Type 2 Diabetes & Insulin therapy (T2DM)

• Establish thirst, polyuria/nocturia, unexplained tiredness or weight loss?

• Determine age and ethnicity (South Asian, African-Caribbean, Black African carry earlier, higher risk)?

• Ask about blurred vision or sudden change in eyesight?

• Check family history of diabetes, and any gestational diabetes or PCOS?

• Ask about recurrent infections (thrush, balanitis, urinary) or slow-healing cuts?

• Identify obesity, hypertension, chronic kidney disease or cardiovascular disease?

• Screen for DKA / HHS features – nausea, abdominal pain, drowsiness, breathlessness, extreme thirst?

• Identify diabetogenic drugs (corticosteroids, atypical antipsychotics, thiazides)?

• In established diabetes, ask about hypoglycaemia frequency, and waking headaches suggesting nocturnal hypos?

• Explore diet, physical activity, smoking and alcohol?

• In those on insulin, confirm full hypoglycaemia awareness and any injection-site problems (lumps, pain, leakage)?

• Ask whether they drive (Group 1 or 2), do shift work, travel across time zones, or plan to fast (e.g. Ramadan)?

➤ "Explore the patient's understanding of diabetes and any concerns about needles, weight gain or hypos, and what a diagnosis means to them?"

➤ "Ask how managing blood glucose affects their work, driving and sleep, and what the barriers to dietary and lifestyle change might be?"

➤ Diabetic ketoacidosis → hyperglycaemia with ketosis and acidosis (vomiting, abdominal pain, Kussmaul breathing) → emergency admission

➤ Hyperosmolar hyperglycaemic state → profound dehydration, altered consciousness, glucose often > 30 mmol/L without significant ketosis → emergency admission

➤ Severe hypoglycaemia needing third-party help, or impaired hypoglycaemia awareness → treat and reassess regimen / driving

➤ Active or limb-threatening diabetic foot → ulceration with fever/sepsis, deep infection, critical ischaemia or gangrene → urgent foot team

➤ Sudden visual loss → rubeosis iridis, vitreous/pre-retinal haemorrhage, retinal detachment, or NAION (semaglutide) → emergency ophthalmology

➤ New-onset diabetes with unexplained weight loss in those over 60 → suspect pancreatic cancer

• BMI and waist circumference – anchor for weight-management and remission discussions.

• Blood pressure at diagnosis and annually, including lying/standing readings to detect autonomic postural drop.

• Diabetic foot examination – 10 g monofilament sensation, foot pulses/ABPI, and inspection for ulcers, calluses, deformity or Charcot change.

• Injection sites (in those on insulin) – palpate for lipohypertrophy or cutaneous amyloidosis, and observe technique and site rotation.

• Skin and complications – acanthosis nigricans, peripheral oedema, and confirm retinal screening is up to date.

Type 2 diabetes means your body can't use insulin properly, so your blood sugar runs high.
We manage it together with healthy eating, activity and weight loss, plus tablets and sometimes injections to protect your heart, kidneys, eyes and feet.
The most powerful things you can do are lose some weight, stay active and stop smoking – in some people this can even push the diabetes into remission.

⚠️ Common pitfall

Diagnosing on a single HbA1c, or trusting it when it is unreliable. In an asymptomatic person one raised HbA1c is not enough – repeat to confirm. And HbA1c is misleading (falsely low or high) in pregnancy, recent blood loss or transfusion, haemoglobinopathy, haemolysis, advanced CKD and rapid-onset diabetes – use fasting or random glucose instead.

• Refer to structured education (e.g. DESMOND) and a dietitian at diagnosis, and reinforce lifestyle change.

• Suspected DKA or HHS → immediate hospital admission.

• Agree an individualised HbA1c target – usually 48 mmol/mol (lifestyle ± metformin) or 53 mmol/mol (on hypo-causing drugs).

• Severe hypoglycaemia → fast-acting carbohydrate if conscious; IM glucagon or IV glucose if not – call 999.

