Mineral Oil / White Petrolatum
Mineral oil is a transparent, colorless, and odorless mixture of complex hydrocarbons derived from crude petroleum. In veterinary medicine, it is a classic **lubricant laxative** used extensively in large animal practice (especially horses) for the management of large colon impactions and sand colic. In small animals, it is primarily utilized in the form of flavored petrolatum gels to manage or prevent feline trichobezoars (hairballs). Additionally, it can be administered via stomach tube to retard the gastrointestinal absorption of specific lipid-soluble toxins (e.g., metaldehyde, kerosene) by acting as a lipid sink. > **Clinical Pearl:** Heavy mineral oil is preferred over light mineral oil for pharmaceutical purposes, as it has a lower tendency to be absorbed from the gut or aspirated during administration.
Mechanism: Mineral oil and petrolatum act purely mechanically within the gastrointestinal tract: * **Lubrication:** Coats the intestinal mucosa and the fecal mass, reducing friction. * **Moisture Retention:** Creates a hydrophobic barrier that prevents the reabsorption of water from the GI tract โ increases fecal bulk and softens the stool. * **Transit Time:** The increased bulk and lubrication stimulate peristalsis โ decreases intestinal transit time. * **Toxin Sequestration:** Acts as an indigestible lipid sink in the gut lumen, trapping lipid-soluble toxins and preventing their systemic absorption.
Dosing by species
- Laxative ยท 100-500 mL ยท Stomach tube
- Laxative ยท 100-500 mL ยท Stomach tube
- Laxative ยท 2-10 mL ยท PO ยท Because of the risk for aspiration, liquid mineral oil is rarely recommended for PO administration today.
- Laxative ยท 2-6 mL ยท PO
- Laxative ยท 5 mL ยท PO ยท q24h ยท Give per day with food
- Laxative ยท 1-4 liters ยท Stomach tube
- Laxative (Adults) ยท 0.5-2 liters ยท Stomach tube
- Laxative (Calves) ยท 60-120 mL ยท Stomach tube
- Adjunctive treatment of metaldehyde poisoning ยท 8 mL/kg ยท Stomach tube ยท May be used with a saline cathartic
- Adjunctive treatment of nitrate poisoning ยท 1 liter per 400 kg body weight ยท Stomach tube
Routes of administration
Contraindications
- Patients with an increased risk of vomiting or regurgitation
- Dysphagia or swallowing difficulties
- Esophageal or gastric retention
- Hiatal hernia
- Debilitated or pregnant patients (based on human guidelines)
- Human pediatric patients under 6 years old
Adverse effects
- Lipid pneumonitis (severe, if aspirated)
- Granulomatous reactions in liver, spleen, and mesenteric lymph nodes (if absorbed)
- Anal oil leakage
- Decreased absorption of fat-soluble vitamins (A, D, E, K) with chronic use
Drug interactions
- Docusate (DSS) ยท Theoretically enhances the absorption of mineral oil, which could lead to systemic granulomatous reactions. Avoid concurrent use, though clinical significance in large animals appears low.
- Vitamins A, D, E, K ยท Chronic administration of mineral oil may decrease the absorption of fat-soluble vitamins. Administer between meals to minimize this effect.
Monitoring
- Clinical efficacy (fecal output, resolution of impaction)
- Signs of aspiration (coughing, tachypnea, dyspnea)
- Auscultation and thoracic radiographs if aspiration is suspected
Overdose
Overdose effects are generally self-limiting (e.g., diarrhea, anal leakage). The primary life-threatening risk is **aspiration**, which can lead to severe lipid pneumonitis. Chronic overdosage may cause fat-soluble vitamin (A, D, E, K) deficiency.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturerโs current label.