What are the oral manifestations of drugs?: A Comprehensive Guide

October 11, 2025 •

5 min read

According to the American Academy of Family Physicians, all of the ten most commonly prescribed medications can have adverse effects on the mouth. Awareness of what are the oral manifestations of drugs is crucial for healthcare providers and patients alike to prevent complications and maintain overall oral health.

Quick Summary

This article explores the diverse oral side effects of various medications, such as dry mouth, gum overgrowth, taste changes, and mucosal reactions. It discusses the drugs commonly associated with these issues, their underlying mechanisms, and effective management strategies.

Key Points

Dry Mouth (Xerostomia): One of the most common drug-induced oral side effects, caused by hundreds of medications and increasing the risk of tooth decay and infections.
Gingival Enlargement: Certain anticonvulsants, calcium channel blockers, and immunosuppressants can cause gum tissue overgrowth, which is often exacerbated by poor oral hygiene.
Oral Mucosal Reactions: Drugs can cause a variety of mucosal issues, including ulcers, lichenoid eruptions, and pigmentation, sometimes resembling more severe systemic diseases.
Altered Taste (Dysgeusia): Many medications can cause a distorted or unpleasant taste sensation, which can negatively impact a patient's appetite and nutrition.
Increased Risk of Infection: Medications that cause dry mouth, suppress the immune system, or alter the oral microbiome can lead to opportunistic infections, such as oral candidiasis (thrush).
Serious Hard Tissue Damage: Bisphosphonates and other drugs can cause medication-related osteonecrosis of the jaw (MRONJ), a serious condition involving jawbone exposure and necrosis.

Adverse drug reactions can affect any part of the body, and the oral cavity is a frequent site for these unwanted side effects. Given that many patients, particularly older adults, take multiple medications (a practice known as polypharmacy), the risk of experiencing these issues is significant. Understanding the range of potential oral manifestations of drugs is essential for accurate diagnosis and effective management, which often involves collaboration between medical and dental professionals.

Xerostomia (Dry Mouth) and Salivary Gland Disturbances

Xerostomia, or dry mouth, is one of the most common oral side effects of medication, with over 500 drugs potentially contributing to the condition. A reduction in saliva flow can have serious consequences, including increased risk of tooth decay, gum disease, and oral infections like candidiasis.

Many medications exert an anticholinergic or sympathomimetic effect, which directly reduces salivary flow. Drug-induced xerostomia can be especially prevalent in the elderly due to their increased use of multiple medications.

Medications that frequently cause dry mouth:

Antidepressants (especially tricyclic antidepressants)
Antihistamines
Antihypertensives (diuretics, beta-blockers)
Antipsychotics
Sedatives and anxiolytics
Certain pain medications, such as opioids

In addition to dry mouth, some drugs can also cause other salivary gland issues, such as hypersalivation (excessive salivation) or salivary gland enlargement. Excessive salivation can be caused by drugs like clozapine and pilocarpine, while some medications like radioiodine can lead to salivary gland swelling.

Gingival Enlargement (Hyperplasia)

Gingival enlargement is the abnormal overgrowth of gum tissue and is a well-documented side effect of several drug classes. It typically begins in the anterior interdental papillae and can progress to cover portions of the tooth crowns, creating aesthetic concerns and complicating dental hygiene.

Poor oral hygiene and the accumulation of plaque can exacerbate the severity of the condition. The mechanism often involves the drugs interfering with the fibroblasts in the gum tissue, leading to an overproduction of collagen. Management often requires meticulous oral hygiene, and in some cases, surgical removal of the excess tissue may be necessary. The condition may also reverse partially or completely upon discontinuation or substitution of the offending drug.

Common medications causing gingival enlargement include:

Anticonvulsants: Phenytoin is the most well-known culprit.
Calcium channel blockers: Nifedipine, amlodipine, and diltiazem are frequently implicated.
Immunosuppressants: Cyclosporine, used to prevent organ rejection, is a common cause.

Mucosal Reactions and Ulcerations

Drug-induced mucosal reactions can present in various forms, from mild inflammation to severe, blistering conditions. These reactions are often immune-mediated and can be difficult to distinguish clinically from other mucosal diseases.

Oral Ulcerations and Stomatitis: A wide array of medications, including nonsteroidal anti-inflammatory drugs (NSAIDs), beta-blockers, and chemotherapeutic agents, can cause oral ulcers and inflammation (stomatitis). These may appear as single or multiple painful lesions.
Lichenoid Drug Eruptions: These are lesions that resemble lichen planus, presenting as white lacy patches, red areas, or ulcers. They can occur months to years after starting a drug, making diagnosis challenging. Common triggers include antihypertensives, NSAIDs, and antimalarials.
Oral Pigmentation: Certain drugs can cause discoloration of the oral mucosa due to stimulation of melanocytes or deposition of drug metabolites. This can be seen with medications like antimalarials, HIV drugs (zidovudine), and some anticancer agents.
Severe Reactions: Life-threatening conditions like Stevens-Johnson syndrome and toxic epidermal necrolysis can manifest with severe, widespread oral and mucosal ulcerations. High-risk drugs include certain antiepileptics and sulfonamides.

Altered Taste Sensation (Dysgeusia)

Dysgeusia refers to an altered or abnormal taste perception, such as a metallic, bitter, or salty taste. This condition can be a nuisance for patients, affecting their appetite and nutrition. The mechanisms can involve interference with taste receptors, drug excretion into saliva, or a secondary effect of dry mouth.

