Pilocarpine for Medication-induced Dry Mouth and Dry Eyes: A Review of Clinical Effectiveness, Cost-Effectiveness, and Guidelines

Xerostomia is defined as dry mouth due to reduced salivary flow.¹ As a result of this, patients may have decreased efficiency in chewing and swallowing and an increased risk of dental disease, such as dental caries (i.e., dental decay).¹ Xerostomia may be caused by medications, chronic disease, and radiotherapy.² The prevalence of xerostomia in patients taking medications is higher than in those not taking medications (28% versus 7.5%, respectively).³ In particular, xerostomia is a potential side effect of psychoactive medications including antidepressants and antipsychotics.² For example, patients taking tricyclic antidepressants had a 58% reduction in salivary flow rate compared to patients not taking tricyclic antidepressants, while those taking selective serotonin re-uptake inhibitors (SSRIs) had a 32% reduction compared to patients not taking SSRIs.⁴ Treatment for xerostomia includes but is not limited to mouth wash, artificial saliva, moisturizer, and cholinergic drugs (e.g., pilocarpine and cevimeline).⁵ Dry eyes is a condition in which the tears are inadequate to lubricate the eyes, which may lead to symptoms such as scratching, stinging or burning sensation, light sensitivity, and blurred vision.⁶ In 2019, it was estimated that 21.3% of Canadian adults may have dry eye disease (DED), which includes medication-induced dry eyes.⁷ Oral psychoactive medications can also contribute to dry eye disease.⁸ Treatment for dry eyes depends on the cause of the condition and includes punctal plugs for the tear draining ducts, anti-inflammatory drugs, artificial tears, and cholinergic drugs (e.g., pilocarpine and cevimeline).⁶ The purpose of this report is to examine recent literature regarding clinical effectiveness, cost-effectiveness and evidence-based guidelines of pilocarpine for the treatment of psychoactive medication-induced dry mouth or dry eyes.