Stimulant laxatives: cautions and contraindications

• Main adverse effects are griping and intestinal cramps. Prolonged use can result in fluid and electrolyte imbalance and loss of colonic smooth muscle tone. This can lead to a vicious circle in which larger and larger doses are needed to produce evacuation, until eventually the bowel ceases to respond at all and constipation becomes permanent. Stimulant laxatives should only be used for a few days at most to re-establish bowel habit.
• Stimulant laxatives should be avoided in the first trimester of pregnancy and in the last few weeks, as they may stimulate uterine contractions.
• Stimulant laxatives are generally not recommended, and most are not licensed, for use in children under five years of age.
• Certain cautions should be observed in the use of anthraquinones (see below). They are secreted in breast milk and large doses may cause increased gastric motility and diarrhoea in infants; this class of laxative should therefore be avoided by breastfeeding mothers.
• Anthraquinone glycosides are excreted via the kidney and may colour the urine a yellowish-brown to red colour.