8.3 Diabetes Medicines
Key Takeaways
- Metformin is the usual foundational pharmacotherapy for type 2 diabetes when tolerated and not contraindicated, with GI adverse effects and renal considerations central to counselling.
- SGLT2 inhibitors and GLP-1 receptor agonists carry important cardiorenal benefit concepts beyond glucose lowering alone.
- Sulfonylureas and insulin are high-yield hypoglycaemia-risk medicines; teach recognition and treatment of hypos.
- Insulin regimens are understood at high level as basal versus bolus (prandial) roles, not as device-specific trivia.
- Sick-day rules, foot care counselling, and HbA1c targets as individualised guideline concepts (often ~53 mmol/mol or 7% as a common adult default, adjusted to the person) are core Standard 3.2/3.3 skills.
8.3 Diabetes Medicines
Quick Answer: For type 2 diabetes, metformin is usually foundational. Add or prioritise agents with cardiorenal benefit (notably many SGLT2 inhibitors and GLP-1 receptor agonists) when indicated by guidelines and comorbidity. Respect hypoglycaemia risk with sulfonylureas and insulin. Counsel sick-day rules, hypo treatment, and foot care. Treat HbA1c targets as guideline concepts with individualisation—a common adult default discussed in practice is around 53 mmol/mol (7%), tighter or looser depending on age, comorbidities, and hypo risk.
Diabetes care is a dense Intern Written topic because it blends pharmacology, monitoring (Standard 3.3), counselling (Standard 3.2), and public health complications (neuropathy, nephropathy, retinopathy, CVD).
Metformin — foundation of type 2 therapy
Unless contraindicated or not tolerated, metformin is typically first-line pharmacotherapy for type 2 diabetes.
Counselling and safety:
- Take with food to reduce GI upset (nausea, diarrhoea, abdominal discomfort); extended-release formulations may improve tolerability.
- Dose titration often improves acceptance.
- Renal function influences use and maximum dose; significant renal impairment increases lactic acidosis concern—follow AMH renal guidance rather than guessing.
- Temporary interruption may be needed around certain contrast procedures or acute dehydrating illness (coordinate with medical advice).
- Does not usually cause hypoglycaemia alone.
Metformin addresses insulin resistance and hepatic glucose output; it is not a substitute for lifestyle measures (diet, physical activity, weight management) that remain first-order interventions.
SGLT2 inhibitors — cardiorenal concepts
Examples used in Australia include dapagliflozin, empagliflozin, and ertugliflozin (know class, not every brand). Beyond glucose lowering via urinary glucose excretion, guidelines emphasise heart failure and chronic kidney disease benefit concepts for key agents in eligible patients—sometimes even when diabetes is not the sole driver of prescribing.
Counselling priorities:
| Topic | Points |
|---|---|
| Genital hygiene | Increased genital mycotic infections; advise washing and symptom reporting |
| Volume status | Diuretic-like effect; hypotension/dehydration risk, especially with loop diuretics or illness |
| Sick days | Risk of ketoacidosis (including euglycaemic DKA) in acute illness, reduced intake, or peri-operative settings—hold per sick-day/surgical protocols |
| Urinary symptoms | Polyuria; assess UTI symptoms without missing other causes |
| Foot disease | Rare severe complications discussed historically for the class—maintain excellent foot care and escalate infection/ulcers |
SGLT2 inhibitors are not primarily hypo-causing when used alone, but combination with insulin/sulfonylurea can still produce hypos from the companion drug.
GLP-1 receptor agonists — cardiorenal and weight concepts
Injectable (and some oral) GLP-1 RAs such as semaglutide, dulaglutide, and liraglutide reduce glucose via incretin pathways, slow gastric emptying, and often support weight loss. Several have demonstrated atherosclerotic CV benefit concepts in high-risk populations.
Counselling:
- GI adverse effects (nausea, vomiting, diarrhoea, constipation) are common early; eat smaller meals, titrate as directed.
- Injection technique and site rotation for injectables; never share pens.
- Rare but serious risks include pancreatitis warning symptoms (severe abdominal pain)—seek urgent care.
- Caution with severe GI disease history; gallbladder symptoms can occur.
- Hypoglycaemia risk rises mainly when combined with insulin or sulfonylureas—dose adjustments of those agents may be needed by the prescriber.
Sulfonylureas — hypoglycaemia risk
Gliclazide (commonly modified-release), glipizide, and glibenclamide (higher hypo risk, especially in elderly) stimulate insulin release.
Key points:
- Hypoglycaemia is the major safety issue—especially with missed meals, excess alcohol, renal impairment, or dose errors.
