What Are Oral Drug Reactions?
Several systemic factors may be known to be contributing risk factors or involved in the pathogenesis of oral diseases or conditions. Among those causes, the common is the intake of drugs prescribed for systemic or local health conditions.
Though not elucidated in detail in medical literature, the pathogenesis of oral adverse reactions related to the intake of medications still remains a common complaint from patients on regular systemic medications. According to dental literature statistics, nearly 99 % of systemic diseases are associated with nearly one or more oral manifestations. These can be diagnosed by an oral physician during a routine dental examination even before the general physician because of the oral manifestations associated with systemic drugs. These reactions can be categorized based on their location in the oral cavity :
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Oral mucosa and tongue.
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Periodontal tissues.
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Dental structures (dentition or teeth, salivary glands).
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Lips and palate.
The drugs used for systemic therapy can hence have the potential to commonly cause:
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Taste disturbances.
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Drug-induced oral infections.
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Facial edema.
How Are the Drug-Induced Adverse Oral Manifestations Classified?
Let us look into the detrimental effects of commonly used systemic drugs on oral health. These effects listed below are found only in a few cases as it depends upon the systemic health condition of the individual:
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Oral Pigmentation - This abnormal pigmentation may result from either local or systemic medications like Amiodarone, antimalarials, Busulfan, Clofazimine, and Cyclophosphamide, among others. Discoloration would potentially occur after direct contact following systemic absorption of these drugs. Discoloration of the oral mucosa would be possible in some patients because of the deposition of pigmented drug metabolic products.
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Aspirin Causing Ulcerations - Drugs including anti-neoplastic drugs such as Methotrexate, 5-Fluorouracil, barbiturates, tetracyclines, nonsteroidal anti-inflammatory drugs (NSAIDs), Dapsone, Meprobamate, Methyldopa, Penicillamine, Propranolol, Spironolactone, Thiazides, Tolbutamide, Alendronate, and Phenytoin mostly because of the presence of compounds containing Aspirin, they can potentially induce oral cavity ulcerations.
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Aphthous–Like Ulcerations - These are oral ulcerations resulting from various medications, mainly the nonsteroidal anti-inflammatory drug family (NSAIDs), Azathioprine, Losartan, and gold compounds.
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Burning Mouth Syndrome - This syndrome can occur in connection with the use of certain drug therapists either because of treatment for psychogenic diseases, hormonal disorders, deficiencies or folate iron and pyridoxine, or from hypersensitivity reactions to dental materials. The most common medications that produce such side effects are ACE (angiotensin-converting enzyme) inhibitors, systemic antibiotics, hormone replacement therapy drugs, and antidepressants.
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Glossitis - Glossitis is inflammation of the tongue that may result from common drug intake of local antibiotics and corticosteroids to drugs like Methotrexate and tricyclic antidepressants.
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Epithelial Necrosis and Ulcerations- These can be caused by the direct application of over-the-counter medications like Aspirin, Hydrogen peroxide, potassium compounds, and phenol compounds that can potentially cause cell death or necrosis of less immune regions of the oral mucosa.
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Black Hairy Tongue - Black hairy tongue may be commonly observed during a routine dental examination. Upon eliciting a patient history, the dentist may find its potential linkage to the administration of oral antibiotics, corticosteroids, sulfonamides, and also due to exposure to tobacco or a history of chronic smoking.
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Drug-Induced Gingival Overgrowth - One of the most common gingival diseases linked to several drugs such as calcium channel blockers, dihydropyridines, Cyclosporine, anti-epileptics like Phenytoin, and Sodium valproate is gingival overgrowth. Diffuse, non-malignant, or benign enlargement or overgrowth is a common manifestation of gingival tissues in patients who are on Phenytoin drug therapy. Also, in recent decades, calcium channel blockers (members of the dihydropyridine medications), Cyclosporine, and antiepileptic drugs like sodium valproate have been found to be implicated in detrimental oral reactions.
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Xerostomia or Dry Mouth - This common finding is associated with more than 500 medications ranging from antidepressants and antipsychotic drugs to antihypertensives, antihistamines, anticholinergics, and decongestants.
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Contact Allergy - These are severe allergic reactions that may be specific, nonspecific, or generalized. They may traumatize the gums, palate, lips, tongue, and buccal mucosa. Common effects like oral bleeding, oral ulcerative and erosive lesions, and breathing difficulties that may occur within 24 hours of ingesting the medication should be immediately first reported to the healthcare provider or physician post which the physician would withdraw that medication, and a suitable substitute drug therapy would be accommodated. Drugs that are capable of causing contact allergy are antibiotics, food additives, mouthwashes, kinds of toothpaste, cosmetics, dental materials, and topical steroids.
What Is the Differential Diagnosis of Drug-Induced Adverse Oral Manifestations?
Oral drug reactions would be either clinical, histopathologic, or even immunopathologic. Because of the oral drug effects bearing close resemblance to vesiculobullous lesions, papulosquamous lesions such as lichen planus, erythema multiforme (EM), pemphigoid, pemphigus vulgaris, and lupus erythematosus (LE), they should be differentially diagnosed from these well-recognized lesions that occur due to drug-induced oral inflammation or trauma. For diagnosis of these vesiculobullous lesions or other red and white lesions of the oral cavity (that would potentially resemble oral drug reactions but would be because of different pathogenesis), the dentist or the maxillofacial surgeon can perform a tissue biopsy for histopathologic examination of the lesion tissue.
Conclusion
Knowledge of drug-induced adverse effects on the oral cavity helps healthcare professionals diagnose oral diseases and refer them to the dentist or vice versa, in easy administration or alternative drug therapy to improve patient compliance. This also helps health practitioners to influence a more rational use of drug therapies in any systemic or local health condition. Early recognition and diagnosis of drug-induced oral lesions and detrimental effects are important for improving treatment prognosis and limiting complications. The physician can, in collaboration with the dentist, decide to reduce the minimum dose of the drug causing oral manifestations or switch over to alternative drug regimens depending on the severity of the patient's oral symptoms.