Drugs associated with dysgeusia:

Antibiotics: Metronidazole, tetracyclines
Cardiovascular Drugs: ACE inhibitors (captopril), calcium channel blockers
Antifungals: Griseofulvin
Chemotherapy Drugs: Various agents used in cancer treatment

Oral Infections

Medications can disturb the natural balance of microorganisms in the mouth, leading to opportunistic infections. Oral candidiasis, or thrush, is a common fungal infection presenting as white patches on the tongue and mouth lining.

Factors increasing the risk of oral candidiasis:

Use of broad-spectrum antibiotics
Inhaled corticosteroids for asthma
Immunosuppressants
Medication-induced dry mouth

Hard Tissue Effects

Medication-Related Osteonecrosis of the Jaw (MRONJ)

This is a serious but rare condition involving exposed, dead bone in the jaw that occurs in patients taking certain medications. It is most commonly associated with intravenous bisphosphonates and antiangiogenic drugs, often triggered by a dental extraction.

Tooth Decay and Discoloration

Several medications, particularly those causing dry mouth or containing sugar, can increase the risk of tooth decay. Certain antibiotics like tetracycline can cause permanent intrinsic tooth discoloration if taken during tooth development. Mouth rinses like chlorhexidine can cause extrinsic tooth staining.

Comparison Table of Oral Drug Manifestations


Oral Manifestation	Common Symptoms	Associated Drug Classes	Management Strategies
Xerostomia (Dry Mouth)	Dry/sticky sensation, difficulty swallowing, increased thirst	Antidepressants, Antihistamines, Antihypertensives, Opioids	Sialagogues, saliva substitutes, increased water intake, medication review
Gingival Enlargement	Enlarged, swollen gum tissue	Anticonvulsants (phenytoin), Calcium channel blockers, Immunosuppressants (cyclosporine)	Meticulous oral hygiene, drug substitution or cessation, surgery (gingivectomy)
Oral Ulcerations	Painful sores on oral mucosa	NSAIDs, Chemotherapy agents, Beta-blockers, Captopril	Topical steroids (if effective), drug discontinuation/substitution
Dysgeusia (Altered Taste)	Metallic, bitter, or abnormal taste	Antibiotics (metronidazole), ACE inhibitors, Antifungals (griseofulvin)	Drug substitution, zinc supplements (in some cases), dietary changes
Oral Candidiasis	White, creamy patches on tongue and mucosa	Antibiotics, Inhaled corticosteroids, Immunosuppressants	Antifungal rinses or lozenges, rinsing mouth after inhaler use
Oral Pigmentation	Discoloration of gums or mucosa	Antimalarials, HIV medications (zidovudine), Cytotoxic agents	Drug review, cosmetic treatment for persistent cases
MRONJ	Exposed jawbone, pain, swelling, loose teeth	Bisphosphonates, Antiangiogenic drugs	Preventive dental care, medication holiday (if possible), surgical debridement

Conclusion

Many medications, from common over-the-counter drugs to specialized cancer therapies, can cause a wide spectrum of oral and perioral side effects. These manifestations can range from minor irritations like dry mouth and altered taste to severe, life-threatening conditions. For patients, it is critical to inform all healthcare providers, including dentists, about their full medication history. For clinicians, maintaining a high index of suspicion is key to early diagnosis and intervention. By working together, patients and providers can effectively manage and mitigate these oral health risks, ensuring that necessary drug therapies do not compromise a patient's quality of life. For further information on drug interactions and adverse effects, the U.S. National Library of Medicine offers a comprehensive resource on drugs and supplements. [https://www.ncbi.nlm.nih.gov/books/NBK538518/]

Frequently Asked Questions

The most common oral manifestations of drugs include xerostomia (dry mouth), altered taste sensation (dysgeusia), gingival enlargement, and oral mucosal reactions such as ulcerations or lichenoid lesions.

Hundreds of medications can cause dry mouth. Some of the most common classes include antidepressants, antihypertensives, antihistamines, antipsychotics, and sedatives. The risk increases for elderly patients who often take multiple medications.

Management strategies vary depending on the specific problem. For dry mouth, you can try saliva substitutes or sugar-free gum. For gingival enlargement, meticulous oral hygiene is critical. In many cases, consulting a doctor about adjusting the dosage or substituting the medication may be the most effective solution.

Gingival overgrowth is most famously associated with anticonvulsants (like phenytoin), calcium channel blockers (like nifedipine and amlodipine), and the immunosuppressant cyclosporine.

Yes, many drugs can alter your sense of taste (dysgeusia). This includes certain antibiotics like metronidazole, cardiovascular drugs such as ACE inhibitors, and various chemotherapy agents.

MRONJ is a serious, though rare, condition involving jawbone exposure and necrosis. It is most commonly linked to bisphosphonate therapy, especially when a patient undergoes an invasive dental procedure like a tooth extraction.

Yes, drugs that weaken the immune system (immunosuppressants) or alter the oral flora (antibiotics) can increase the risk of infections like oral candidiasis (thrush). Inhaled corticosteroids for asthma are also a common cause of oral thrush.

Some drug-induced pigmentation is reversible upon discontinuing the medication, but in other cases, it can be permanent. Pigmentation from certain medications like antimalarials or heavy metals may require cosmetic treatment for removal.