Cholinergic Blocking Agents (Cholinolytics / Anticholinergics)

Cholinergic Blocking Agents

Definition of Cholinergic Blocking Agents (Cholinolytics / Anticholinergics) Cholinergic Blocking Agents (Cholinolytics / Anticholinergics) are compounds that inhibit the actions of acetylcholine (ACh) at muscarinic receptors (primarily), and in some cases, nicotinic receptors. They are also known as antimuscarinic agents or muscarinic antagonists. They block parasympathetic nerve impulses, leading to sympathomimetic effects, such as decreased … Read more

Pralidoxime Chloride (2-PAM)

Pralidoxime Chloride (2-PAM)

Pralidoxime Chloride (2-PAM): Antidote for organophosphate poisoning, reactivates acetylcholinesterase. Pralidoxime Chloride (2-PAM): Restores normal neuromuscular function, used in emergency toxicology. Chemical Formula: C₇H₉ClN₂O Mechanism of Action: Reactivates phosphorylated AChE by removing the phosphate group (only effective before “aging” of the bond). Must be given early in organophosphate poisoning. Uses of Pralidoxime Chloride (2-PAM): Antidote for … Read more

Malathion

Malathion

Malathion is an organophosphate insecticide widely used to control pests in agriculture and public health. Malathion treats head lice, mosquito control, and protects crops, ensuring safety with proper dosage and handling. Chemical Formula: C₁₀H₁₉O₆PS₂ Mechanism of Action: Irreversible AChE inhibitor after conversion to malaoxon Uses of Malathion: Head lice treatment Scabies Agricultural pesticide Side Effects … Read more

Parathion

Parathion is a highly toxic organophosphate pesticide used for pest control in crops. Parathion exposure can cause severe poisoning, affecting the nervous system. Chemical Formula: C₁₀H₁₄NO₅PS Mechanism of Action: Irreversible AChE inhibitor after bioactivation to paraoxon Uses: Agricultural insecticide (not for therapeutic use) Side Effects (Toxicity): SLUDGE syndrome: Salivation, Lacrimation, Urination, Diarrhea, GI upset, Emesis … Read more

Echothiophate Iodide

Echothiophate Iodide

Echothiophate Iodide Uses – Long-acting cholinesterase inhibitor for glaucoma, reducing intraocular pressure effectively. Echothiophate Iodide Action – Irreversibly inhibits cholinesterase, enhancing acetylcholine activity and improving ocular fluid outflow. Chemical Formula: C₉H₂₃I₂NO₄PS Mechanism of Action: Irreversible AChE inhibitor Long-acting due to covalent binding Uses: Chronic glaucoma Accommodative esotropia Side Effects: Miosis Brow ache Risk of cataracts … Read more

Isofluorphate (DFP – Diisopropyl fluorophosphate)

Isofluorphate (DFP – Diisopropyl fluorophosphate

Isofluorphate (DFP – Diisopropyl fluorophosphate) Agents: Potent irreversible cholinesterase inhibitors used in glaucoma. Isofluorphate (DFP – Diisopropyl fluorophosphate) Agents: Organophosphate derivative with strong parasympathomimetic action. Chemical Formula: C₃H₈FO₄PS Mechanism of Action: Irreversible AChE inhibitor. Covalently binds AChE → long-lasting cholinergic effects. Uses: Previously used for glaucoma (rare today). Side Effects: Cholinergic crisis (if overdosed) Muscle … Read more

Drug-Receptor Interactions

Drug-Receptor Interactions

Drug-receptor interactions describe how drugs bind to receptors, influencing potency, efficacy, and selectivity. Drugs produce their effects mainly by interacting with receptors—specific macromolecules usually found on or within cells. Key Concepts of Drug-Receptor Interactions: Receptor: A protein molecule that receives chemical signals from outside a cell. Ligand: A molecule (e.g., drug) that binds to a … Read more

Signal Transduction Mechanisms

Signal Transduction Mechanisms

This article explains about the Signal transduction mechanisms explain how receptors convert external signals into cellular responses. Signal Transduction Mechanisms Signal transduction is the process by which a chemical signal (like a drug or hormone) is transmitted from the outside of the cell to the inside, leading to a cellular response. Most drugs act through … Read more

G-Protein–Coupled Receptors (GPCRs)

G-Protein–Coupled Receptors (GPCRs)

GPCRs are membrane receptors that transmit signals via G-proteins, regulating many physiological processes. Structure of GPCRs: Single polypeptide chain with 7 transmembrane α-helices Coupled to G-proteins (GTP-binding proteins) inside the cell Mechanism of GPCRs: Agonist binds to receptor (outside of cell) Receptor undergoes conformational change Activates G-protein by exchanging GDP for GTP G-protein dissociates into … Read more

Ion Channel-Linked Receptors (Ligand-Gated Ion Channels)

Ion Channel-Linked Receptors (Ligand-Gated Ion Channels)

This article explains about the Ligand-gated ion channels are receptors that open or close ion pathways in response to specific ligands. Structure of Ligand-gated ion channels: Multi-subunit protein with a central ion pore Opens or closes in response to ligand (drug/neurotransmitter) binding Mechanism: Ligand binds to receptor Ion channel opens Specific ions (Na⁺, K⁺, Ca²⁺, … Read more