Cholinerge antagonisten: farmacokinetiek

Cholinergic antagonists—such as antimuscarinics—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,  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.