1. A 23-year-old woman presents to A&E 6 hours after taking thirty-two 500 mg paracetamol tablets. She feels nauseated but has normal observations. Blood tests and a paracetamol concentration are being arranged.
Which ONE of the following is the most appropriate management principle?
A. Reassure because symptoms are mild.
B. Wait 24 hours to see if liver enzymes rise.
C. Assess urgently using paracetamol overdose guidance and start acetylcysteine if indicated.
D. Treat with naloxone.
E. Give vitamin K as the antidote.
2. A 58-year-old man with chronic cancer pain is found very drowsy after an increase in modified-release morphine. His respiratory rate is 7 breaths/minute and pupils are pinpoint.
Which ONE of the following is the most appropriate immediate action?
A. Give the next dose of modified-release morphine early.
B. Treat as sepsis and give broad-spectrum antibiotics only.
C. Reassure because drowsiness means analgesia is effective.
D. Give flumazenil.
E. Urgently assess for opioid toxicity and consider naloxone with supportive care.
3. A 72-year-old woman taking lithium develops vomiting and diarrhoea after gastroenteritis. She now has coarse tremor, unsteady gait, slurred speech and confusion. She also takes ramipril.
Which ONE of the following is the most appropriate pharmacist action?
A. Arrange urgent assessment for possible lithium toxicity and check lithium level, renal function and electrolytes.
B. Reassure because tremor is always a harmless lithium adverse effect.
C. Advise taking an extra lithium dose after vomiting.
D. Recommend ibuprofen for dehydration symptoms.
E. Stop all medicines permanently without clinical review.
4. An 81-year-old man taking digoxin for atrial fibrillation develops nausea, visual disturbance, confusion and new bradycardia. His renal function has recently worsened after starting a diuretic.
Which ONE of the following is the most appropriate concern?
A. Expected age-related visual change.
B. Uncomplicated viral gastroenteritis.
C. Poor adherence to digoxin.
D. Digoxin toxicity requiring urgent clinical assessment.
E. Isolated iron deficiency.
5. A 64-year-old woman with rheumatoid arthritis accidentally takes methotrexate 15 mg daily for 6 days instead of once weekly. She reports mouth ulcers, bruising and nausea.
Which ONE of the following is the most appropriate action?
A. Advise continuing daily methotrexate until symptoms settle.
B. Arrange urgent assessment for possible methotrexate toxicity.
C. Recommend taking folic acid only and waiting for routine review.
D. Reassure because methotrexate dosing errors are rarely harmful.
E. Treat as uncomplicated reflux.
6. A 76-year-old man with gout is prescribed colchicine for a flare. He has chronic kidney disease and is also taking clarithromycin for pneumonia. He develops severe diarrhoea and abdominal pain.
Which ONE of the following is the most appropriate pharmacist concern?
A. Colchicine is ineffective if diarrhoea occurs.
B. Clarithromycin reduces colchicine exposure.
C. The symptoms prove gout has resolved.
D. Diarrhoea is unrelated to colchicine.
E. Colchicine toxicity risk is increased by renal impairment and interacting medicines.
7. A 67-year-old man receiving gentamicin for Gram-negative sepsis reports new tinnitus, dizziness and reduced hearing. His renal function is deteriorating.
Which ONE of the following is the most appropriate action?
A. Escalate urgently because aminoglycoside ototoxicity and nephrotoxicity should be considered.
B. Reassure because tinnitus is expected and harmless.
C. Increase the gentamicin dose to improve infection control.
D. Ignore renal function if the infection is severe.
E. Treat with earwax-softening drops.
8. A 59-year-old woman receiving intravenous vancomycin has a high trough concentration and rising creatinine. She is also prescribed piperacillin/tazobactam.
Which ONE of the following is the most appropriate pharmacist contribution?
A. Give the next vancomycin dose early.
B. Stop monitoring because the level confirms efficacy.
C. Switch to oral vancomycin for bloodstream infection.
D. Review dosing, levels, renal function and nephrotoxic risk with the clinical team before further doses.
E. Add gentamicin routinely.
9. A 74-year-old man taking warfarin for atrial fibrillation has an INR of 8.5. He has no bleeding, is haemodynamically stable and has no recent trauma. He recently started metronidazole.
