What are the next steps for a patient who develops dilated pupils after taking the first dose of escitalopram (Lexapro), an antidepressant?

Management of Dilated Pupils After First Dose of Escitalopram

Continue escitalopram at the current dose and reassure the patient that pupillary dilation is a known, benign side effect that typically does not require discontinuation of therapy. 1, 2

Immediate Assessment

Perform a focused pupillary examination to confirm:

• Bilateral vs. unilateral dilation – medication-induced mydriasis is typically bilateral 1
• Preservation of light reactivity – reactive pupils differentiate benign drug effect from neurological emergencies 1
• Absence of fixed, non-reactive pupils – which would suggest serious pathology requiring emergent evaluation 3
• No accompanying neurological symptoms such as severe headache, confusion, altered mental status, or focal deficits 1

Mechanism and Clinical Context

• Escitalopram can cause mild pupillary dilation through serotonergic effects on pupillary control, which is explicitly acknowledged in FDA labeling 2
• The FDA specifically warns that pupillary dilation may trigger angle-closure glaucoma in susceptible individuals with anatomically narrow angles who lack a patent iridectomy 2
• Pre-existing open-angle glaucoma is NOT a risk factor for angle-closure glaucoma 2
• This side effect is generally transient and may resolve as tolerance develops 1

Management Algorithm

If pupils are dilated but reactive with no other symptoms:

• Continue escitalopram at current dose (typically 10 mg/day starting dose) 3, 1
• Reassure the patient about the benign nature of this finding 1
• Document baseline pupillary findings for future comparison 1
• Schedule follow-up within 1-2 weeks to reassess 1

If patient has risk factors for angle-closure glaucoma:

• Consider ophthalmology referral to determine anatomical susceptibility to angle closure 2
• Patients may benefit from prophylactic iridectomy if anatomically susceptible 2

Red flags requiring immediate medical attention:

Instruct the patient to seek emergency care if they develop:

• Fixed (non-reactive) pupils 1
• Sudden severe headache 1
• Confusion or altered mental status 1
• Visual changes, eye pain, or halos around lights (suggesting acute angle-closure) 2

Monitoring and Follow-Up

• Reassess pupillary response at next visit (1-2 weeks) 1
• Monitor for other SSRI side effects including nausea (typically mild and transient), insomnia, diarrhea, or sexual dysfunction 3, 4
• Most adverse effects emerge within the first few weeks of treatment 1, 4

If pupillary dilation persists beyond 4 weeks:

• If therapeutic benefit is present and patient tolerates well: maintain current dose 1
• If bothersome AND other side effects are problematic: consider switching to alternative SSRI 1
• Isolated pupillary dilation alone is NOT an indication to discontinue if otherwise well-tolerated 1

Important Clinical Considerations

• Escitalopram has a favorable safety profile with most side effects being mild to moderate 1, 4, 5
• The recommended starting dose is 10 mg/day with maximum dose of 20 mg/day in adolescents and adults 3
• Therapeutic effects may be noticed within 1-4 weeks, but patients should continue therapy as directed 2, 4
• Escitalopram is highly selective for serotonin reuptake with minimal effects on other neurotransmitter systems 4, 5

Common Pitfall to Avoid

Do not discontinue escitalopram solely based on dilated but reactive pupils – this is a recognized, benign side effect that does not indicate serious pathology when pupils remain reactive and no other concerning symptoms are present 1, 2. Premature discontinuation may deprive the patient of effective antidepressant therapy 3, 4.