From the FDA Drug Label
Nervous system—Frequent: trismus, vertigo; Infrequent: akathisia, apathy, ataxia, circumoral paresthesia, CNS stimulation, emotional lability, euphoria, hallucinations, hostility, hyperesthesia, hyperkinesia, hypotonia, incoordination, libido increased, manic reaction, myoclonus, neuralgia, neuropathy, psychosis, seizure, abnormal speech, stupor; Rare: akinesia, alcohol abuse, aphasia, bradykinesia, buccoglossal syndrome, cerebrovascular accident, loss of consciousness, delusions, dementia, dystonia, facial paralysis, feeling drunk, abnormal gait, Guillain-Barre Syndrome, hyperchlorhydria, hypokinesia, impulse control difficulties, neuritis, nystagmus, paranoid reaction, paresis, psychotic depression, reflexes decreased, reflexes increased, suicidal ideation, torticollis
Venlafaxine may cause symptoms that could be interpreted as brain fog, such as:
- Confusion
- Abnormal thinking
- Difficulty with coordination and balance
- Dizziness
- Somnolence However, brain fog is not explicitly mentioned in the drug label. 1
From the Research
Venlafaxine can cause brain fog in some individuals, as evidenced by its effects on neurotransmitters like serotonin and norepinephrine, which influence both mood and cognitive function 2. The relationship between venlafaxine and brain fog is complex, with some studies suggesting that it may impair cognitive functions such as vigilance and memory, particularly at higher doses 3, 4. However, other studies have found that venlafaxine does not significantly affect cognitive functions in healthy individuals 2. Some key points to consider when evaluating the relationship between venlafaxine and brain fog include:
- The potential for venlafaxine to cause cognitive deterioration, particularly in cases of overdose 3
- The influence of venlafaxine on neurotransmitters like serotonin and norepinephrine, which play a role in mood and cognitive function 4, 2
- The variability in individual responses to venlafaxine, with some people experiencing significant cognitive impairment and others experiencing little to no effect 5, 6 It's essential to weigh the potential benefits of venlafaxine against its potential risks, including the risk of brain fog, and to carefully monitor patients for any adverse effects 6. If you experience persistent or severe brain fog while taking venlafaxine, it's crucial to discuss this with your healthcare provider, who may recommend strategies such as adjusting the dosage or switching to an alternative medication 6.