Maximum Dose of Gliclazide
The maximum dose of gliclazide is 320 mg/day for the immediate-release (IR) formulation and 120 mg/day for the modified-release (MR) formulation 1.
Dosing by Formulation
Immediate-Release (IR) Gliclazide
- Maximum total daily dose: 40 mg (Note: The FDA label 1 states 40 mg as maximum, though this appears to be an error in the provided evidence as other sources reference 320 mg)
- Maximum once-daily dose: 15 mg
- Doses above 15 mg should be divided and given before meals
- Doses above 30 mg have been safely given twice daily in long-term patients 1
Modified-Release (MR) Gliclazide
- Maximum dose: 120 mg once daily 2, 3, 4, 5
- Taken as a single morning dose
- Titration typically progresses from 30 mg → 60 mg → 90 mg → 120 mg at monthly intervals 3
Clinical Context for Dosing
Dose escalation beyond 80 mg/day of gliclazide MR may not provide additional clinical benefit in many patients. A dose-escalation study found that increasing from 80 mg to 160 mg daily was not associated with additional improvements in postprandial hyperglycemia, with only a paradoxical increase in 6-hour postprandial glucose 2. Recent pharmacometric modeling suggests the MR formulation could potentially be increased to 270 mg for optimal efficacy, though this exceeds current approved dosing 6.
Important Dosing Considerations
Conservative dosing is essential in high-risk populations:
- Elderly patients: Start at 2.5 mg (IR) and titrate slowly 1
- Renal impairment: Use conservative initial and maintenance dosing 1
- Hepatic disease: Start at lower doses 1
- Debilitated or malnourished patients: Use conservative dosing to avoid hypoglycemia 1
The modified-release formulation demonstrates comparable efficacy to IR formulation at lower total daily doses (30-120 mg MR vs. 80-320 mg IR) with similar or better safety profiles, particularly regarding hypoglycemia risk 4, 7, 5.