What is the appropriate dosage and administration of atropine (antimuscarinic) ophthalmic for off-label use in treating hypersalivation in a 73-year-old patient?

Atropine Ophthalmic Solution for Hypersalivation in a 73-Year-Old Patient

Sublingual atropine ophthalmic solution at a dose of 1-2 drops (0.5-1.0 mg) administered 2-3 times daily is effective for managing hypersalivation in elderly patients, with careful monitoring for anticholinergic side effects. 1, 2

Dosage and Administration

• Start with 1 drop (approximately 0.5 mg) of 1% atropine ophthalmic solution administered sublingually 2-3 times daily, increasing to 2 drops if needed based on response 1, 2
• Administer by placing the drops directly under the tongue and instructing the patient to avoid swallowing immediately 2
• The bioavailability of 1.0 mg sublingual atropine is approximately 60% compared to intravenous administration, making it an effective route for systemic absorption 3
• Objective measurement shows significant reduction in saliva secretion within 2 hours after administration, with effects lasting several hours 1, 4

Efficacy and Evidence

• Sublingual atropine has demonstrated significant reduction in unstimulated saliva secretion compared to placebo (mean difference = -57.21%, p = 0.02) 1
• Clinical studies have shown that 21 out of 24 patients experienced beneficial effects on hypersalivation with sublingually administered atropine eye drops 2
• Objective measurements using sialometry have confirmed reduction in salivary flow rates from 0.60 g/min to 0.23 g/min after sublingual atropine administration 4

Monitoring and Safety Considerations

• Carefully monitor for anticholinergic side effects, particularly in elderly patients, including:

  • Tachycardia (though paradoxical bradycardia has been reported with doses <0.5 mg) 5, 6
  • Dry mouth (which may actually be beneficial in this context) 1, 2
  • Central nervous system effects including confusion, hallucinations, and delirium, especially in elderly patients 5, 6
  • Urinary retention and constipation 5
  • Visual disturbances 5

• Start with lower doses in elderly patients due to increased sensitivity to anticholinergic effects 6

• Consider using punctal occlusion to reduce systemic absorption if administering as eye drops rather than sublingually 5

Special Considerations for Elderly Patients

• In patients over 70 years old, anticholinergic medications carry increased risk of cognitive impairment and falls 6
• Perform baseline assessment of cognitive function before initiating therapy 6
• Avoid use in patients with narrow-angle glaucoma, prostatic hypertrophy, or significant cardiac disease 6
• Consider potential drug interactions with other medications that have anticholinergic properties 6

Alternative Formulations

• A mucoadhesive topical oral gel formulation of atropine (0.01% w/w) is being developed as an alternative to eye drops and has shown a favorable pharmacokinetic profile in clinical studies 7
• This formulation may provide more precise dosing and potentially fewer systemic side effects compared to eye drops 7

Follow-up and Adjustment

• Assess response after 1 week of therapy 1, 2
• If inadequate response, increase to 2 drops per administration 2
• If excessive anticholinergic effects occur, reduce to 1 drop or decrease frequency 2
• Consider discontinuation if significant adverse effects develop 4