Short answer: Glimepiride (Amaryl) and glipizide extended-release (Glucotrol XL) are sulfonylurea tablets taken once a day with breakfast for type 2 diabetes.12 Glimepiride starts at 1 or 2 mg, up to 8 mg; Glucotrol XL starts at 5 mg, up to 20 mg. Low blood sugar is the key risk of both. Neither label reports a trial against the other.
| Glimepiride (Amaryl) | Glipizide XL (Glucotrol XL) | |
|---|---|---|
| Tablets | 1, 2 or 4 mg1 | 2.5, 5 or 10 mg extended-release, swallowed whole2 |
| Start | 1 or 2 mg once a day with breakfast or first main meal; 1 mg if at higher risk of lows1 | 5 mg once a day with breakfast or first main meal; 2.5 mg if at higher risk of lows2 |
| Maximum | 8 mg once a day1 | 20 mg once a day2 |
| Low blood sugar in label trials | Possible lows 19.7% vs 3.2% on placebo (22-week trial)1 | 3.4% of 580 people; 2.6% stopped because of it2 |
| Other side effects | Headache 8.2% vs 7.8%; dizziness 5% vs 2.4%1 | Dizziness 6.8% vs 5.8%; diarrhea 5.4% vs 0%2 |
| Boxed warning | None1 | None2 |
Both are approved with diet and exercise for adults with type 2 diabetes and are not for type 1 or diabetic ketoacidosis.12 The doses are on different scales: glimepiride goes up by 1 or 2 mg, no more often than every 1 to 2 weeks, to 8 mg; Glucotrol XL is adjusted by blood sugar up to 20 mg.12
The low blood sugar numbers were counted differently (possible lows in one 22-week trial vs all trial participants), so they cannot be lined up. These numbers come from separate trials with different people, lengths and methods, so they are not a head-to-head comparison. The glimepiride label also notes weight gain.1
Your prescriber picks the drug and dose. More detail: glimepiride side effects, Glucotrol XL side effects, and the glimepiride and Glucotrol XL dosing schedules.