• Start metformin + an SGLT-2 inhibitor for almost everyone, with profile-based add-ons (see Choosing & Escalating Therapy and the drug-class sections that follow).

• Active diabetic foot (ulcer, spreading infection, gangrene) → urgent multidisciplinary foot team.

• Annual review – HbA1c, BP, lipids, ACR, eGFR, feet, eyes, BMI and (if relevant) injection sites.

• Symptomatic hyperglycaemia despite optimal oral therapy → initiate insulin or seek specialist advice.

• Cardiovascular and renal protection for all – statin, blood-pressure control, smoking cessation.

🔑 Key principle – treat the cardiovascular and renal risk, not just the HbA1c

Since the February 2026 update to NICE NG28, the default for almost everyone is metformin AND an SGLT-2 inhibitor from diagnosis, introduced sequentially – because the cardiorenal benefit matters as much as glucose-lowering. Most people with type 2 diabetes ultimately die of cardiovascular disease, so keep the SGLT-2 inhibitor for that protection even when the HbA1c target is met.

➤ No relevant comorbidity / obesity

→ MR metformin + an SGLT-2 inhibitor (SGLT-2 inhibitor alone if metformin contraindicated) → if more control is needed, add a DPP-4 inhibitor, then a sulfonylurea, pioglitazone or insulin. In obesity, consider a GLP-1 RA or tirzepatide as the first add-on.

➤ Atherosclerotic cardiovascular disease (ASCVD)

→ Triple first-line: MR metformin + an SGLT-2 inhibitor + subcutaneous semaglutide (Ozempic, up to 1 mg/week) for cardiorenal benefit → then a sulfonylurea, pioglitazone or insulin if needed. Only sc semaglutide is recommended in this slot.

➤ Early-onset (diagnosis under 40)

→ MR metformin + an SGLT-2 inhibitor, and consider adding a GLP-1 RA or tirzepatide (higher lifetime risk) → otherwise a DPP-4 inhibitor, then sulfonylurea, pioglitazone or insulin.

➤ Chronic kidney disease

→ eGFR > 30: MR metformin + an SGLT-2 inhibitor. eGFR 20–30: dapagliflozin or empagliflozin + a DPP-4 inhibitor. eGFR < 20: a DPP-4 inhibitor, then pioglitazone or insulin.

➤ Heart failure

→ MR metformin + an SGLT-2 inhibitor → add a DPP-4 inhibitor, then a sulfonylurea or insulin. Avoid pioglitazone (fluid retention).

➤ Frailty

→ MR metformin; use an SGLT-2 inhibitor only if the risk of volume depletion/hypotension is low → add a DPP-4 inhibitor, then cautiously pioglitazone, a sulfonylurea or insulin (mindful of falls and hypoglycaemia).

• Introduce drugs sequentially, maximising the tolerated dose and checking tolerability before adding the next.

• Keep the SGLT-2 inhibitor for cardiorenal protection even when the HbA1c target is met.

• Never combine a GLP-1 RA (or tirzepatide) with a DPP-4 inhibitor – both act on the incretin system; stop the gliptin when starting the GLP-1.

• When adding a GLP-1 RA to a sulfonylurea or insulin, reduce the older drug to limit hypos; a GLP-1 RA plus insulin needs specialist support.

• For symptomatic hyperglycaemia, give prompt rescue – a sulfonylurea (stable patient) or insulin (severe weight loss, ketosis, or possible type 1) – then step back once glucose toxicity clears.

➤ Where it sits – first-line for all (with an SGLT-2 inhibitor) unless contraindicated or not tolerated; retained at every later step.

➤ Who benefits – essentially every patient who can tolerate it; especially valued where weight gain and hypoglycaemia must be avoided.

