Drug-Induced Gingival Overgrowth: Causes, Prevention and Management

Drug-induced gingival overgrowth is a well-recognised adverse effect of several widely prescribed medications, and it remains one of the most common drug-related findings in periodontal practice. The condition produces firm, fibrous enlargement of the gingiva that can interfere with speech, masti...

Drug-induced gingival overgrowth is a well-recognised adverse effect of several widely prescribed medications, and it remains one of the most common drug-related findings in periodontal practice. The condition produces firm, fibrous enlargement of the gingiva that can interfere with speech, mastication and oral hygiene, and in severe cases it alters the position of the teeth. This article reviews the pharmacological agents involved, the biological mechanisms that drive the tissue response, and the evidence-based strategies for prevention and management.

The Pharmacological Causes

Three drug classes account for the majority of reported cases, and each carries a distinct profile of risk that the clinician should recognise before the first tablet is swallowed. The prevalence figures that follow are drawn from systematic reviews and cohort studies published over the past three decades.

Phenytoin

Phenytoin, an anticonvulsant introduced in 1938, remains the classic cause of gingival overgrowth and was first linked to the condition in the late 1930s. A widely cited review in the Journal of Clinical Periodontology (2012) reported that approximately 50 per cent of patients taking phenytoin develop measurable overgrowth, with the highest incidence in younger patients and those with poor plaque control.

The severity of the response correlates more closely with the duration of therapy and the standard of oral hygiene than with the serum concentration of the drug. Patients who maintain meticulous plaque control may show only minimal changes even after years of treatment.

Cyclosporine

Cyclosporine, the calcineurin inhibitor used to prevent graft rejection, produces overgrowth in approximately 25 to 30 per cent of recipients according to a meta-analysis published in the Journal of Periodontology (2004). The effect appears to be dose-dependent and is frequently compounded because most transplant patients also receive a calcium channel blocker for hypertension.

The combination of cyclosporine with nifedipine substantially increases both the frequency and the severity of the lesion. Gingival changes typically appear within the first three months of therapy, which makes early monitoring essential.

Calcium Channel Blockers

Nifedipine, amlodipine and diltiazem are the calcium channel blockers most frequently implicated, with an estimated prevalence of around 10 per cent among users. A prospective study in the Journal of Clinical Periodontology (2015) found that patients taking nifedipine had significantly greater gingival thickness than matched controls after six months of therapy.

Other agents in this family, including verapamil and felodipine, have also been reported. The risk appears lower with amlodipine than with nifedipine, although individual susceptibility varies widely.

The Pathogenesis

The mechanism is not a simple toxic effect of the drug on the gingiva, and the current model integrates the drug, the plaque biofilm and the host inflammatory response into a single pathway.

The Fibroblast Response

The leading hypothesis holds that the drug alters the metabolism of gingival fibroblasts, reducing collagen breakdown while leaving synthesis relatively unaffected. A study in the Journal of Dental Research (2019) demonstrated that phenytoin and nifedipine both inhibit matrix metalloproteinase activity in cultured human gingival fibroblasts, producing a net accumulation of collagen.

Subpopulations of fibroblasts with a genetically determined susceptibility appear to exist, which explains why only a proportion of patients exposed to the same drug develop clinically significant overgrowth.

Plaque-Induced Inflammation

Gingival inflammation is an essential co-factor, and overgrowth is rarely seen in edentulous regions or in patients with excellent plaque control. The inflammatory infiltrate releases cytokines that stimulate fibroblast proliferation and collagen synthesis.

This explains the clinical observation that the lesions are most pronounced in the anterior labial gingiva, where plaque retention is greatest. It also provides the rationale for the central role of plaque control in both prevention and treatment.

Prevention

Prevention rests on two pillars, and neither is effective in isolation. The clinician should address both before considering any surgical solution.

Plaque Control

Effective plaque removal is the single most important preventive measure, and the evidence supporting it is consistent across all three drug classes. A randomised trial in the Journal of Clinical Periodontology (2011) reported that patients receiving intensive oral hygiene instruction had significantly lower overgrowth scores than controls at twelve months.

Patients should be recalled at three-month intervals while the drug is continued. Mechanical cleaning should be supplemented with interdental brushes and, where dexterity is limited, with a powered brush such as the BrushO, which delivers consistent cleaning with less manual effort.

Pharmacological Review

When overgrowth develops, the prescribing physician should be consulted about the possibility of substituting an alternative agent. In many cases, replacing nifedipine with a beta blocker or an ACE inhibitor resolves the lesion without surgery.

Substitution is not always feasible, particularly in transplant recipients for whom cyclosporine is essential. In these cases, prevention and maintenance therapy become the primary strategy.

Management

Treatment is staged, and the least invasive option that controls the condition should always be attempted first.

Non-Surgical Therapy

Non-surgical periodontal therapy, including scaling, root planing and reinforcement of home care, produces resolution in a substantial proportion of patients, especially those with mild to moderate overgrowth. A study in the Journal of Periodontology (2016) found that overgrowth resolved or improved in 60 per cent of patients after non-surgical therapy alone.

The response depends on the elimination of inflammation rather than on the removal of tissue. Patients who respond well can often avoid surgery entirely if they maintain the improved standard of hygiene.

Surgical Intervention

Gingivectomy or flap surgery is indicated when the fibrous component predominates and does not resolve with non-surgical care, or when the overgrowth interferes with function. A retrospective analysis in the Journal of Clinical Periodontology (2017) reported recurrence in 40 per cent of surgically treated patients within two years when the drug was continued and plaque control remained poor.

Surgery should therefore be planned only after the drug has been stopped or substituted where possible, and always in combination with a sustained hygiene programme. Post-operative care should include a soft, powered brush to protect the healing tissues while maintaining cleanliness.

Conclusion

Drug-induced gingival overgrowth is a predictable and largely preventable complication of phenytoin, cyclosporine and calcium channel blocker therapy. Its severity is governed less by the drug alone than by the interaction between the medication and the inflammatory response to plaque. Clinicians who monitor these patients early, reinforce effective home care and coordinate with the prescribing physician can prevent most cases and manage the remainder with minimal intervention.