VPT 311: General and Systemic Veterinary Pharmacology (2+1)

LUBRICANT PURGATIVES

• Lubricants, mineral oil (liquid petroleum) and white petroleum lubricate and soften feces.
• Liquid paraffin is a viscous liquid; a mixture of petroleum hydrocarbons. It was introduced as a laxative earlier. It is pharmacologically inert. When taken for 2-3 days, it softens stools and is said to lubricate hard scybali by coating them.
• Dose: 15-30 ml /day oil as such or in emulsified form in dog
  

Disadvantages

• It will be very bland and unpleasant to swallow because of oily consistency
• Small passes into the intestinal mucosa, carried into the lymph and may produce foreign body granuloma in the intestinal submucosa, mesenteric lymph nodes, liver and spleen.
• Probalility of causing lipid pneumonia because of trickling into lungs while swallowing
• Carries fat soluble vitamins with it into the stools leading to deficiency
• Leakage of the oil past anal sphincter may embarrass and stain the floor
• May interfere with healing in the anoractal region.

Hence advisable for occasional use and that too postoperatively.

Surfactants

• Docusates is an anionic surfactant that acts in the large bowel to hydrate and soften feces by an emulsifying action.
• It causes net water accumulation in the intestinal lumen by an action on the intestinal mucosa. It emulsifies the colonic contents.
• Being a detergent, it can disrupt the mucosal barrier and enhance absorption of may nonabsorbable drugs , e.g liquid paraffin – should not be combined with it. Eg: Cellubril, Laxicon as capsules
• Dose: 100-200 mg /day; acts in 1-3 days. It is a mild laxative; specially indicated when straining as t stools must be avoided.
• Cramps and abdominal pain can occur. It is bitter in taste. Liquid preparations may cause nausea and is hepatotoxic on prolonged usage.