Anti-motility agents, also known as anti-diarrhoeal medications, are used to manage diarrhoea by reducing intestinal motility. These medications help to alleviate symptoms and improve stool consistency.
Loperamide (Imodium)
- Mechanism of Action:
- Loperamide works by binding to opioid receptors in the intestinal wall, which inhibits the release of acetylcholine and prostaglandins. This action reduces peristalsis (wave-like muscle contractions) and increases the transit time of bowel contents, allowing more water and electrolytes to be absorbed, resulting in firmer stools.
- Uses:
- Acute Diarrhoea: Effective for treating acute diarrhoea in adults and children.
- Chronic Diarrhoea: Can be used for chronic diarrhoea associated with conditions such as inflammatory bowel disease or short bowel syndrome.
- Traveller’s Diarrhoea: Often used for the symptomatic relief of traveller’s diarrhoea.
- Considerations:
- Should not be used in cases of bacterial enterocolitis, pseudomembranous colitis, or acute dysentery, as slowing down intestinal motility may worsen these conditions.
- Ensure adequate hydration.
- Side Effects:
- Constipation
- Abdominal pain
- Dizziness
- Rarely, paralytic ileus and toxic megacolon
Diphenoxylate and Atropine (Lomotil)
- Mechanism of Action:
- Diphenoxylate is an opioid agonist that slows intestinal motility, similar to loperamide. Atropine is added in subtherapeutic amounts to discourage abuse and overdose of diphenoxylate. The combined effect reduces bowel movements and improves stool consistency.
- Uses:
- Acute Diarrhoea: Used for the symptomatic treatment of acute diarrhoea.
- Chronic Diarrhoea: Can be used for chronic diarrhoea in certain cases under medical supervision.
- Considerations:
- Not recommended for use in children under two years of age.
- Caution is advised in patients with severe liver disease.
- Monitor for signs of central nervous system depression, especially in higher doses.
- Side Effects:
- Drowsiness
- Dry mouth
- Blurred vision
- Constipation
- Urinary retention
Codeine Phosphate
- Mechanism of Action:
- Codeine is an opioid that binds to receptors in the central and peripheral nervous system. This action decreases the tone and frequency of bowel contractions, leading to reduced bowel movements.
- Uses:
- Diarrhoea: Used for short-term relief of diarrhoea.
- Pain Relief: Often prescribed for mild to moderate pain, which can be an additional benefit if diarrhoea is associated with painful conditions.
- Considerations:
- Risk of dependency with prolonged use.
- Not recommended for children or individuals with a history of substance abuse.
- Should be used under strict medical supervision, especially in the elderly or those with compromised respiratory function.
- Side Effects:
- Constipation
- Drowsiness
- Nausea
- Risk of dependency and addiction
Norfloxacin-Tinidazole (Norflox TZ)
Mechanism of Action:
Norfloxacin is a fluoroquinolone antibiotic that inhibits bacterial DNA gyrase and topoisomerase IV, enzymes necessary for bacterial DNA replication, transcription, repair, and recombination. Tinidazole is an antiprotozoal and antibacterial agent that works by causing DNA strand breakage and inhibiting nucleic acid synthesis.
Uses:
- Bacterial Diarrhoea: Effective for treating diarrhoea caused by bacterial infections such as enteric pathogens.
- Giardiasis and Amoebiasis: Tinidazole is effective against protozoal infections, including Giardia lamblia and Entamoeba histolytica.
- Traveller’s Diarrhoea: Often prescribed for traveller’s diarrhoea caused by bacterial or protozoal pathogens.
Considerations:
- Allergies: Not recommended for individuals with a known allergy to fluoroquinolones or nitroimidazoles.
- Pregnancy and Breastfeeding: Should be used with caution in pregnant or breastfeeding women.
- Resistance: Overuse of antibiotics can lead to resistance; therefore, it should be used judiciously and only when bacterial infection is confirmed or highly suspected.
Side Effects:
- Nausea and vomiting
- Diarrhoea or constipation
- Headache and dizziness
- Photosensitivity (sensitivity to sunlight)
- Rarely, tendon rupture (with fluoroquinolones)