Drug-Induced Oral Reactions – A Bitter Truth

Our perception of reality relies entirely on our five senses – hearing, sight, smell, taste, and touch – first identified by Aristotle. When one or more of these senses is impaired, it can cause significant discomfort. If this impairment results from an adverse drug reaction, the concern becomes even more critical. In this article, we explore several cases uncovered by the DrugCard platform in medical literature, specifically focusing on drug-induced oral reactions and their impact on taste perception.

Understanding Drug-Induced Oral Reactions

Adverse drug reactions (ADRs) present in various ways, influenced by factors such as medication type, dosage, and individual patient characteristics. These reactions can occur rapidly or persist for several days after administration. Most drug-induced oral reactions improve when patients discontinue the medication or reduce the dosage. Typically, symptoms emerge within the first or second week of treatment, often correlating with dose-dependent toxicity.

Black Hairy Tongue (BHT) and Olanzapine

Black hairy tongue (BHT) is a benign, self-limiting condition characterized by hypertrophied and elongated filiform papillae on the tongue’s surface. In one case, a woman with hebephrenic schizophrenia developed BHT after increasing her olanzapine dosage to 20 mg daily. The timing suggests a dose-dependent relationship between olanzapine and BHT. Although the exact cause of BHT remains unclear, antipsychotics and cannabinoids have been implicated, likely due to the xerostomia (dry mouth) they induce. In this case, the condition resolved after discontinuing olanzapine and cannabinoids and improving oral hygiene.

Burning Mouth Syndrome: A Drug-Induced Oral Reaction Linked to Statin Use

Burning mouth syndrome (BMS) is a painful condition linked to small fiber neuropathy, affecting sensory and autonomic nerve fibers. Symptoms include burning, tingling, and stabbing discomfort. One reported case involved a 35-year-old male with type IV hyperlipoproteinemia who developed tongue dysesthesias just seven days after starting atorvastatin (20 mg daily). A neurological examination found no abnormalities besides the tongue’s burning sensation. Symptoms resolved within three weeks after discontinuing atorvastatin, suggesting a direct link between statin use and drug-induced oral reactions in this patient.

A Drug-Induced Oral Reaction Associated with Sertraline Use

Antidepressants that inhibit serotonin reuptake cause oral ulcers, likely by affecting salivary gland function. Dry mouth increases susceptibility to oral trauma, leading to ulcer formation. A case series highlighted two patients who developed oral ulcers after taking sertraline, emphasizing the need for vigilant monitoring.

Case 1: Single-Episode Depressive Disorder

A woman diagnosed with moderate single-episode depressive disorder was prescribed escitalopram (10 mg) with minimal improvement. She switched to sertraline (50 mg), which was gradually increased to 150 mg over two months. Two weeks after the dose increase, she developed painful oral ulcers, which worsened over time. The ulcers resolved after discontinuing sertraline but reappeared when the dose increased. The Naranjo Adverse Drug Reaction Probability Scale score of 8 indicated a “probable” relationship between sertraline and drug-induced oral reactions.

Case 2: Adjustment Disorder

A patient diagnosed with adjustment disorder started sertraline (50 mg) and developed oral ulcers within four days. She noticed improvement after skipping a dose, but the ulcers reappeared upon resuming treatment. The ulcers resolved within three days of stopping sertraline. The Naranjo scale yielded a score of 11, indicating a “definitive” probability of drug-induced oral reactions.

Conclusion

Drug-induced oral reactions can significantly affect a patient’s quality of life, sometimes in ways that go unnoticed or misunderstood. Though rare, conditions like BHT, BMS, and oral ulcers show how even subtle side effects can have a profound impact. By constantly scanning and analyzing medical literature, pharmacovigilance helps uncover hidden or emerging drug safety signals that might otherwise be overlooked. In turn, healthcare professionals should remain vigilant, ensuring timely intervention and appropriate patient care.