Rectal administration of drugs can be effective in selected patients. Warren made recommendations to ensure proper drug administration via this route. The author is from Michigan State University in East Lansing.

Conditions that may interfere with rectal drug administration:

(1) diarrhea

(2) constipation

(3) rectal bleeding

(4) hemorrhoids or rectal fissures




sufficient moisture to dissolve a solid drug formulation

If the rectal mucosa is dry and/or moisture is a concern, then insert 10 mL of water to aid dissolution and absorption. A liquid or rectal dosage formulationmay be better.

volume of material inserted

Inserting more than 60 mL of material at one time may trigger bowel evacuation.

depth to insert medications

Insert to the length of 1 finger. Insertion too high can result in drug being absorbed into the superior rectal vein with drainage to the liver which may impact drugs with high first pass metabolism in the liver.

number of pills and tablets inserted

If multiple drugs are to be inserted consider placing in a gelatin capsule to reduce the number of insertions required

drug formulation

Avoid enteric coated pills or tablets. Avoid pills or tablets that take too long to dissolve.

rectal irritation

Monitor the anus and rectal mucosa for signs of excessive irritation. Limit repeated use of drugs using alcohol or solubilizing agents that may irritate the mucosa.

variation in amount of drug absorbed

Monitor the patient for drug effect and for signs of toxicity. Consider therapeutic drug monitoring if appropriate.

patient or family dislike for the rectal route

Educate the patient and family about why this is being done. Take steps to protect the patient's dignity and modesty. Consider alternatives.


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