Which medications are known to cause diplopia (double vision)?

Medications That Cause Double Vision (Diplopia)

Multiple medication classes can cause diplopia, with antiepileptic drugs (particularly oxcarbazepine, levetiracetam, and lamotrigine), benzodiazepines (lorazepam), selective serotonin reuptake inhibitors (sertraline), and botulinum toxin being the most commonly implicated agents.

Antiepileptic Drugs (AEDs) - Highest Risk Category

Second-generation AEDs are the most extensively documented medication class causing diplopia. Based on comprehensive analysis, the risk hierarchy from highest to lowest is 1, 2:

• Oxcarbazepine (OR 7.996) - highest risk
• Levetiracetam (OR 7.472) - second highest risk, though confidence intervals are wide
• Lamotrigine (OR 5.258) - third highest risk
• Vigabatrin (OR 3.562)
• Pregabalin (OR 3.048)
• Topiramate (OR 2.660) - also causes serious eye-related adverse events 1
• Gabapentin (OR 1.966) - tends to cause macula-related adverse events 1
• Zonisamide (OR 1.406)

Key clinical point: Lacosamide rarely causes severe eye-related adverse events, with diplopia being one of the few significant ocular effects 1. Levetiracetam specifically tends to produce ocular neuromuscular disorder-related adverse events 1.

Psychotropic Medications

Benzodiazepines

Lorazepam has documented cases of causing diplopia, though this is rarely reported in clinical practice 3. The frequency of occurrence is not well established, but clinicians should be aware of this potential adverse effect.

Selective Serotonin Reuptake Inhibitors (SSRIs)

Sertraline can cause diplopia, with documented cases showing resolution after discontinuation and recurrence upon rechallenge 4. This represents the first reported case of sertraline-induced diplopia, though citalopram (another SSRI) has also been associated with this adverse effect.

Botulinum Toxin

Botulinum toxin A (Botox) injections for facial rejuvenation or blepharospasm can cause diplopia through chemodenervation of adjacent extraocular muscle groups 5. This is a rare but recognized complication that:

• Occurs transiently
• Resolves spontaneously over 3-4 months without treatment
• Results from regeneration of inactivated proteins necessary for acetylcholine vesicle degranulation

Critical counseling point: Patients receiving botulinum toxin for cosmetic or therapeutic purposes must be informed of diplopia risk before treatment 5.

Clinical Approach to Medication-Induced Diplopia

When evaluating a patient with new-onset diplopia:

1. Obtain detailed medication history - specifically ask about recent additions or dose changes of AEDs, benzodiazepines, SSRIs, or botulinum toxin injections
2. Temporal relationship - diplopia typically develops within days to weeks of medication initiation or dose escalation
3. Consider discontinuation or dose reduction - medication-induced diplopia often resolves with drug cessation (as demonstrated with sertraline 4)
4. Monitor for spontaneous resolution - particularly with botulinum toxin, expect 3-4 month recovery period 5

Important Caveats

• The mechanism of SSRI-induced diplopia remains incompletely understood and requires further study 4
• Levetiracetam data should be interpreted cautiously given wide confidence intervals, though the signal is strong 2
• Always rule out other causes of diplopia before attributing symptoms solely to medications, as multiple etiologies may coexist 6
• Iatrogenic diplopia after eye surgery (including from anesthetic toxicity to extraocular muscles) should be distinguished from medication-induced diplopia 6