- Counsel on regular meals, hypo recognition, and treatment.
- Weight gain can occur.
- Prefer agents/regimens with lower hypo risk in frail older adults when alternatives exist.
Insulin — basal versus bolus (high level)
Intern Written expects conceptual insulin literacy, not pump engineering.
| Role | Meaning | Examples of concept |
|---|---|---|
| Basal | Background insulin covering hepatic glucose production between meals and overnight | Long-acting analogues (e.g. insulin glargine, insulin detemir, insulin degludec) or intermediate regimens |
| Bolus (prandial) | Mealtime coverage for carbohydrate intake | Rapid-acting analogues (e.g. insulin aspart, insulin lispro, insulin glulisine) or short-acting human insulin |
| Premixed | Fixed basal+bolus combinations in one pen/vial | Useful for some patterns; less flexible for variable meals |
Safety counselling:
- Correct device priming, units, and timing relative to meals for bolus insulin.
- Never share needles/pens.
- Storage: in-use pens usually room temperature per product; unopened stock refrigerated—avoid freezing.
- Hypoglycaemia and injection-site lipohypertrophy (rotate sites).
- Sick-day insulin plans often continue basal insulin with closer monitoring—patients should have an individualised plan, not stop all insulin in type 1 diabetes (DKA risk).
Sick-day rules (exam essentials)
During vomiting, diarrhoea, fever, or poor oral intake:
- Do not stop insulin in type 1 diabetes without a medical plan—basal needs often continue.
- Check blood glucose more often; ketone testing when indicated (type 1, SGLT2 users, pregnancy contexts, marked hyperglycaemia).
- Maintain hydration if possible; seek medical care if unable to keep fluids down.
- Temporarily withhold medicines that worsen dehydration or AKI risk per plans—commonly discussed groups include SGLT2 inhibitors, and sometimes metformin/ACEI/ARB/diuretics under medical guidance (the “sick-day” medicine list concept).
- Know when to escalate: persistent vomiting, Kussmaul breathing, confusion, ketones, severe hyperglycaemia, or signs of DKA/HHS.
Hypoglycaemia recognition and treatment
Symptoms: sweating, tremor, hunger, confusion, irritability, palpitations, drowsiness; severe: seizure, coma.
Treatment concept (conscious patient able to swallow): provide rapid-acting carbohydrate (e.g. glucose tablets/gel, sugary soft drink—not “diet”), then recheck and follow with longer-acting carbohydrate as per education plan. Unconscious patients need emergency care / glucagon pathways—not oral fluids.
Identify the cause (missed meal, extra insulin, exercise, alcohol) to prevent recurrence. Document and inform the diabetes team when hypos are recurrent.
Foot care counselling
Diabetes foot disease causes preventable amputations. Pharmacist messages:
- Daily foot inspection; moisturise dry skin but not between toes if maceration risk.
- Appropriate footwear; avoid walking barefoot.
- Do not self-excise corns with blades; professional podiatry for high-risk feet.
- Urgent review for ulcers, cellulitis, black areas, new swelling, or puncture wounds.
- Support smoking cessation and glycaemic/vascular risk control.
HbA1c targets — guideline concepts without false precision
Targets are individualised. A commonly cited default adult target in many guidelines is around 53 mmol/mol (7%), but:
- Tighter targets may suit younger people with low hypo risk and long life expectancy.
- Looser targets may suit frail elderly, limited life expectancy, or high hypo/unawareness risk.
- Pregnancy and some other states use different targets under specialist care.
For the exam: state that targets are personalised, mention the ~53 mmol/mol (7%) common default concept carefully, and emphasise that medicines are adjusted based on HbA1c plus hypos, comorbidities, and patient goals—not a single universal number for every vignette.
Monitoring beyond glucose
Standard 3.3 thinking includes BP, lipids, renal function/ACR, eye screening, foot checks, and medicine adverse effects—not glucose alone. Pharmacists reinforce recall and adherence to the whole complication-prevention package.
Exam mindset
Classic items: metformin GI/renal counselling; SGLT2 genital infection or sick-day hold; GLP-1 nausea titration; sulfonylurea hypo; basal vs bolus role; type 1 sick-day insulin continuation; hypo treatment sequence; foot ulcer urgent referral; and HbA1c individualisation rather than a fabricated exact personal target for an unknown patient.
Which statement best describes metformin’s usual role in type 2 diabetes?
A patient on an SGLT2 inhibitor develops gastroenteritis with poor oral intake. Which counselling concept is most appropriate?
Which medicine group is most classically associated with hypoglycaemia risk requiring structured patient education?
How should HbA1c targets be described at intern examination level?