| Drug | Brand Name | Action | Dosage | Cautions and Contra Indications | When To Take |
| Biguanide | | | | | |
| Metformin | Glucophage | Decreases Gluconeogenesis. Increases peripheral uptake of glucose | 500 mg. every 8 hours or 850mg every 12 hours maximum 3 g daily in divided doses. | Renal failure, Hepatic impairment, heart failure, trauma, alcohol dependence | with or just after food |
| Glucophage SR | | As above however evidence shows much lower GI side effect profile than regular Metformin. | Once daily after main meal. 500mg tablets. 2g daily maximum dose. | As above | Taken with or after main meal of day |
| Sulphonylureas | | | | | |
| Chlorpropramide (Check availability) | | 36 hrs + auguments insulin secretion | 250 mgs. daily Max. 500 mgs | Encourages weight gain hepatic and renal insufficiency avoid in the elderly | Best before breakfast |
| Glibenclamide | Daonil | 24 - 38 hours as above | 5 mgs - 15 mgs daily | Encourages weight gain hepatic and renal insufficiency avoid in the elderly | Best before breakfast |
| Gliclazide | Diamicron | 24 hours - acts as above | 40mg - 80 mg daily up to 160 mg in a single dose higher doses divided max 320 mgs daily | More suitable for the elderly or those with renal impairment, hepatic insufficiency still a caution | Before breakfast or before meals |
| Gliclazide MR | Diamicron | Modified release | 30mg - 120mg
Gliclazide (30mg approximately equal in effect to 80mg standard gliclazide) | | |
| Glimepiride | Amaryl | 24 hours | 1mg-4mg
Usual max dose 4 mg | Hepatic monitoring | Best before breakfast or first meal |
| Glipizide | Glibenese Minodiab | 24Hrs | 20 mg daily, Minodiab 2.5 – 20mg
Up to 15mg as single dose | Hepatic monitoring | Best before breakfast or first meal |
| Tolbutamide | | Up to 16 hours | 0.5mg - 1.5 mg daily, divided doses max.2 mg daily | Probably the most suitable choice for elderly or renal impairment. | Before breakfast before evening meal |
| Other OHAs | | | | | |
| Acarbose | Glucobay | 6-12 hours Delays digestion and absorption of sugars and starch | 50 mg daily initially - Increase to 50 mg tds Max 200 mg tds | May enhance hypoglycaemic effect of sulphonylureas/insulin, hepatic/renal impairment, irritable bowel syndrome | chew with first mouthful of food or swallow with a little liquid immediately before food |
| Repaglinide | NovoNorm | Rapid onset | 500 microgrammes – 4mg before each main meal (usually tds)
max 16mgs daily | pregnancy, renal/hepatic disorders, Type 1 diabetes, DKA | less than 30 minutes before main meals |
| Nateglinide | Starlix Rapid | 3-4 hrs | 60mg – 180mg
(usually tds) | Type 1 diabetes, Severe Hepatic impairment, Pregnancy, Breast feeding, DKA. | before each meal. |
| Thiazolidinediones | | | | | |
| Pioglitazone/Metformin HCl | Competact | Refer to Actos and Metformin | 15mg/850mg 1 tablet twice daily | Refer to Actos and Metformin | With or just after food |
| Rosiglitazone | Avandia | Increases insulin sensitivity | Recommended 4 mg once daily.
Can increase to 8 mg after 8 weeks, as monotherapy or with metformin | In combination with insulin. Heart failure or history of heart failure. Hepatic impairment. Severe renal impairment | With/without food - same time each day |
| Rosiglitazone/Metformin HCl | Avandamet | Refer to Avandia and Metformin | 1mg/500mg or 2mg/500mg
2mg/1000mg or 4mg/1000mg
1 tablet twice per day | Refer to Avandia and Metformin | With or just after food |
| Pioglitazone | Actos | Increases insulin sensitivity | 15,30 or 45mg mg once daily, Recommended 30 mg once daily, Dose may be increased up to a max 45mg | Heart failure or history of heart failure. Hepatic impairment. Severe renal impairment | with/without food |
| Sitagliptin | Januvia | DPP-4 Inhibitor, incretin enhancer | 100 mg
| Not for Type 1 or for diabetic ketoacidosis | Once daily
With or without food |