PSI Patient Counselling & Drug Interactions 4 — Questions and Answers
Question 1: Which key counselling message is most important for a patient newly diagnosed with type 2 diabetes starting metformin?
- GI side effects (nausea, diarrhoea) are common at the start — take with food and they usually resolve; do not stop without speaking to your pharmacist/GP (Correct answer)
- Metformin causes hypoglycaemia and you should carry dextrose tablets
- Metformin must be taken on an empty stomach
- Metformin causes weight gain
Correct answer: GI side effects (nausea, diarrhoea) are common at the start — take with food and they usually resolve; do not stop without speaking to your pharmacist/GP
GI intolerance is the most common reason for early metformin discontinuation. Taking with or after food and titrating the dose slowly significantly reduces GI side effects. Metformin does not cause hypoglycaemia alone.
Question 2: When should a patient using a reliever inhaler (salbutamol) be advised to seek urgent medical review?
- If using reliever more than 3 times per week — indicates poor asthma control requiring step-up therapy (Correct answer)
- If using it once a month
- After every use regardless of frequency
- Only if symptoms last more than 2 weeks
Correct answer: If using reliever more than 3 times per week — indicates poor asthma control requiring step-up therapy
Reliever use >3 times/week signals inadequately controlled asthma. This requires review of preventer therapy (ICS) and adherence. Dependence on reliever without preventer increases severe attack risk.
Question 3: Which interaction between alcohol and benzodiazepines is clinically important?
- Additive CNS depression — combination causes excessive sedation and respiratory depression risk (Correct answer)
- Alcohol reduces benzodiazepine effectiveness
- No clinically relevant interaction
- Alcohol prevents benzodiazepine absorption
Correct answer: Additive CNS depression — combination causes excessive sedation and respiratory depression risk
Both alcohol and benzodiazepines are CNS depressants. Combined, they produce additive sedation, impaired coordination, and potentially fatal respiratory depression. Patients must avoid alcohol during benzodiazepine treatment.
Question 4: A patient on a statin reports new onset muscle pain. The pharmacist should advise:
- Stop the statin, seek GP review — report any dark urine urgently as this may indicate rhabdomyolysis (Correct answer)
- Continue and take ibuprofen for pain
- Reduce the dose independently
- The pain is unrelated to the statin
Correct answer: Stop the statin, seek GP review — report any dark urine urgently as this may indicate rhabdomyolysis
Statin-induced myopathy ranges from mild myalgia to severe rhabdomyolysis. Dark urine (myoglobinuria) is a red flag for rhabdomyolysis — a medical emergency causing acute kidney injury. The statin must be stopped.
Question 5: Probenecid, used for gout, inhibits renal tubular secretion. Which antibiotic interaction is clinically significant?
- Probenecid blocks penicillin/amoxicillin secretion, raising antibiotic levels (formerly used therapeutically) (Correct answer)
- Probenecid increases penicillin metabolism
- Probenecid reduces penicillin absorption
- No interaction with antibiotics
Correct answer: Probenecid blocks penicillin/amoxicillin secretion, raising antibiotic levels (formerly used therapeutically)
Probenecid competitively inhibits OAT transporters in the renal tubule, blocking active secretion of penicillins and raising their plasma levels. This was historically exploited to prolong penicillin action (e.g., during wartime antibiotic shortages).
Question 6: A patient receiving intramuscular methotrexate for psoriasis asks about taking folic acid supplements. The pharmacist advises:
- Yes — folic acid 5 mg once weekly (on a different day) is routinely co-prescribed to reduce methotrexate side effects without reducing efficacy (Correct answer)
- No — folic acid completely blocks methotrexate
- Only if mouth ulcers develop
- Folic acid is irrelevant with IM methotrexate
Correct answer: Yes — folic acid 5 mg once weekly (on a different day) is routinely co-prescribed to reduce methotrexate side effects without reducing efficacy
Folic acid supplementation with methotrexate reduces toxicity (mouth ulcers, GI side effects, liver toxicity, cytopenias) without significantly compromising its anti-inflammatory effect. It is routinely co-prescribed.
PSI Patient Counselling & Drug Interactions 4
Which key counselling message is most important for a patient newly diagnosed with type 2 diabetes starting metformin?