Loperamide
Class: antidiarrhoeal – peripheral opioid receptor agonist
Indications: diarrhoea, reduce number of stools in ileostomy and colostomy patients
Contraindications/cautions: diarrhoea due to infection or antibiotics
Adverse reactions: common: flatulence, constipation, abdominal distension, abdominal pain, bloating; less common: giddiness, dry mouth
Metabolism/clearance: transported out of cells by P-glycoprotein which stops it crossing the blood-brain barrier. Metabolised by oxidation but 50% excreted unchanged in faeces
Interactions:
- decreased clinical effect of loperamide with prokinetics e.g. metoclopramide/ domperidone
- CNS adverse effects may occur with P-glycoprotein inhibitors e.g. grapefruit juice, itraconazole, ketoconazole, tamoxifen
| Dosing: | |
|---|---|
| oral: | 4 mg stat then 2 mg after each loose stool (max. of 16 mg/24 hours) |
| subcut: | not available |
| rectal: | not available |
Syringe driver: not available
Mechanism of action: binds to opioid receptors in gastrointestinal tract. May also affect cholinergic receptors
Onset: 1 to 3 hours
Notes:
- may not be of benefit if patient is already taking morphine
- absorbed but doesn’t normally cross the blood-brain barrier BUT may become active in the CNS as an opioid if given with P-glycoprotein inhibitors e.g. itraconazole