ATC Code A07DA03
Formula C29H33ClN2O2
Molar Mass (g·mol−1) 477,04
Physical State solid
Melting Point (°C) 222–223
PKS Value 8,6
CAS Number 53179-11-6
PUB Number 3955
Drugbank ID DB00836
Solubility soluble in water


Loperamide is a so-called peristaltic inhibitor. It is used for the symptomatic treatment of diarrhoea. It is the most widely sold active ingredient of this type and is also included on the WHO's list of essential medicines.

Loperamide does not require a prescription and is usually taken in the form of a tablet.



Loperamide has structural properties of an opioid and therefore binds to certain opioid receptors in the nerves of the intestine. This reduces the activity of the small intestinal muscles and the intestinal contents take longer to pass through. This gives more time for the intestinal contents to extract water. Loperamide, unlike conventional opioids, has no effect on the central nervous system.


Plasma protein binding is 97% and plasma half-life is 9-14 hours. Loperamide is metabolized mainly in the liver and subsequently excreted almost entirely in the stool.

Drug interactions

When taken with quinidine, verapamil or ketoconazole, respiratory depression may occur.


Signs of overdose include dizziness, nausea, fatigue, and constipation.

Side effects

Common side effects include constipation, nausea, dizziness, headache, and flatulence.

Toxicological Data

Oral, mouse: LD50 = 105 mg/kg.

Markus Falkenstätter

Markus Falkenstätter

Markus Falkenstätter ist Autor zu pharmazeutischen Themen in der Medizin-Redaktion von Medikamio. Er befindet sich im letzten Semester seines Pharmaziestudiums an der Universität Wien und liebt das wissenschaftliche Arbeiten im Bereich der Naturwissenschaften.

Mag. pharm Stefanie Lehenauer

Mag. pharm Stefanie Lehenauer

Stefanie Lehenauer ist seit 2020 freie Autorin bei Medikamio und studierte Pharmazie an der Universität Wien. Sie arbeitet als Apothekerin in Wien und ihre Leidenschaft sind pflanzliche Arzneimittel und deren Wirkung.

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