Diabetes Medications 💉
Reference guide for diabetes medications. Drug table, dosing, and prescribing for type 2 diabetes and insulin therapy.
💡 Overview
- First-line for type 2 diabetes: metformin (if no contraindications).
- Add second-line agent based on comorbidities: SGLT2i/GLP-1 for cardio/renal/weight; DPP-4i if weight-neutral preferred; sulfonylurea if cost/simplicity.
- Insulin when oral agents insufficient or in type 1 diabetes. Sliding scale only as per local protocol; prefer basal–bolus where appropriate.
📋 Ward considerations
- Hold metformin in acute illness, before contrast, and if eGFR drops (risk of lactic acidosis).
- Hold SGLT2i in acute illness, perioperatively, and when fasting (DKA risk).
- Sulfonylureas: hypoglycaemia risk; reduce or hold in poor intake or renal impairment.
- Review insulin doses when diet poor, on steroids, or if renal/liver function changes.
Diabetes Medications
Reference table for diabetes management
| Drug | Dose | Frequency | Class | Notes |
|---|---|---|---|---|
| Biguanides | ||||
| Metformin (Glucophage) | 500 mg – 1 g | BD (with meals) | Biguanide | First-line. Avoid in eGFR <30; caution 30–45. Risk of lactic acidosis in acute illness. |
| Sulfonylureas | ||||
| Gliclazide (Diamicron) | 40–320 mg | OD or BD | Sulfonylurea | Hypoglycaemia risk. Caution in elderly and renal impairment. |
| Glimepiride (Amaryl) | 1–4 mg | OD | Sulfonylurea | Longer duration. Avoid in severe renal impairment. |
| DPP-4 inhibitors | ||||
| Sitagliptin (Januvia) | 100 mg (50 mg if eGFR 30–50) | OD | DPP-4i | Weight-neutral. Dose-reduce in renal impairment. |
| Linagliptin (Trajenta) | 5 mg | OD | DPP-4i | No dose adjustment in renal impairment. |
| Vildagliptin (Galvus) | 50 mg BD (50 mg OD if with metformin) | BD or OD | DPP-4i | Caution in heart failure. Dose-reduce if eGFR <50. |
| SGLT2 inhibitors | ||||
| Empagliflozin (Jardiance) | 10–25 mg | OD | SGLT2i | Cardio/renal benefits. Avoid if eGFR <20. DKA risk if unwell. |
| Dapagliflozin (Forxiga) | 10 mg | OD | SGLT2i | Stop in acute illness (sickness, surgery). Genital infections. |
| Canagliflozin (Invokana) | 100–300 mg | OD | SGLT2i | Similar to above. 300 mg only if eGFR ≥60. |
| GLP-1 receptor agonists | ||||
| Dulaglutide (Trulicity) | 0.75–1.5 mg | Once weekly | GLP-1 RA | SC injection. Nausea; titrate. Cardio benefits. |
| Semaglutide (Ozempic) | 0.25–1 mg | Once weekly | GLP-1 RA | SC. Avoid in pancreatitis, medullary thyroid Ca. |
| Liraglutide (Victoza) | 0.6–1.8 mg | OD | GLP-1 RA | Daily SC. Similar cautions. |
| Tirzepatide (Mounjaro) | 2.5–15 mg | Once weekly | GIP/GLP-1 RA | Dual agonist; SC. Titrate from 2.5 mg. Similar GLP-1 cautions. |
| Insulin (ward common) | ||||
| Short-acting (Actrapid, Humalog, Novorapid, Apidra) | Variable | With meals or sliding scale | Short-acting | Give with meals. Sliding scale for inpatients if prescribed. |
| Long-acting (Lantus, Levemir, Abasaglar, Toujeo, Tresiba) | Variable | OD or BD | Long-acting | Basal insulin. Usually once daily at same time. |
| Mixed (Humalog Mix 25, NovoMix 30, Humulin M3) | Variable | BD with meals | Mixed | Pre-mixed; less flexible. Check local protocols. |
| Other | ||||
| Pioglitazone (Actos) | 15–45 mg | OD | TZD | Avoid in heart failure, bladder Ca. Fracture risk. |
| Acarbose (Glucobay) | 50–100 mg | TDS with first bite | Alpha-glucosidase inhibitor | GI side effects. Rarely used alone. |
Biguanides
Metformin (Glucophage)
BiguanideDose:500 mg – 1 g
Frequency:BD (with meals)
Notes: First-line. Avoid in eGFR <30; caution 30–45. Risk of lactic acidosis in acute illness.
Sulfonylureas
Gliclazide (Diamicron)
SulfonylureaDose:40–320 mg
Frequency:OD or BD
Notes: Hypoglycaemia risk. Caution in elderly and renal impairment.
Glimepiride (Amaryl)
SulfonylureaDose:1–4 mg
Frequency:OD
Notes: Longer duration. Avoid in severe renal impairment.
DPP-4 inhibitors
Sitagliptin (Januvia)
DPP-4iDose:100 mg (50 mg if eGFR 30–50)
Frequency:OD
Notes: Weight-neutral. Dose-reduce in renal impairment.
Linagliptin (Trajenta)
DPP-4iDose:5 mg
Frequency:OD
Notes: No dose adjustment in renal impairment.
