Liquid paraffin

Class Lubricant laxative
Chemistry

Mixture of alkanes of different molecular mass, usually with carbon number over 35

Routes of administration

Oral or rectal

Absorption

Non-absorbable

Solubility

pKa > 30; not even slightly soluble in water

Distribution

Not absorbed; remains in the bowel

Metabolism

Inert; not metabolised by colonic bacteria

Elimination

Eliminated largely unchanged in the stool

Time course of action

Duration of effect depends largely on the gut motility

Target receptor

Does not bind to any receptors

Mechanism of action

By emulsifying the stool and coating the walls of the bowel, increases gut transit by decreasing the resistance to the passage of stool

Clinical effects

Decreased absorption of fat-soluble vitamins, lipid pneumonitis with aspiration, pruritis ani, accidental rectal leakage

Literature reference

Morgan (1938)

CICM details of understanding Not specifically listed in the CICM syllabus
Mentioned around Deranged Physiology
Related SAQs