What medications can cause dry mouth?

Medications That Cause Dry Mouth

Anticholinergic medications are the most common cause of medication-induced dry mouth, with numerous drug classes having this side effect due to their inhibition of muscarinic receptors in salivary glands. 1

Common Medication Classes Associated with Dry Mouth

1. Anticholinergic Medications

• First-generation antihistamines

  • Dexbrompheniramine, azatadine 2
  • These older antihistamines cause dry mouth through their anticholinergic properties, unlike newer generation antihistamines 2

• Antipsychotics

  • Particularly those with anticholinergic properties
  • Atypical antipsychotics (though some like clozapine and olanzapine may paradoxically cause hypersalivation in some patients) 3

• Antidepressants

  • Tricyclic antidepressants 2
  • Selective serotonin reuptake inhibitors (SSRIs)
  • Medications affecting serotonin and noradrenaline uptake 1

• Urological medications

  • Anticholinergics used for overactive bladder

2. Other Common Medication Classes

• Muscle relaxants

  • Cyclobenzaprine (has anticholinergic activity similar to tricyclic antidepressants) 2
  • Tizanidine 2
  • Carisoprodol 2

• Antihypertensives

  • Beta-blockers (atenolol, metoprolol, propranolol) 2
  • Calcium channel blockers 2
  • Diuretics 2

• Opioids 2

  • Codeine and other opioid analgesics

• Centrally acting medications

  • Clonidine 2

• Other medications

  • Atropine and other muscarinic antagonists (most potent for causing dry mouth) 4
  • Scopolamine 2
  • Appetite suppressants 1
  • Protease inhibitors 1
  • Cytokines 1

Mechanism of Dry Mouth

Medications cause dry mouth primarily through:

1. Anticholinergic activity: Blocking M3 muscarinic receptors in salivary glands, interrupting neural stimulation of saliva secretion 5, 1

2. Sympathomimetic effects: Some medications with adrenergic activity can reduce salivary flow

3. Polypharmacy effect: Multiple medications with even mild anticholinergic properties can create a cumulative "anticholinergic burden" that significantly reduces salivation 6

Clinical Implications and Management

Consequences of Medication-Induced Dry Mouth

• Dental caries
• Intraoral infections
• Orofacial pain
• Problems with speaking and swallowing
• Diminished oral health-related quality of life 5

Management Approaches

1. Medication adjustment (when possible)

   • Consider alternative medications with less anticholinergic activity
   • Adjust dosing schedule to minimize dry mouth impact 7

2. Supportive measures

   • Good oral hygiene (twice-daily brushing, chlorhexidine or fluoride rinses) 2
   • Dietary modifications (avoid crunchy, spicy, acidic foods and hot beverages) 2
   • Saliva substitutes and mouth rinses 2

3. Pharmacologic interventions

   • Systemic sialagogues (pilocarpine, cevimeline) for severe cases 2
   • Cevimeline has been shown to improve ocular irritation symptoms and aqueous tear production with potentially fewer side effects than pilocarpine 2

Special Considerations

• Elderly patients are particularly susceptible to medication-induced dry mouth due to age-related changes in salivary function and increased likelihood of polypharmacy 7

• Patients with Sjögren's syndrome may experience exacerbated dry mouth symptoms when taking medications with anticholinergic properties 2

• Monitoring anticholinergic burden: Research shows a negative linear relationship between serum anticholinergic activity and unstimulated whole saliva flow - as anticholinergic activity increases, saliva flow decreases predictably 6

Dry mouth is a common but often overlooked medication side effect that can significantly impact quality of life and oral health. When patients present with dry mouth symptoms, a careful medication review should be conducted to identify potential causative agents.