What oral rivastigmine dose (in milligrams per day) is equivalent to a 13.3 mg/24‑hour transdermal patch in an elderly patient with mild‑to‑moderate Alzheimer’s disease or Parkinson’s disease dementia?

Oral Rivastigmine Dose Equivalent to 13.3mg/24hr Patch

The 13.3 mg/24-hour rivastigmine patch is approximately equivalent to 9–12 mg oral rivastigmine per day (administered as 4.5–6 mg twice daily). 1

Dose Conversion Framework

The transdermal patch delivers rivastigmine continuously over 24 hours, avoiding the peak-and-trough plasma concentrations seen with oral dosing. The established equivalencies are:

• 4.6 mg/24-hour patch ≈ 3 mg oral twice daily (6 mg/day total) 1
• 9.5 mg/24-hour patch ≈ 6 mg oral twice daily (12 mg/day total) 1, 2
• 13.3 mg/24-hour patch ≈ higher end of therapeutic range (9–12 mg/day oral) 1, 3

The 13.3 mg/24-hour patch was specifically developed to provide enhanced efficacy beyond the 9.5 mg/24-hour patch for patients requiring higher doses. 3 Clinical trials demonstrated that this higher-dose patch maintains therapeutic benefit while preserving the improved tolerability profile of transdermal delivery compared to oral capsules. 3

Critical Context for Conversion

If converting FROM oral TO patch: The 13.3 mg/24-hour patch is appropriate for patients previously stabilized on oral rivastigmine 9–12 mg/day who require continued high-dose therapy. 3

If converting FROM patch TO oral: A patient on the 13.3 mg/24-hour patch would require oral rivastigmine 4.5–6 mg twice daily (9–12 mg/day total), titrated gradually to minimize cholinergic gastrointestinal adverse events. 4, 5

Important Tolerability Considerations

The transdermal patch provides approximately three times fewer reports of nausea and vomiting compared to oral capsules at equivalent doses. 1, 2 This improved tolerability allows more patients to access higher therapeutic doses without dose-limiting gastrointestinal side effects. 3, 6

When converting to oral dosing, expect:

• Higher incidence of nausea, vomiting, and diarrhea 4, 5
• Need for slower titration intervals (increase by 1.5 mg twice daily every 4 weeks minimum) 4
• Administration with full meals to minimize gastrointestinal effects 4, 5
• Withdrawal rates due to adverse events of 12–29% with oral dosing versus lower rates with patch 1

Practical Dosing Algorithm

For a patient currently on 13.3 mg/24-hour patch requiring conversion to oral:

1. Start oral rivastigmine at 3 mg twice daily (6 mg/day) to re-establish tolerance 4
2. Increase to 4.5 mg twice daily (9 mg/day) after 4 weeks if tolerated 4, 5
3. Consider further increase to 6 mg twice daily (12 mg/day) after another 4 weeks based on tolerability and clinical need 4, 5
4. Always administer with food to reduce gastrointestinal adverse events 4, 5
5. Monitor for cholinergic side effects (nausea, vomiting, diarrhea, weight loss) 4, 1

Common Pitfall to Avoid

Do not abruptly switch from 13.3 mg/24-hour patch to an equivalent oral dose without retitration. 7 Even though the patient has been tolerating high-dose rivastigmine via patch, the different pharmacokinetic profile of oral dosing (with higher peak plasma concentrations) necessitates gradual dose escalation to avoid intolerable gastrointestinal side effects that may lead to treatment discontinuation. 5, 2