Prescribing Safety Assessment (PSA) — Questions and Answers

Question 1: What are the main risks of NSAID use?

Only headache
Gastrointestinal bleeding, renal impairment, and cardiovascular events (Correct answer)
No significant risks
Only allergic reactions

Correct answer: Gastrointestinal bleeding, renal impairment, and cardiovascular events

NSAIDs carry risks of GI bleeding/ulceration, kidney damage (especially with dehydration), and increased cardiovascular events with prolonged use.

Question 2: In hepatic impairment, which plasma protein is most significantly reduced, leading to increased free drug fractions of highly protein-bound medications?

Albumin (Correct answer)
Alpha-1 acid glycoprotein
Transferrin
Fibrinogen

Correct answer: Albumin

Albumin, synthesized by the liver, is reduced in hepatic impairment, increasing the free fraction of acidic drugs like phenytoin, warfarin, and furosemide.

Question 3: A patient with known Addison's disease presents in shock with BP 78/50 mmHg, hyponatremia, hyperkalemia, and hypoglycemia. What is the immediate treatment?

Hydrocortisone 100mg IV bolus, then 50–100mg IV every 6–8 hours (Correct answer)
Fludrocortisone 0.1mg PO daily alone
Dexamethasone 4mg IV every 6 hours
Prednisone 60mg PO immediately

Correct answer: Hydrocortisone 100mg IV bolus, then 50–100mg IV every 6–8 hours

Hydrocortisone IV is the treatment for acute adrenal crisis, providing both glucocorticoid and mineralocorticoid activity needed for hemodynamic recovery.

Question 4: A patient receiving gentamicin develops rising serum creatinine and new-onset tinnitus. What do these findings indicate?

Aminoglycoside nephrotoxicity and ototoxicity requiring discontinuation (Correct answer)
Allergic interstitial nephritis from a beta-lactam
Drug-induced hepatitis presenting with renal symptoms
Normal findings expected with antibiotic therapy in the elderly

Correct answer: Aminoglycoside nephrotoxicity and ototoxicity requiring discontinuation

Rising creatinine (nephrotoxicity) and tinnitus (ototoxicity) are classic dose-dependent adverse effects of aminoglycosides and require prompt drug discontinuation.

Question 5: Which anticoagulant is generally preferred for a patient with severe renal impairment (CrCl <15 mL/min) requiring long-term anticoagulation?

Apixaban
Warfarin (Correct answer)
Rivaroxaban
Dabigatran

Correct answer: Warfarin

Direct oral anticoagulants (DOACs) are substantially renally excreted and accumulate dangerously in severe renal impairment; warfarin, being hepatically metabolized, is preferred.

Question 6: Identify three causes of euvolemic hyponatraemia.

Iron deficiency anaemia Thalassaemia Sideroblastic Anaemia
SIADH Psychogenic polydipsia Hypothyroidism (Correct answer)
Fluid loss addison's disease diuretics
Viral infection lymphomas chronic lymphocytic leukemia

Correct answer: SIADH Psychogenic polydipsia Hypothyroidism

Euvolemic hyponatraemia occurs when the body has a normal total body water content but a low sodium concentration. SIADH causes excessive water retention, diluting sodium. Psychogenic polydipsia involves excessive water intake, leading to dilutional hyponatraemia, while severe hypothyroidism can impair free water excretion, contributing to this electrolyte imbalance.

Question 7: Why are opioids prescribed cautiously?

They are always ineffective
Risk of dependence, tolerance, respiratory depression, and constipation (Correct answer)
They cost too much
They only work for headaches

Correct answer: Risk of dependence, tolerance, respiratory depression, and constipation

Opioids carry significant risks including physical dependence, tolerance requiring increasing doses, life-threatening respiratory depression, and universal constipation.

Question 8: What information must be included for controlled substances?

The prescriber's DEA number, the patient's full address, and specific quantity in words and figures (Correct answer)
Only the drug name
No additional requirements beyond standard prescriptions
The pharmacy's license number

Correct answer: The prescriber's DEA number, the patient's full address, and specific quantity in words and figures

Controlled substance prescriptions require additional safeguards including the prescriber's DEA registration, patient's address, and quantity written in both words and numbers.

Question 9: Which of the following drugs requires routine therapeutic drug monitoring (TDM) due to its narrow therapeutic index?

Metformin
Vancomycin (Correct answer)
Amoxicillin
Azithromycin

Correct answer: Vancomycin

Vancomycin has a narrow therapeutic index and requires routine TDM to ensure efficacy and prevent nephrotoxicity.

Question 10: A patient with postherpetic neuralgia has failed a trial of amitriptyline. What is the most appropriate next step?

Tramadol 50 mg QDS
High-dose ibuprofen 600 mg TDS
Codeine 30 mg QDS
Gabapentin or pregabalin (Correct answer)

Correct answer: Gabapentin or pregabalin

Gabapentin and pregabalin are NICE-recommended alternatives for neuropathic pain when first-line agents fail.

Question 11: A patient on long-term methadone maintenance is started on phenytoin for new-onset seizures. What is the anticipated outcome?

Opioid withdrawal symptoms from phenytoin-induced increase in methadone clearance (Correct answer)
Phenytoin toxicity from methadone-mediated CYP2C9 inhibition
Methadone toxicity from decreased hepatic clearance
Serotonin syndrome from combined opioid and anticonvulsant CNS effects

Correct answer: Opioid withdrawal symptoms from phenytoin-induced increase in methadone clearance

Phenytoin is a broad enzyme inducer (CYP3A4, CYP2C9) that significantly accelerates methadone metabolism, precipitating opioid withdrawal in dependent patients.

