Can metoprolol (beta-blocker) cause ptosis?

Metoprolol and Ptosis: Potential Association

Metoprolol can cause ptosis as a rare central nervous system side effect, particularly in elderly patients or those sensitive to beta-blockers' CNS effects.

Mechanism and Evidence

Beta-blockers like metoprolol can cause various central nervous system effects, with visual disturbances being among the reported adverse reactions. While ptosis specifically is not extensively documented in major guidelines, there is evidence supporting metoprolol's potential to cause visual and neurological side effects:

• Case reports have documented visual hallucinations with metoprolol that resolved upon discontinuation of the medication 1
• CNS complications including visual disturbances have been reported, particularly in elderly patients 2
• The risk of CNS side effects from beta-blockers correlates with the drug's lipophilicity, with metoprolol being moderately lipophilic 2

Risk Factors for Metoprolol-Induced Ptosis

Several factors may increase the risk of developing ptosis while on metoprolol:

• Advanced age (particularly >70 years)
• Higher doses of metoprolol
• Concurrent use of other medications affecting CNS function
• Pre-existing neurological conditions
• Renal or hepatic impairment (affecting drug clearance)

Diagnostic Approach

When evaluating ptosis in a patient taking metoprolol:

1. Determine the temporal relationship between starting metoprolol and onset of ptosis

2. Rule out other common causes of ptosis:

   • Myasthenia gravis
   • Oculomotor nerve palsy
   • Horner's syndrome
   • Mechanical ptosis (age-related)
   • Thyroid eye disease 3

3. Assess for other concurrent beta-blocker side effects:

   • Fatigue
   • Dizziness
   • Sleep disturbances
   • Visual hallucinations

Management Algorithm

1. If ptosis is mild and not affecting vision or quality of life:

   • Continue monitoring
   • Consider dose reduction if clinically appropriate

2. If ptosis is moderate to severe or affecting quality of life:

   • Consider switching to a less lipophilic beta-blocker (e.g., atenolol)
   • Case 3 from the literature showed resolution of visual disturbances within 4 days after switching from metoprolol to atenolol 1

3. If cardiovascular condition requires metoprolol specifically:

   • Weigh benefits against risks
   • Consider ophthalmology consultation for ptosis management options

4. If discontinuation is necessary:

   • Taper gradually to avoid rebound hypertension
   • Monitor for resolution of ptosis (typically occurs within days to weeks)
   • Select an alternative agent based on the underlying cardiovascular condition

Important Considerations

• Ptosis may be underreported as patients might not associate it with their medication or may attribute it to aging
• Healthcare providers may not recognize this connection, delaying appropriate management
• Resolution typically occurs within days to weeks after discontinuation or switching to a less lipophilic beta-blocker
• Document the adverse effect to prevent future re-challenge with the same medication

While the direct evidence linking metoprolol to ptosis specifically is limited, the documented CNS effects and visual disturbances support a plausible connection that warrants clinical attention when evaluating patients with new-onset ptosis while on this medication.