How should I insert a rectal suppository in a term newborn (≥37 weeks gestation, ≥2 kg) after a clinician has prescribed the medication, dose, and duration?

How to Insert a Rectal Suppository in a Term Newborn

Insert the suppository blunt end (base) first into the rectum, not the pointed end, as this method achieves better retention and requires less digital manipulation of the anal canal. 1

Preparation and Positioning

• Position the infant on their side with knees flexed toward the chest, or supine with legs elevated 2
• Wear gloves and ensure the suppository is at room temperature for easier insertion 2
• Lubricate the suppository with water-soluble lubricant if needed to facilitate insertion 2

Insertion Technique

Correct Orientation

• Insert the blunt (base) end first, not the pointed end 1
• This counterintuitive method was demonstrated in a study of 100 subjects (60 adults, 40 infants and children) where base-first insertion achieved easier retention in 98% of cases 1
• Base-first insertion resulted in 0% expulsion rate compared to 3% with apex-first insertion 1
• This method requires finger insertion into the anal canal in only 1% of cases versus 83% with pointed-end insertion 1

Insertion Depth and Technique

• Gently insert the suppository past the internal anal sphincter (approximately 1-2 cm in newborns) 2, 3
• The reversed vermicular contractions and pressure gradient of the anal canal naturally press the suppository inward when inserted base-first 1
• Hold the buttocks together for 1-2 minutes after insertion to prevent immediate expulsion 2

Common Pitfalls

The "Commonsense" Error

• Despite 86.9% of lay subjects and 84.6% of medical personnel inserting suppositories pointed-end first based on "commonsense," this method is actually less effective 1
• Manufacturer instructions often recommend pointed-end insertion, but this conflicts with the best available clinical evidence 4

Timing Considerations

• Avoid insertion immediately before or after feeding to minimize the risk of defecation-related expulsion 3
• Absorption can be interrupted by defecation, so timing relative to bowel movements is important 3

Pharmacokinetic Considerations for Newborns

• Rectal absorption in neonates occurs rapidly from aqueous solutions but more slowly from suppository bases 3
• The lower rectum connects directly to systemic circulation, potentially avoiding some hepatic first-pass metabolism 3
• Retention is critical for adequate drug absorption, making proper insertion technique essential 2, 3

Special Considerations for Specific Medications

Emergency Medications

• Rectal administration is particularly valuable for unconscious or vomiting infants where oral administration is impossible 2
• Diazepam suppositories can achieve rapid absorption for acute seizure control when inserted correctly 3

Safety Note

• The rectal route uses excipients generally regarded as safe, with low manufacturing costs 2
• However, certain medications (like Kayexalate) should be avoided or used with extreme caution in neonates due to risk of intestinal hemorrhage 5