Which ONE of the following is the most appropriate management principle?
A. Continue warfarin unchanged.
B. Withhold warfarin and manage according to local high-INR protocol, considering vitamin K depending on risk.
C. Give alteplase.
D. Double the warfarin dose because the INR is high.
E. Start aspirin to prevent clotting.
10. A 68-year-old woman taking apixaban presents with black stools, dizziness and hypotension. She has recently been using ibuprofen for back pain.
Which ONE of the following is the most appropriate action?
A. Reassure because DOACs do not cause serious bleeding.
B. Advise taking apixaban with food and review in one week.
C. Arrange urgent assessment for possible gastrointestinal bleeding and review anticoagulant and NSAID use.
D. Add aspirin for gastric protection.
E. Recommend loperamide.
11. A 33-year-old man taking sertraline is prescribed tramadol for acute back pain. Two days later he develops agitation, sweating, diarrhoea, tremor and muscle twitching.
Which ONE of the following should be suspected?
A. Neuroleptic malignant syndrome.
B. Opioid withdrawal only.
C. Anticholinergic toxicity.
D. Serotonin syndrome.
E. Digoxin toxicity.
12. A 45-year-old man taking haloperidol develops fever, severe muscle rigidity, confusion and autonomic instability. Creatine kinase is markedly raised.
Which ONE of the following is the most appropriate action?
A. Arrange urgent assessment for possible neuroleptic malignant syndrome.
B. Increase haloperidol dose.
C. Treat as mild extrapyramidal symptoms only.
D. Reassure because fever is expected with antipsychotics.
E. Give loperamide.
13. A 19-year-old woman is brought to A&E after taking an unknown quantity of amitriptyline. She is drowsy, hypotensive and has a broad-complex tachycardia on ECG.
Which ONE of the following is the most appropriate concern?
A. Uncomplicated sedation only.
B. Acute opioid toxicity.
C. Simple allergic reaction.
D. Isolated hypoglycaemia.
E. Tricyclic antidepressant toxicity requiring urgent management.
14. A 71-year-old man accidentally takes extra promethazine and oxybutynin. He is confused, flushed, dry-mouthed and has urinary retention with dilated pupils.
Which ONE of the following toxidrome is most likely?
A. Cholinergic toxicity.
B. Serotonin syndrome.
C. Anticholinergic toxicity.
D. Opioid toxicity.
E. Salicylate poisoning.
15. A 16-year-old presents after taking a large quantity of aspirin. She has tinnitus, vomiting, sweating and tachypnoea.
Which ONE of the following is the most appropriate management principle?
A. Reassure because tinnitus suggests a mild adverse effect only.
B. Urgently assess for salicylate poisoning, including acid-base status and salicylate concentration.
C. Treat with naloxone.
D. Give vitamin K as the antidote.
E. Advise oral fluids and discharge without blood tests.
16. A 55-year-old man with COPD takes theophylline. He is prescribed ciprofloxacin and later develops nausea, tremor, palpitations and a seizure.
Which ONE of the following is the most appropriate interpretation?
A. Ciprofloxacin reduces theophylline toxicity risk.
B. Symptoms are typical of uncomplicated COPD.
C. Seizure proves poor inhaler technique.
D. Theophylline toxicity should be suspected, especially with an interacting medicine.
E. Theophylline toxicity causes only constipation.
17. A 78-year-old woman with type 2 diabetes takes gliclazide. She is found confused and sweaty after missing meals during a vomiting illness. Capillary glucose is 2.4 mmol/L.
Which ONE of the following is the most appropriate immediate management?
A. Treat hypoglycaemia promptly and consider prolonged monitoring because sulfonylurea hypoglycaemia can recur.
B. Give rapid-acting insulin.
C. Reassure because gliclazide cannot cause hypoglycaemia.
D. Give loperamide first.
E. Withhold all carbohydrates.
18. A 3-year-old child is brought to hospital after swallowing several iron tablets. The child has vomiting, abdominal pain and bloody diarrhoea.
