular junctions, autonomic ganglia, and within the brain. Chemical Formula: C₇H₁₆NO₂⁺ Mechanism of Action: Mimics acetylcholine at muscarinic and … Read more

Classification of Parasympathomimetic Agents, also known as cholinergic agonists, are drugs that mimic the action of the parasympathetic nervous system (PNS) by stimulating cholinergic receptors (muscarinic and/or nicotinic). Classification of Parasympathomimetic Agents covers AChE inhibitors like Neostigmine, Physostigmine. A. Direct-Acting Parasympathomimetic Agents These agents bind directly to cholinergic receptors, mimicking the effect of acetylcholine. Mechanism … Read more