Name: Cholinergic Antagonists: Pharmacokinetics
Uploaded: 2023-09-22T11:46:20
Description: Learn by watching this video about Cholinergic Antagonists: Pharmacokinetics at JoVE.com

Cholinergic antagonists&#8212;such as antimuscarinics&#8212;are administered either orally, as eye drops, as transdermal patches, as aerosols, or as injections.
Recall that the quaternary antimuscarinics are ionic, resulting in their low lipid solubility and restricted penetration to the BBB. Moreover, they are poorly absorbed from the gut, skin, or eye.
In contrast, tertiary derivatives have higher lipid solubility and are well-absorbed centrally as well as peripherally.
As these agents have a varied duration of action, they are classified as SAMA, and LAMA.
They are metabolized in the liver by hydrolysis or conjugation and are excreted via urine.
The effect of antimuscarinics is pronounced when co-administered with drugs having anticholinergic properties such as antihistamines, antipsychotics, or antidepressants,&#160; due to their additive side effects.
Lastly, antimuscarinics are known to partially suppress the peristaltic movement of the stomach, delaying gastric emptying and leading to slow absorption of co-administered drugs.

cholinergic antagonists: pharmacokinetics

Cholinergic antagonists&#8212;such as antimuscarinics&#8212;are available in oral, topical, ocular, parenteral, and inhalational formulations. Most antimuscarinics are oral formulations,&#160; while scopolamine is available as a topical patch, and ipratropium and tiotropium are available as inhalation aerosols or powders. Atropine, tropicamide, and cyclopentolate are topically instilled in the eye. Most antimuscarinics are lipid-soluble and readily absorbed from the gastrointestinal tract and the conjunctiva. However, when inhaled, quaternary antimuscarinics are less lipid soluble and have limited systemic absorption.
Antimuscarinics are distributed throughout the body, with tertiary antimuscarinics penetrating the blood-brain barrier, while quaternary compounds are excluded from the brain. Antimuscarinics undergo hepatic metabolism, and elimination with atropine rapidly metabolizing in the liver and excreted unchanged in the urine. Most swallowed ipratropium and tiotropium are excreted via feces. Elimination of quaternary compounds is generally slower.
Based on their duration of action, antimuscarinics are categorized as either short-acting antimuscarinics (e.g., ipratropium) or long-acting (e.g., glycopyrrolate, tiotropium, and aclidinium). Antimuscarinics also interact with other drug classes, including tricyclic antidepressants, antihistamines, antianxiety and antipsychotic agents, which can exacerbate antimuscarinic side effects. Antacids can increase the stomach pH and form complexes with antimuscarinics, reducing their absorption.&#160;

Learn by watching this video about Cholinergic Antagonists: Pharmacokinetics at JoVE.com

Cholinergic Antagonists: Pharmacokinetics

Cholinergic antagonists&#8212;such as antimuscarinics&#8212;are available in oral, topical, ocular, parenteral, and inhalational formulations. Most ...