Castor oil is one of the oldest purgatives. It is a bland vegetable oil obtained from the seeds of Ricinus communis.
It mainly contains ricinoleic acid triglycerides, a polar long-chain fatty acid.
Castor oil is hydrolyzed in the ileum by lipase, ricinoleic acid, and glycerol. Ricinoleic acid, being polar, will be poorly absorbed.
Mechanism of action.
- It irritates the mucosa and stimulates intestinal contractions.
- It also decreases intestinal absorption of water and electrolytes and enhances secretion by a detergent-like action on the mucosa.
Clinical uses.
- Used as a purgative during constipation.
- Colonic evacuation
Adverse effects
- Structural damage to the villous tips in the intestines.
- Dehydration and after-constipation.
- Hypotension, dizziness, and electrolyte imbalance.
- Pelvic congestion.
- Abdominal cramping
- Nausea and vomiting.
Contraindication.
- Hypersensitivity to the drug.
- GI obstruction or perforation, severe impaction,
- Symptoms of appendicitis or acute surgical abdomen,
- Ulcerative colitis
- Rectal fissures
- Avoid pregnancy as it can induce premature labor.
Dosage.
- 15–25 ml (adults) and 5–15 ml (children) are usually taken in the morning. Its purgation occurs in 2–3 hours—motion is semifluid and often accompanied by griping.