Which ONE of the following is the most appropriate action?
A. Reassure because iron overdose is harmless in children.
B. Give oral calcium as the antidote.
C. Advise waiting at home unless stools turn black.
D. Treat with paracetamol only.
E. Arrange urgent toxicology assessment because iron poisoning can be serious.
19. A 62-year-old man taking simvastatin is prescribed clarithromycin. A few days later he develops severe muscle pain, weakness and dark urine.
Which ONE of the following is the most appropriate concern?
A. Expected statin muscle ache requiring no action.
B. Acute gout.
C. Statin-associated rhabdomyolysis, potentially precipitated by interaction.
D. Uncomplicated urinary tract infection only.
E. Serotonin syndrome.
20. A patient taking prednisolone 40 mg daily for 8 weeks stops it abruptly. Two days later he develops weakness, dizziness, nausea and postural hypotension.
Which ONE of the following is the most appropriate concern?
A. Corticosteroid-induced hyperglycaemia only.
B. Adrenal insufficiency due to abrupt corticosteroid withdrawal.
C. Opioid toxicity.
D. Lithium toxicity.
E. Iron overdose.
21. A 70-year-old man taking ramipril and spironolactone is prescribed trimethoprim for a urinary tract infection. He later develops muscle weakness and palpitations. Blood tests show potassium 6.4 mmol/L.
Which ONE of the following is the most appropriate interpretation?
A. Trimethoprim protects against hyperkalaemia.
B. Potassium 6.4 mmol/L is clinically insignificant.
C. Spironolactone prevents medicine interactions.
D. The symptoms suggest hypokalaemia.
E. Medicine-associated hyperkalaemia should be suspected and managed urgently.
22. A patient accidentally applies too many fentanyl patches and is also using a heating pad over the patch site. They become drowsy with slow breathing.
Which ONE of the following is the most appropriate pharmacist advice?
A. Apply another patch to maintain pain control.
B. Continue heat because it improves patch adhesion.
C. Remove excess patches, avoid heat exposure and seek urgent assessment for opioid toxicity.
D. Cut the patches in half to reduce dose.
E. Take oral codeine to reverse the effect.
23. A 69-year-old man taking amiodarone develops weight loss, tremor, sweating and palpitations. Thyroid function tests show suppressed TSH and raised free T4.
Which ONE of the following is the most appropriate concern?
A. Amiodarone-associated thyrotoxicosis.
B. Digoxin toxicity.
C. Lithium-induced hypothyroidism.
D. Methotrexate toxicity.
E. Opioid withdrawal.
24. A patient using topical timolol eye drops for glaucoma develops bradycardia, dizziness and worsening wheeze. He has asthma and is also prescribed bisoprolol.
Which ONE of the following is the most appropriate pharmacist action?
A. Reassure because eye drops cannot cause systemic effects.
B. Advise doubling salbutamol and continuing all medicines.
C. Stop all glaucoma medicines permanently.
D. Review urgently because topical beta-blockers can cause systemic beta-blockade and bronchospasm.
E. Treat as allergic conjunctivitis.
25. A 5-year-old child accidentally drinks a bottle of methadone oral solution belonging to a family member. The child is currently awake but sleepy.
Which ONE of the following is the most appropriate action?
A. Observe at home because the child is still awake.
B. Give oral naloxone at home and avoid hospital.
C. Encourage vomiting to remove the methadone.
D. Give activated charcoal only and discharge.
E. Arrange emergency assessment because methadone overdose can cause delayed life-threatening respiratory depression.
Drug Toxicity Questions
Answers and Rationale
1. C
Paracetamol overdose can cause delayed hepatotoxicity even when early symptoms are mild. Management depends on timing, dose, paracetamol concentration and risk assessment, with acetylcysteine used when indicated.
2. E
Drowsiness, bradypnoea and pinpoint pupils after opioid dose escalation suggest opioid toxicity. Immediate assessment, airway and breathing support and naloxone may be required.
