What is a suppository?

Suppositories are designed for anal administration and usually consist of the active drug(s) and a base which melts at room temperature. Once the suppository has been rectally administered, the base will then break down and the drug will be released.

Most suppositories are prescribed for local effects such as treating constipation or haemorrhoids. The anal route however provides an excellent route for drug absorption and therefore can be used in patients with swallowing difficultiesor for drugs where avoidance of the stomach is preferable e.g. NSAIDs.
Additionally by avoiding the stomach, the drug misses the liver and therefore in many cases more of the drug will get into the system and a lower dose can be administered. For this reason, it is important to check the bioavailability of a suppository compared to a tablet when swapping between the two.

Except in the case of constipation, it is important to administer suppositories after bowels have been evacuated otherwise an evacuation itself could cause the suppository to be expelled prematurely.