➤ Agents & doses

• MR metformin (now NICE-preferred) – start 500 mg OD with the evening meal; titrate every 10–15 days to a max of 2 g OD (or 1 g BD).
• Standard-release – 500 mg OD with breakfast, increasing by 500 mg weekly to a max of 2 g/day in divided doses; preferred where there is dysphagia (can be crushed or given as liquid).

➤ Primary-care precautions & monitoring – check eGFR: review the dose if < 45 and stop if < 30; monitor for GI upset (switch SR→MR or retitrate) and vitamin B12 deficiency on long-term use.

➤ Problem groups / withhold – suspend during acute illness, dehydration, AKI risk, hypoxia, sepsis, or before contrast/surgery; rare but serious lactic acidosis; avoid in significant hepatic impairment.

➤ Where it sits – first-line with metformin for almost everyone (or alone if metformin is contraindicated); a cornerstone in heart failure and chronic kidney disease.

➤ Who benefits most – heart failure, CKD with albuminuria, established cardiovascular disease, and those needing weight-favourable, hypo-sparing therapy.

➤ Agents & doses

• Dapagliflozin 10 mg OD – licensed in CKD down to eGFR 15; NICE-supported as the least costly option.
• Empagliflozin 10 mg OD (max 25 mg) – do not initiate if eGFR < 30 (< 20 in heart failure).
• Canagliflozin 100 mg OD (max 300 mg) – avoid in active foot disease/PAD (lower-limb amputation signal).
• Ertugliflozin 5 mg OD (max 15 mg) – glycaemic indication only; do not initiate if eGFR < 60.

➤ Primary-care precautions & monitoring – counsel on DKA warning signs and genital/urinary infection; expect a small early eGFR dip; caution with diuretics (volume depletion); urgent assessment for perineal pain/swelling (rare Fournier's gangrene).

➤ Problem groups / suspend – withhold during acute illness, dehydration, surgery or a very low-carbohydrate diet; avoid with recurrent genital infection, or active foot disease (canagliflozin); not for type 1 diabetes in primary care.

🧠 Clinical pearl

Euglycaemic DKA. An SGLT-2 inhibitor can precipitate ketoacidosis with only modestly raised – or even near-normal – glucose, so a normal reading does not exclude it. In any unwell patient on one, check ketones whatever the glucose, and suspend the drug during acute illness, dehydration, surgery or a very low-carbohydrate diet.

➤ Where it sits – the usual first add-on after metformin + SGLT-2 inhibitor when more glucose-lowering is needed (unless a GLP-1 RA/tirzepatide is prioritised).

➤ Who benefits – frail or older patients and those with renal impairment where hypoglycaemia must be avoided; linagliptin needs no dose adjustment in CKD.

➤ Agents & doses

• Sitagliptin 100 mg OD (50 mg if eGFR 30–45; 25 mg if < 30).
• Linagliptin 5 mg OD – no renal or hepatic adjustment (useful in CKD).
• Alogliptin 25 mg OD (12.5 mg / 6.25 mg by renal function) – watch for bullous pemphigoid / Stevens-Johnson.
• Saxagliptin 5 mg OD (2.5 mg in renal impairment) – caution in heart failure.
• Vildagliptin 50 mg BD (50 mg OD with a sulfonylurea or in renal impairment) – check LFTs; avoid in moderate–severe heart failure.

➤ Primary-care precautions & monitoring – reduce a concurrent sulfonylurea to limit hypos; seek urgent help for severe persistent abdominal pain (pancreatitis); check LFTs with vildagliptin.

➤ Problem groups / avoid – never with a GLP-1 RA or tirzepatide; avoid in DKA; history of pancreatitis; heart-failure cautions (saxagliptin, vildagliptin).

➤ Where it sits – a later add-on (after metformin, SGLT-2 inhibitor ± DPP-4 inhibitor/GLP-1), or earlier when rapid symptom relief is needed or cost is decisive.

➤ Who benefits – patients with marked symptomatic hyperglycaemia needing quick control, or where other agents are unsuitable or unaffordable.