3. A
Vomiting, diarrhoea, dehydration and ACE inhibitor use can increase lithium toxicity risk. Coarse tremor, ataxia, dysarthria and confusion are red flags requiring urgent levels and renal/electrolyte assessment.
4. D
Nausea, visual disturbance, confusion and bradycardia in a patient with worsening renal function suggest digoxin toxicity. Electrolytes, renal function, ECG and digoxin concentration should be reviewed urgently.
5. B
Daily methotrexate dosing is a serious medication error. Mouth ulcers, bruising and nausea may indicate bone marrow suppression or mucosal toxicity, requiring urgent assessment.
6. E
Colchicine toxicity can be severe and is more likely with renal impairment and CYP3A4/P-glycoprotein inhibitors such as clarithromycin. Severe gastrointestinal symptoms may be an early warning sign.
7. A
Gentamicin can cause nephrotoxicity and ototoxicity. New tinnitus, dizziness or hearing loss with deteriorating renal function should be escalated urgently and dosing reviewed.
8. D
High vancomycin levels and rising creatinine increase nephrotoxicity risk. Further dosing should be reviewed against levels, renal function, timing and other nephrotoxic medicines.
9. B
A very high INR increases bleeding risk, and metronidazole can potentiate warfarin. Management usually involves withholding warfarin and following local high-INR protocols, with vitamin K depending on risk and bleeding status.
10. C
Black stools, hypotension and dizziness in a patient taking apixaban and ibuprofen suggest gastrointestinal bleeding. Urgent assessment and review of anticoagulant and NSAID use are needed.
11. D
Sertraline plus tramadol increases serotonergic activity. Agitation, sweating, diarrhoea, tremor and muscle twitching suggest serotonin syndrome.
12. A
Fever, severe rigidity, confusion, autonomic instability and raised creatine kinase in a patient taking antipsychotics suggest neuroleptic malignant syndrome. This is a medical emergency.
13. E
Tricyclic antidepressant overdose can cause coma, hypotension, seizures and life-threatening arrhythmias. Broad-complex tachycardia is a red flag requiring urgent management.
14. C
Confusion, flushing, dry mouth, urinary retention and dilated pupils after promethazine and oxybutynin suggest anticholinergic toxicity.
15. B
Salicylate poisoning can cause tinnitus, vomiting, sweating, tachypnoea and acid-base disturbance. Urgent assessment, salicylate concentration and blood gas evaluation are needed.
16. D
Theophylline has a narrow therapeutic index. Ciprofloxacin can increase theophylline levels, and nausea, tremor, palpitations and seizures are concerning for toxicity.
17. A
Sulfonylureas can cause prolonged or recurrent hypoglycaemia, especially with missed meals or acute illness. Immediate treatment and observation may be required.
18. E
Iron poisoning in children can be life-threatening. Vomiting, abdominal pain and bloody diarrhoea after ingestion require urgent toxicology assessment.
19. C
Clarithromycin can increase simvastatin exposure, increasing rhabdomyolysis risk. Severe muscle symptoms and dark urine require urgent assessment of creatine kinase and renal function.
20. B
Abrupt cessation after prolonged systemic corticosteroid treatment can cause adrenal insufficiency. Weakness, nausea, dizziness and postural hypotension are concerning features.
21. E
Trimethoprim can increase potassium, especially with ACE inhibitors and spironolactone. Potassium of 6.4 mmol/L with symptoms requires urgent management.
22. C
Heat can increase fentanyl absorption and multiple patches can cause overdose. Drowsiness and slow breathing require urgent assessment for opioid toxicity.
23. A
Amiodarone can cause both hypothyroidism and thyrotoxicosis. Weight loss, tremor, sweating, palpitations and thyroid results indicate thyrotoxicosis requiring review.
24. D
Topical timolol can be systemically absorbed and cause beta-blockade, including bradycardia and bronchospasm. Risk is higher with asthma and concurrent beta-blocker therapy.
25. B
Methadone overdose in children is an emergency because it can cause delayed and prolonged respiratory depression. Hospital assessment is required even if the child is initially awake.
Here are 25 multiple-choice questions designed to mimic the GPHC exam itself. At the bottom of the page you will find answers and rationale for each question.