Is atropine contraindicated in patients with glaucoma?

Atropine Use in Patients with Glaucoma

Atropine is contraindicated in patients with narrow-angle glaucoma but can be used with caution in patients with open-angle glaucoma. 1

Types of Glaucoma and Atropine Contraindications

• Atropine is specifically contraindicated in narrow-angle (closed-angle) glaucoma as it can precipitate acute glaucoma attacks by causing pupillary dilation (mydriasis) that may block the drainage angle of the eye 2
• In open-angle glaucoma, atropine is not absolutely contraindicated but should be used with caution and with appropriate monitoring 3
• The FDA drug label for atropine explicitly lists "acute glaucoma" as a warning/precaution, indicating the risk of precipitating glaucoma attacks in susceptible individuals 1

Mechanism of Risk

• Atropine causes mydriasis (pupil dilation) and cycloplegia (paralysis of the ciliary muscle), which can:
  • In narrow-angle glaucoma: Block the trabecular meshwork drainage pathway, causing rapid and dangerous elevation of intraocular pressure 3, 4
  • In open-angle glaucoma: Potentially reduce traction on the trabecular meshwork and release pigment into the anterior chamber, which may affect aqueous outflow 5

Clinical Considerations by Route of Administration

Topical Ophthalmic Atropine

• Highest risk of causing intraocular pressure elevation due to direct ocular effects 3
• Should be avoided in patients with narrow-angle glaucoma 2
• May be used with caution in open-angle glaucoma with appropriate monitoring 5, 6

Systemic Atropine (Oral/Parenteral)

• Lower risk than direct ophthalmic application but still presents some risk of affecting intraocular pressure 1
• Contraindicated in narrow-angle glaucoma 1
• Can be used with caution in open-angle glaucoma with appropriate monitoring 3

Inhaled/Aerosolized Atropine

• Case reports exist of angle closure glaucoma precipitated by aerosolized atropine in predisposed individuals 4
• Screening for shallow anterior chambers is recommended before initiating therapy 4

Special Considerations

• For stress echocardiography procedures requiring atropine:

  • Narrow-angle glaucoma is specifically listed as a contraindication to atropine use 2
  • Recent research suggests that low-dose intravenous atropine used during dobutamine stress echocardiography may not cause significant pupillary dilation in patients without glaucoma, but caution is still warranted in glaucoma patients 7

• For myopia control in children:

  • Most studies show non-significant intraocular pressure changes with topical atropine, but monitoring is recommended due to individual variation in response 5, 6

Recommendations for Clinical Practice

• Before administering atropine in any form:

  • Screen patients for history of glaucoma and determine the specific type (narrow-angle vs. open-angle) 4
  • Consider ophthalmologic consultation before administering atropine to patients with known glaucoma 3
  • For patients with narrow-angle glaucoma, avoid atropine in all forms if possible 1
  • For patients with open-angle glaucoma, monitor intraocular pressure when atropine use is necessary 5, 3

• When atropine is absolutely necessary in a patient with glaucoma:

  • Use the lowest effective dose 3
  • Consider alternative medications when possible 3
  • Ensure close ophthalmologic monitoring 5

Remember that the contraindication is absolute for narrow-angle glaucoma but relative for open-angle glaucoma, where cautious use with appropriate monitoring may be acceptable.