Duration of Glycerin Suppository in the Colon
Glycerin suppositories do not "stay" in the colon for an extended period—they dissolve rapidly at body temperature and typically produce a bowel movement within 15-30 minutes of insertion.
Mechanism and Onset of Action
Glycerin suppositories act as rectal stimulants through the mildly irritant action of glycerol on the rectal mucosa, stimulating peristalsis and promoting rapid evacuation. 1
- The suppository melts at body temperature after insertion into the rectum, releasing glycerol that acts locally 2, 3
- Glycerin works by drawing water into the rectum through osmotic action and directly irritating sensory nerve endings to trigger the defecation reflex 1
- The expected response time is typically within 30 minutes, with many patients experiencing evacuation within 15-30 minutes 4
Clinical Effectiveness Timeline
- In a randomized controlled trial, 51.7% of patients achieved successful evacuation within 30 minutes of suppository insertion 4
- The suppository does not remain intact—it dissolves and is expelled with the bowel movement it stimulates 2, 3
- The glycerin itself is absorbed or evacuated during the bowel movement; it does not persist in the colon 1
Clinical Context and Usage
Glycerin suppositories are recommended as first-line therapy when digital rectal examination identifies a full rectum or fecal impaction, working more quickly than oral laxatives. 1
- They are intended for short-term treatment and acute relief rather than chronic daily use 1
- The suppository must be retained in the rectum for adequate time to work—premature expulsion reduces effectiveness 5
- If no bowel movement occurs within 30-60 minutes, the suppository has likely been ineffective and alternative interventions should be considered 6
Common Pitfall
The main failure mode is premature expulsion of the suppository before it can dissolve and exert its effect—this is particularly problematic in patients with weak sphincter tone or severe impaction where the suppository cannot be retained. 5