What are the contraindications for Dicyclomine (Anticholinergic medication)?

Contraindications for Dicyclomine

Dicyclomine is contraindicated in infants less than 6 months of age, nursing mothers, and patients with unstable cardiovascular status in acute hemorrhage, myasthenia gravis, glaucoma, obstructive uropathy, obstructive disease of the gastrointestinal tract, severe ulcerative colitis, and reflux esophagitis. 1

Absolute Contraindications

Dicyclomine, an anticholinergic medication commonly used for irritable bowel syndrome, has several important contraindications that must be observed to prevent serious adverse outcomes:

1. Infants under 6 months of age - Dicyclomine can cause respiratory depression and death in this population 1
2. Nursing mothers - Can pass through breast milk and affect infants 1
3. Myasthenia gravis - Anticholinergics can worsen muscle weakness 1
4. Glaucoma - Particularly angle-closure glaucoma, as anticholinergics can precipitate acute attacks 1, 2
5. Obstructive uropathy - Can worsen urinary retention 1, 3
6. Gastrointestinal obstruction - Can worsen obstruction and lead to paralytic ileus 1
7. Severe ulcerative colitis - Can precipitate toxic megacolon 1
8. Reflux esophagitis - Can worsen symptoms by reducing lower esophageal sphincter tone 1
9. Unstable cardiovascular status in acute hemorrhage - May further compromise hemodynamics 1

Relative Contraindications and Special Populations

Elderly Patients

• Elderly patients are particularly susceptible to anticholinergic side effects including:
  • Cognitive impairment
  • Urinary retention (especially males with prostatic enlargement)
  • Constipation
  • Falls due to sedation
  • Confusion and delirium 3

Patients with Prostatic Hypertrophy

• Increased risk of urinary retention due to anticholinergic effects 3
• Consider alternative treatments or concomitant alpha-blocker therapy if treatment is necessary 3

Cardiovascular Disease

• Use with caution in patients with cardiovascular disease as anticholinergics can cause tachycardia 4

Mechanism of Action and Implications

Dicyclomine has multiple mechanisms of action beyond simple anticholinergic effects:

• Anticholinergic (antimuscarinic) properties that block acetylcholine at muscarinic receptors 5, 6
• Local anesthetic properties similar to lidocaine 6
• Impairs excitation-contraction coupling in smooth muscle 6
• Inhibits release of neurotransmitters from autonomic nerves 6

These multiple mechanisms explain its efficacy in irritable bowel syndrome 7 but also account for its broad range of contraindications and side effects.

Alternative Treatment Options

For patients with contraindications to dicyclomine who require treatment for IBS:

• Other antispasmodics with fewer anticholinergic effects may be considered 4
• Tricyclic antidepressants at low doses for pain predominant IBS (avoid if constipation is a major feature) 4
• For diarrhea-predominant IBS, loperamide (4-12 mg daily) is an effective alternative 4

Clinical Pearls

• Always inquire about glaucoma history before prescribing anticholinergics like dicyclomine 2
• While anticholinergics are contraindicated in angle-closure glaucoma, they may be used with caution in open-angle glaucoma or in angle-closure glaucoma that has been treated with laser iridotomy (with ophthalmologist approval) 2
• Monitor for anticholinergic side effects: dry mouth, blurred vision, urinary retention, constipation, tachycardia, and cognitive effects
• Avoid combining with other medications that have anticholinergic properties to prevent additive effects 3

By carefully screening for these contraindications before prescribing dicyclomine, clinicians can prevent serious adverse outcomes and improve patient safety.