Lubricant laxatives
Mineral oil is the main lubricant laxative currently in clinical use.
Pharmacokinetics
In its nonemulsified form, mineral oil is minimally absorbed; the emulsified form is about half absorbed. Absorbed mineral oil is distributed to the mesenteric lymph nodes, intestinal mucosa, liver, and spleen.
Metabolism and excretion
Mineral oil is metabolized by the liver and excreted in stool.
Pharmacodynamics
Mineral oil lubricates stool and the intestinal mucosa and prevents water reabsorption from the bowel lumen. The increased fluid content of stool increases peristalsis. Administration by enema also produces distention.
Pharmacotherapeutics
Mineral oil is used to treat constipation and maintain soft stool when straining is contraindicated, such as after a recent MI (to avoid Valsalva’s maneuver), eye surgery (to prevent increased pressure in the eye), or cerebral aneurysm repair (to avoid increased ICP).
Adverse reactions to mineral oil
Adverse reactions to mineral oil include:
- nausea and vomiting
- diarrhea
- abdominal cramping.
Impacting impaction
Administered orally or by enema, this lubricant laxative is also used to treat the patient with fecal impaction.
Drug interactions
Mineral oil can interact with other drugs.
- Mineral oil may impair the absorption of many oral drugs, including fat-soluble vitamins, hormonal contraceptives, and anti-coagulants.
- Mineral oil may interfere with the antibacterial activity of nonabsorbable sulfonamides. To minimize drug interactions, administer mineral oil at least 2 hours before these medications
Comments
Post a Comment