➤ Agents & doses

• Gliclazide (UK first choice) 40–80 mg OD, max 320 mg/day (divide if > 160 mg); MR 30 mg OD, max 120 mg.
• Glimepiride 1 mg OD with the first meal, max 4 mg/day – high prolonged-hypo risk in the elderly.
• Glipizide 2.5–5 mg OD before food, max 20 mg/day (reduce in hepatic impairment).
• Tolbutamide 0.5–1.5 g/day (max 2 g) – shorter-acting, usable in renal impairment.

➤ Primary-care precautions & monitoring – counsel on hypoglycaemia and driving (DVLA-notifiable); beta-blockers mask warning signs; advise on weight; reduce the dose when adding a GLP-1 RA or insulin.

➤ Problem groups / caution – elderly and renal impairment (prolonged hypos – prefer gliclazide/tolbutamide); avoid in DKA, severe hepatic impairment and G6PD deficiency; relevant to occupational drivers.

➤ Where it sits – a later add-on when other agents are unsuitable; useful where hypoglycaemia must be avoided and there is marked insulin resistance.

➤ Who benefits – patients needing a hypo-free oral option without renal dose limits; sometimes considered alongside metabolic-associated steatotic liver disease.

➤ Agents & doses

• Pioglitazone 15–30 mg OD, max 45 mg (start 15 mg in the elderly).

➤ Primary-care precautions & monitoring – watch for fluid retention and weight gain; check LFTs at baseline and review; counsel on a small increased fracture risk; review response at 3–6 months and stop if inadequate.

➤ Problem groups / avoid – heart failure (or a history of it), bladder cancer or unexplained macroscopic haematuria, and significant hepatic impairment.

➤ Where it sits (NICE NG28, 2026)

• ASCVD – subcutaneous semaglutide (Ozempic, up to 1 mg/week) within first-line triple therapy (only sc semaglutide is recommended here, for cardiorenal protection).
• Early-onset (< 40) or obesity needing further control – consider a GLP-1 RA or tirzepatide as first-line triple or first add-on.
• Otherwise – an option after triple therapy where weight loss or avoiding insulin matters.

➤ Who benefits – obesity, established ASCVD (semaglutide), early-onset disease, and those for whom insulin has occupational implications or weight loss would benefit obesity-related comorbidity.

➤ Agents & doses

• Tirzepatide (Mounjaro, dual GIP/GLP-1) 2.5 mg weekly ×4 weeks → 5 mg, then in 2.5 mg steps to max 15 mg.
• Semaglutide (Ozempic, subcutaneous) 0.25 mg weekly ×4 weeks → 0.5 mg → max 1 mg/week (NG28 cap); the oral form is Rybelsus.
• Dulaglutide (Trulicity) 0.75–1.5 mg weekly.
• Liraglutide (Victoza) 0.6 mg OD → max 1.8 mg.

➤ When to continue – the 6-month rule – only continue a GLP-1 RA or tirzepatide if there is a beneficial metabolic response at 6 months: a fall in HbA1c of at least 11 mmol/mol (1.0%) and weight loss of at least 3% of initial body weight. If both are not met, stop and move to the next option.

➤ Primary-care precautions & monitoring – expect transient GI upset and delayed gastric emptying; advise effective contraception and stop before a planned pregnancy (strengthen contraception with tirzepatide at initiation and each escalation); for semaglutide, warn about rare NAION – urgent ophthalmology for sudden painless vision loss – and ask about privately-bought semaglutide.
➤ NAION (Non-Arteritic Anterior Ischaemic Optic Neuropathy): It is a sudden loss of blood supply to the optic nerve, causing acute, painless vision loss in one eye.

➤ Problem groups / avoid – never with a DPP-4 inhibitor; history of pancreatitis (stop if suspected); stop if BMI falls below 18.5; caution with personal/family history of medullary thyroid cancer or MEN2 (liraglutide); a GLP-1 RA plus insulin needs specialist support.