Vildagliptin (Galvus)
DPP-4iDose:50 mg BD (50 mg OD if with metformin)
Frequency:BD or OD
Notes: Caution in heart failure. Dose-reduce if eGFR <50.
SGLT2 inhibitors
Empagliflozin (Jardiance)
SGLT2iDose:10–25 mg
Frequency:OD
Notes: Cardio/renal benefits. Avoid if eGFR <20. DKA risk if unwell.
Dapagliflozin (Forxiga)
SGLT2iDose:10 mg
Frequency:OD
Notes: Stop in acute illness (sickness, surgery). Genital infections.
Canagliflozin (Invokana)
SGLT2iDose:100–300 mg
Frequency:OD
Notes: Similar to above. 300 mg only if eGFR ≥60.
GLP-1 receptor agonists
Dulaglutide (Trulicity)
GLP-1 RADose:0.75–1.5 mg
Frequency:Once weekly
Notes: SC injection. Nausea; titrate. Cardio benefits.
Semaglutide (Ozempic)
GLP-1 RADose:0.25–1 mg
Frequency:Once weekly
Notes: SC. Avoid in pancreatitis, medullary thyroid Ca.
Liraglutide (Victoza)
GLP-1 RADose:0.6–1.8 mg
Frequency:OD
Notes: Daily SC. Similar cautions.
Tirzepatide (Mounjaro)
GIP/GLP-1 RADose:2.5–15 mg
Frequency:Once weekly
Notes: Dual agonist; SC. Titrate from 2.5 mg. Similar GLP-1 cautions.
Insulin (ward common)
Short-acting (Actrapid, Humalog, Novorapid, Apidra)
Short-actingDose:Variable
Frequency:With meals or sliding scale
Notes: Give with meals. Sliding scale for inpatients if prescribed.
Long-acting (Lantus, Levemir, Abasaglar, Toujeo, Tresiba)
Long-actingDose:Variable
Frequency:OD or BD
Notes: Basal insulin. Usually once daily at same time.
Mixed (Humalog Mix 25, NovoMix 30, Humulin M3)
MixedDose:Variable
Frequency:BD with meals
Notes: Pre-mixed; less flexible. Check local protocols.
Other
Pioglitazone (Actos)
TZDDose:15–45 mg
Frequency:OD
Notes: Avoid in heart failure, bladder Ca. Fracture risk.
Acarbose (Glucobay)
Alpha-glucosidase inhibitorDose:50–100 mg
Frequency:TDS with first bite
Notes: GI side effects. Rarely used alone.
SmPCs (medicines.ie / HPRA)
Metformin (Glucophage 850 mg)Gliclazide (Diamicron MR 60 mg)Glimepiride (Amaryl, HPRA)Sitagliptin (Januvia)Linagliptin (Trajenta 5 mg)Vildagliptin (Galvus 50 mg)Empagliflozin (Jardiance)Dapagliflozin (Forxiga)Canagliflozin (Invokana)Dulaglutide (Trulicity)Semaglutide (Ozempic 1 mg)Liraglutide (Victoza)Tirzepatide (Mounjaro)Insulin short-acting (Actrapid)Insulin long-acting (Lantus)Insulin mixed (NovoMix 30)Pioglitazone (Actos, EMA)Acarbose (Glucobay 100 mg, HPRA)
Hypoglycaemia management (PRN)
Treatment options for ward hypoglycaemia. Use as required.
| Scenario | Treatment | Dose | Notes |
|---|---|---|---|
| Conscious, able to swallow | Fast-acting oral CHO | 15–20 g: 4–5 dextrose tablets, 150–200 mL juice, or 1–2 tubes Glucogel/Hypostop | 15–15 rule: recheck BM in 15 min; repeat if <4. Then snack/meal. |
| Unconscious or unable to swallow | Dextrose 20% IV | 50–100 mL (or 10% 100–200 mL) | Flush line; avoid extravasation. Recheck BM in 10–15 min. |
| Unconscious, no IV access | Glucagon | 1 mg IM (0.5 mg if <25 kg) | Onset 5–15 min. Give oral CHO when rousable. Less effective if glycogen depleted. |
| Recovery | Longer-acting CHO + meal | Snack or meal once BM stable | Document; review insulin/meds. Avoid overtreating. |
Conscious, able to swallow
Treatment: Fast-acting oral CHO
Dose: 15–20 g: 4–5 dextrose tablets, 150–200 mL juice, or 1–2 tubes Glucogel/Hypostop
Notes: 15–15 rule: recheck BM in 15 min; repeat if <4. Then snack/meal.
Unconscious or unable to swallow
Treatment: Dextrose 20% IV
Dose: 50–100 mL (or 10% 100–200 mL)
Notes: Flush line; avoid extravasation. Recheck BM in 10–15 min.
Unconscious, no IV access
Treatment: Glucagon
Dose: 1 mg IM (0.5 mg if <25 kg)
Notes: Onset 5–15 min. Give oral CHO when rousable. Less effective if glycogen depleted.
Recovery
Treatment: Longer-acting CHO + meal
Dose: Snack or meal once BM stable
Notes: Document; review insulin/meds. Avoid overtreating.
Educational reference only. Medical disclaimer