Table 2.
| Class | Dosing | Precaution |
|---|---|---|
| Sulfonylureas | General: hypoglycemia | |
| Glimepiride | Starting: 1–2 mg once daily with first main meal Maintenance: 1–4 mg once daily Maximum: 8 mg once daily |
In renally impaired patients (creatinine clearance < 22 mL/min), a glimepiride dose of 1.0 mg may be sufficient |
| Glipizide | Starting: 5 mg once daily with breakfast Maintenance: 5–10 mg once daily Maximum: 20 mg once daily |
May need to reduce glipizide dose in patients with impaired renal or hepatic function |
| Glyburide | Starting: 2.5–5.0 mg once daily with first meal Maintenance: 1.25–20.0 mg, once daily or divided twice daily Maximum: 20 mg |
Initiate dose at 1.25 mg/day in patients with impaired renal or hepatic function |
| Chlorpropamide | Starting: 250 mg once daily Maintenance: 250 mg once daily (100–125 mg with less severe hyperglycemia) Maximum: 500 mg, maintenance doses > 750 mg should be avoided |
Certain reactions associated with idiosyncrasy or hypersensitivity have occurred; these include jaundice, skin eruptions less frequently progressing to erythema multiforme, and exfoliative dermatitis. Reactions are mild, occur usually within 6 wk of initial therapy and resolve with drug discontinuation |
| Meglitinides | General: Titrate upward with care in patients with impaired hepatic function | |
| Repaglinide | Starting: A1C < 8.0%, 0.5 mg with each meal; A1C ≥ 8.0%, 1–2 mg dose Maintenance: 0.5–4.0 mg with meals Maximum: 16 mg total once daily |
Initial repaglinide dose should be 0.5 mg with each meal and carefully titrated upward in patients with severe renal impairment |
| Nateglinide | Starting/maintenance: 120 mg 3 times daily, before meals; 60-mg dose if near A1C goal | (See general precautions for meglitinides) |
| Thiazolidinediones | General: Weight gain and edema are primary side effects | |
| Pioglitazone | Starting: 15 mg or 30 mg once daily Maintenance: 15–45 mg once daily Maximum: 45 mg once daily |
Use with caution in patients with existing edema |
| Avoid use in patients at risk for heart failure | ||
| Rosiglitazone | Starting: 4 mg once daily or divided twice daily Maximum: 8 mg once daily or divided twice daily |
Therapy should not be initiated in patients with serum transaminase levels 2.5–3.0 times the upper limit of normal and/or evidence of liver disease |
| Monitor liver function tests periodically | ||
| Biguanides (metformin) | General: High levels can cause lactic acidosis | |
|
Immediate-release formula Starting: 850 mg once daily or 500 mg twice daily; titrate increases at 500 mg/wk or 850 mg every 2 wks Maintenance: 1500–2000 mg daily in divided doses, with meals Maximum: 2550 mg/day Extended-release formula Starting: 500 mg once daily with evening meal; titrate increases at 500 mg/wk Maximum: 2000 mg once daily or divided twice daily (if higher doses are required, use immediate-release formula) Liquid formula Starting: 500 mg twice daily or 850 mg once daily with meals; increase dose 500 mg/wk or 850 mg/2 wk Maintenance: 1500 mg-2000 mg once daily divided among meals Maximum: 2550 mg divided into 3 doses |
Contraindicated when serum creatinine levels exceed 1.4 (women) to 1.5 (men) mg/dL | |
| Other contraindications: congestive heart failure, significant liver disease, or any condition predisposing hypoperfusion | ||
| When first taken, may cause nausea, diarrhea; liquid form may aid gradual titration | ||
| Alpha-glucosidase inhibitors | General: Side effects include intestinal gas, abdominal cramps, and diarrhea; symptoms usually subside with time | |
| Acarbose | Starting: 25 mg 3 times daily with first bite of each meal; to minimize side effects, titrate from 25 mg once daily Maintenance: 25–50 mg 3 times daily Maximum: ≤ 60 kg, 50 mg 3 times daily; > 60 kg, 100 mg 3 times daily |
Serum transaminase may be elevated with acarbose; should be checked every 3 months during the first year of therapy; consider dose reduction or discontinuation if elevated |
| Acarbose is not recommended for patients with renal impairment until more clinical trial data are available for this population | ||
| Miglitol | Starting: 25 mg 3 times daily with first bite of each meal to minimize side effects; after 4–8 weeks, titrate gradually to 50 mg 3 times daily Maintenance: 50 mg 3 times daily Maximum: 100 mg 3 times daily |
Miglitol may accumulate in patients with renal impairment |