⚠️ Common pitfall

Doubling up incretins, or prescribing a withdrawn drug. Never run a GLP-1 RA (or tirzepatide) alongside a DPP-4 inhibitor – there is no added benefit, so stop the gliptin when starting the GLP-1. And do not newly initiate exenatide (Byetta/Bydureon), which is discontinued in the UK – switch any remaining patients to semaglutide, dulaglutide or tirzepatide.

• HbA1c remains above the individualised target (commonly ≥ 58 mmol/mol) despite optimised oral ± non-insulin injectable therapy.

• Symptomatic / catabolic hyperglycaemia – osmotic symptoms, marked hyperglycaemia, weight loss or ketosis – give insulin promptly and consider possible type 1 diabetes or a pancreatic cause.

• When other agents are contraindicated or not tolerated, or rapid control is needed peri-operatively or in acute illness.

➤ First-line basal – human NPH (isophane) insulin once or twice daily (e.g. Insulatard, Humulin I, Insuman Basal). Continue metformin; review the sulfonylurea (reduce or stop to limit hypos).

➤ Long-acting analogue (recurrent hypos, carer-administered once-daily dosing, or where NPH timing is impractical) – glargine (Lantus, Abasaglar, Semglee; Toujeo U300) or degludec (Tresiba). Prescribe analogues/biosimilars by brand.

➤ Withdrawal note – do not initiate insulin detemir (Levemir); it is being withdrawn (UK supply ends December 2026), so switch existing patients to glargine or degludec in good time.

➤ Titrate & intensify – self-titrate to a fasting glucose of 5–7 mmol/L; if basal alone is insufficient, add rapid-acting insulin before the largest meal, or switch to a biphasic insulin (e.g. Humulin M3, NovoMix 30).

➤ Education & safety – teach injection technique and site rotation, hypoglycaemia recognition and treatment, sick-day rules (never stop insulin), and DVLA duties.

• Blood pressure – an ACE inhibitor or ARB first-line (especially with albuminuria); target < 140/90, or < 130/80 if ACR ≥ 70 mg/mmol. Do not combine an ACE inhibitor with an ARB.

• Lipids – atorvastatin 20 mg for primary prevention; 80 mg for established cardiovascular disease.

• Antiplatelet – not routine for primary prevention; offer where there is established atherosclerotic cardiovascular disease.

• Cardiorenal drugs – keep the SGLT-2 inhibitor for heart and kidney protection; sc semaglutide adds cardiorenal benefit in ASCVD.

• Lifestyle – smoking cessation, weight management and activity remain central to cardiovascular risk reduction.

• Monitor – annual ACR and eGFR, blood pressure, lipids and cardiovascular risk; review feet, eyes and injection sites.

📌 DVLA – diabetes and fitness to drive

• Group 1 (car / motorcycle): on insulin → must notify DVLA; the licence is reviewed and issued for 1, 2 or 3 years if criteria are met (adequate hypo awareness; no more than one severe hypoglycaemia – needing another person's help – while awake in the past 12 months; appropriate glucose monitoring; under regular review).
On a sulfonylurea or glinide → notify DVLA. On metformin, an SGLT-2 inhibitor, a DPP-4 inhibitor or a GLP-1 RA alone → usually no need to notify unless complications develop.

• Group 2 (bus / lorry): on insulin or a sulfonylurea/glinide → must notify DVLA; stricter individual assessment with an annual independent specialist review for insulin.
A single episode of severe hypoglycaemia (even while asleep) means stop driving and notify. Full hypoglycaemia awareness is required. From 7 November 2025, an approved continuous glucose monitor may be used for Group 2 monitoring, but finger-prick equipment must still be carried.

• Safe-driving rules (both groups) – “5 to drive”: check glucose within 2 hours before driving and every 2 hours on long journeys; ensure glucose is above 5.0 mmol/L before driving (have a snack if it is 5.0 mmol/L or below); do not drive if below 4.0 mmol/L or if hypoglycaemic / awareness is impaired.
If a hypo occurs while driving, stop safely, switch off, move out of the driver's seat, treat, and wait at least 45 minutes after glucose returns to 5.0 mmol/L or above. Always carry a fast-acting carbohydrate.

