Is Canker Sore a Typical Side Effect of Venlafaxine?
No, canker sores (aphthous ulcers) are not a recognized or typical side effect of venlafaxine. The established adverse effect profile of venlafaxine does not include oral ulcerations.
Documented Adverse Effects of Venlafaxine
The well-characterized side effects of venlafaxine include 1:
- Gastrointestinal effects: Nausea (most common), vomiting, dry mouth, abdominal discomfort, diarrhea, constipation, decreased appetite
- Neurological effects: Dizziness, headache, tremor, insomnia, somnolence
- Other common effects: Diaphoresis (sweating), weight loss
- Cardiovascular effects: Sustained hypertension, increased blood pressure and pulse 1
Nausea is notably the most common adverse effect, with venlafaxine having a higher incidence of nausea and vomiting compared to other SSRIs 1. In clinical trials, nausea and vomiting were the most frequent reasons for treatment discontinuation 1.
Serious but Uncommon Adverse Effects
Potentially serious adverse effects that have been documented include 1:
- Suicidal thinking and behavior (particularly in patients under age 24)
- Behavioral activation/agitation, hypomania, mania
- Sexual dysfunction
- Seizures
- Abnormal bleeding
- Serotonin syndrome
- Discontinuation symptoms (particularly prominent with venlafaxine due to its short half-life)
- Greater suicide risk compared to other SNRIs 1
- Overdose fatalities 1
Rare hepatotoxicity can occur, though routine liver monitoring is not required in patients without risk factors 2.
Drug-Induced Oral Ulcerations: Not Associated with Venlafaxine
While certain medications can cause oral ulcerations, venlafaxine is not among the documented culprits 3. Drugs known to cause solitary oral ulcerations include 3:
- NSAIDs: Diclofenac, flurbiprofen, indomethacin, naproxen
- Rheumatoid arthritis therapies: Azathioprine, methotrexate, penicillamine, gold compounds
- Cardiovascular agents: ACE inhibitors (captopril, enalapril), angiotensin-2 receptor antagonists (losartan), nicorandil
- Other antidepressants: Fluoxetine, lithium (but not venlafaxine)
- AIDS therapies: Foscarnet, zalcitabine
Clinical Implications
If a patient on venlafaxine develops canker sores, alternative etiologies should be investigated 4:
- Trauma to oral mucosa
- Nutritional deficiencies (hematinic deficiencies)
- Gastrointestinal diseases (celiac disease, inflammatory bowel disease)
- Immunologic factors
- Stress, hormonal changes
- Food hypersensitivities
- Associated systemic disorders (Behçet's disease, cyclic neutropenia, HIV disease)
The temporal relationship between starting venlafaxine and developing oral ulcers would be coincidental rather than causal, as this is not a recognized adverse effect in clinical trials or post-marketing surveillance 1, 5.