Medications That Can Cause Phantosmia
Based on the available evidence, there are no well-established medications that directly cause phantosmia as a documented adverse effect. The literature on phantosmia primarily identifies it as an idiopathic condition or one associated with post-traumatic/post-infectious olfactory loss rather than medication-induced 1, 2.
Key Clinical Evidence
Limited Drug-Related Causation
Rare causes of phantosmia have been reported to include side-effects of drugs, but specific medications are not identified in the available high-quality evidence 2.
The most comprehensive study following 44 patients with idiopathic phantosmia over 10 years found that more than 50% experienced improvement or resolution after 5 years, with no patients developing severe health conditions, suggesting phantosmia is generally a benign symptom rather than a medication-related warning sign 1.
Treatment Rather Than Causation
Interestingly, the evidence focuses on medications that treat phantosmia rather than cause it. Thioridazine and haloperidol have been shown to successfully inhibit phantom tastes and smells, with objective fMRI evidence demonstrating reduced brain activation in sensory-specific regions 3.
This suggests that antipsychotics may modulate central processing abnormalities underlying phantosmia, supporting the theory that phantosmia is related to central nervous system processing problems rather than peripheral medication effects 3, 4.
Clinical Implications
What This Means for Practice
When a patient presents with phantosmia, medication review is reasonable but unlikely to identify a causative agent based on current evidence 1, 2.
The focus should be on ruling out post-traumatic, post-infectious, or rare causes (brain tumors, intracerebral hemorrhage, paraneoplastic syndromes, psychiatric disorders) rather than assuming medication causation 2.
Reassurance is appropriate: idiopathic phantosmia improves or disappears in almost two-thirds of patients after more than 5 years and does not predict serious neurological disease like Parkinson's 1.