• Suspected DKA or HHS, or severe hypoglycaemia needing third-party help → emergency admission (999)

• Structured education (DESMOND) at diagnosis; annual diabetic eye screening

• Active / limb-threatening diabetic foot (ulcer, spreading infection, gangrene, critical ischaemia) → urgent multidisciplinary foot team

• Podiatry for moderate / high-risk feet

• Sudden visual loss (NAION, rubeosis iridis, retinal detachment, vitreous haemorrhage) → emergency ophthalmology

• Dietitian for nutrition / weight management; consider the Path to Remission Programme

• New diabetes + unexplained weight loss in those over 60 → urgent pancreatic cancer pathway

• Specialist diabetes team if HbA1c suboptimal despite optimised therapy / titration, complex regimens, or to add a GLP-1 RA to insulin

• Paediatric diabetes team for any child / young person with suspected type 2 diabetes

🧭 AKT – high-yield facts

• Diagnose on HbA1c ≥ 48 mmol/mol (or FPG ≥ 7.0, or random ≥ 11.1 with symptoms); repeat to confirm if asymptomatic; pre-diabetes 42–47 mmol/mol.

• HbA1c targets: 48 mmol/mol (lifestyle ± metformin) or 53 mmol/mol (drugs that can cause hypoglycaemia); consider insulin if HbA1c stays ≥ 58 mmol/mol.

• First-line (NG28, 2026): MR metformin + an SGLT-2 inhibitor for nearly everyone; add subcutaneous semaglutide (Ozempic, ≤ 1 mg/week) for established ASCVD; consider a GLP-1 RA or tirzepatide in early-onset (under 40).

• Continuation rule – only continue a GLP-1 RA or tirzepatide if, at 6 months, HbA1c has fallen ≥ 11 mmol/mol (1.0%) and weight has fallen ≥ 3%; otherwise stop.

• First-line basal insulin is NPH (isophane); titrate to fasting glucose 5–7 mmol/L.

• Most patients with type 2 diabetes die of cardiovascular disease – SGLT-2 inhibitors and GLP-1 RAs are chosen for cardiorenal as much as glycaemic benefit.

• Never co-prescribe a GLP-1 RA with a DPP-4 inhibitor; in acute illness, stop the SGLT-2 inhibitor and check ketones (euglycaemic DKA).

• Red flags: new diabetes + weight loss in the over-60s → think pancreatic cancer; DKA / HHS need admission.

• DVLA: insulin → notify; “5 to drive” (above 5.0 to drive, never below 4.0); Group 2 stricter – a single severe hypo means stop and notify.

🎯 SCA

A 54-year-old lorry driver with a Group 2 licence attends having been newly diagnosed with type 2 diabetes; his HbA1c is 85 mmol/mol and he describes thirst, nocturia and recent weight loss. He would benefit from prompt glycaemic control, but the agents that act fastest – a sulfonylurea or insulin – both carry a risk of hypoglycaemia and trigger DVLA notification with potential restrictions on his vocational licence, on which his livelihood depends. He is anxious about losing his job and reluctant to start insulin.

A strong consultation explores his ideas, concerns and expectations – his fears about insulin, hypos and his licence, and the impact on work and income; explains the options honestly, including that metformin and an SGLT-2 inhibitor (with a GLP-1 RA if needed) lower glucose effectively, protect the heart and kidneys and do not usually require DVLA notification, while being clear that if symptoms or control demand a sulfonylurea or insulin, notification and temporary restrictions would follow; agrees a shared plan with prompt review of symptoms and HbA1c; and provides robust safety-netting for hypoglycaemia and for DKA – all while respecting his autonomy and showing empathy for what is, for him, a genuinely high-stakes diagnosis.