Does it matter which way up a rectal suppository is inserted?

EXPERT COMMENT

Rectal suppositories are conveniently shaped medicated solid preparations for insertion into the rectum.  They can vary in weight and usually consist of solid vegetable oil that dissolves at body temperature. Suppositories are manufactured in a torpedo shape with a pointed end (apex) and a blunt end. The blunt end is often concave forming a useful indention for the tip of a finger to push against.

The rectal route of drug medication is relatively painless and particularly useful for patients who are fasting or nil-by-mouth before or after surgery and for patients who are unable to tolerate oral medication

due to nausea and or vomiting. Suppositories also provide a useful route for medication in children who have needle phobia. Suppositories may be used for both local and systemic effect.

Historically suppositories were inserted pointed end first until the publication of a small study by Abd-El-Maeboud et al (1991) who recommended that suppositories were inserted blunt end first. The research suggests that suppository retention is more easily achieved if suppositories are inserted blunt end first because the squeezing action of the anal sphincter against the apex pushes (sucks) the suppository into the rectum. The research was pivotal in informing clinical practice culminating in  clinical text books advocating a blunt end in first for suppository insertion.

However, if a suppository for local effect is inserted blunt end first using the anal sphincter to assist with insertion there is no guarantee that the suppository will be in contact with the bowel wall. Suppositories need body heat in order to dissolve and become effective. This could subject the patient to an ineffective, undignified and invasive procedure. 

On the other hand, patients administering their own suppository may find blunt end more acceptable as there no need to insert the finger into the anal canal to push it in. This lends weight to inserting the blunt end first - especially if the suppository is for a systemic effect, as rectal absorption is more effective lower in the rectum as veins draining from this part of the rectum join the internal iliac veins. This means medication returns directly to the inferior cava, bypassing the portal circulation.

Gaye Kyle is the chair of the ACA education committee