Question 12: Which IV fluid is most appropriate for a patient with diabetic ketoacidosis (DKA) after initial stabilization?

3% Hypertonic saline
Lactated Ringer's with potassium only
5% Dextrose in water
0.9% Normal saline followed by 0.45% saline with dextrose when glucose falls (Correct answer)

Correct answer: 0.9% Normal saline followed by 0.45% saline with dextrose when glucose falls

In DKA, isotonic saline is used initially; as serum glucose approaches 200 mg/dL, dextrose-containing fluid is added to prevent hypoglycemia while continuing insulin.

Question 13: A patient stabilised on warfarin requires analgesia for headache. Which analgesic should be avoided?

Aspirin 600 mg (Correct answer)
Paracetamol 500 mg
Codeine 30 mg
Gabapentin 100 mg

Correct answer: Aspirin 600 mg

Aspirin inhibits platelet aggregation and can displace warfarin from protein binding, significantly increasing bleeding risk.

Question 14: Which prescription abbreviation is considered most dangerous and should always be written in full to prevent a medication error?

'tab' for tablet
'PO' for by mouth
'mg' for milligrams
'U' for units, which can be misread as a zero causing a tenfold overdose (Correct answer)

Correct answer: 'U' for units, which can be misread as a zero causing a tenfold overdose

Writing 'U' for units is dangerous because it can be misread as '0', turning '10U of insulin' into '100 units' — a potentially fatal tenfold overdose.

Question 15: A patient with chronic alcohol use disorder presents with a generalized tonic-clonic seizure. What is the drug of choice?

Haloperidol 5mg IM
Lorazepam 4mg IV (or diazepam 10mg IV) (Correct answer)
Levetiracetam 1500mg IV
Phenytoin 20mg/kg IV at 50mg/min

Correct answer: Lorazepam 4mg IV (or diazepam 10mg IV)

Benzodiazepines are first-line for alcohol withdrawal seizures because they enhance GABA-A receptor function, the mechanism disrupted by alcohol withdrawal.

Question 16: A 28-week pregnant woman has a blood pressure of 158/98 mmHg. Which antihypertensive is most appropriate?

Ramipril 5mg daily
Lisinopril 10mg daily
Losartan 50mg daily
Labetalol 100mg twice daily (Correct answer)

Correct answer: Labetalol 100mg twice daily

Labetalol is a first-line antihypertensive in pregnancy; ACE inhibitors and ARBs are absolutely contraindicated due to fetotoxicity and teratogenicity, especially in the second and third trimester.

Question 17: A patient on simvastatin 40 mg starts clarithromycin for a chest infection and develops severe myalgia with dark urine. What is the most likely mechanism?

The simvastatin dose was independently too high
Clarithromycin induces CYP3A4, increasing statin conversion to toxic metabolites
Clarithromycin inhibits CYP3A4, raising simvastatin plasma levels (Correct answer)
Clarithromycin directly damages skeletal muscle

Correct answer: Clarithromycin inhibits CYP3A4, raising simvastatin plasma levels

Clarithromycin is a potent CYP3A4 inhibitor that markedly increases simvastatin exposure, precipitating statin-induced myopathy and potentially rhabdomyolysis.

Question 18: Before initiating amiodarone therapy, which baseline investigations are most essential?

Thyroid function tests, liver function tests, and chest X-ray (Correct answer)
Random glucose and HbA1c
Full blood count and ESR only
Renal function and urine dipstick only

Correct answer: Thyroid function tests, liver function tests, and chest X-ray

Amiodarone is iodine-rich and can cause thyroid dysfunction, hepatotoxicity, and pulmonary toxicity, so TFTs, LFTs, and CXR are mandatory at baseline.

Question 19: A prescription for metformin 1000 mg b.i.d. instructs the patient to take the drug how many times per day?

Twice (Correct answer)
Once
Four times
Three times

Correct answer: Twice

'B.i.d.' stands for 'bis in die,' Latin for 'twice a day,' so the patient takes 1000 mg in the morning and 1000 mg in the evening.

Question 20: A patient with severe hepatic impairment requires analgesia for moderate pain. Which approach is most appropriate?

Regular NSAIDs as they avoid hepatic metabolism
Low-dose paracetamol (500mg TDS) with careful monitoring (Correct answer)
Paracetamol at full standard doses (1g QDS)
Codeine at standard dose for reliable conversion to morphine

Correct answer: Low-dose paracetamol (500mg TDS) with careful monitoring

Low-dose paracetamol with monitoring is safer than NSAIDs (GI bleeding and renal risk in cirrhosis) or opioids (risk of precipitating hepatic encephalopathy).

Question 21: A patient with Child-Pugh Class B liver disease is prescribed a drug with a high hepatic extraction ratio administered orally. The most likely pharmacokinetic consequence is:

Increased oral bioavailability due to reduced first-pass metabolism (Correct answer)
No change as hepatic extraction ratio is independent of liver function
Reduced oral bioavailability due to compensatory enzyme induction
Reduced half-life due to increased renal clearance

Correct answer: Increased oral bioavailability due to reduced first-pass metabolism

High hepatic extraction ratio drugs undergo extensive first-pass metabolism; hepatic impairment reduces this extraction, substantially increasing systemic bioavailability.

Question 22: How does unfractionated heparin (UFH) differ from low molecular weight heparin (LMWH) in clinical practice?

UFH is available only as a subcutaneous preparation
UFH requires anti-Xa monitoring in all patients regardless of renal function
UFH can be fully reversed with protamine sulfate and is monitored with APTT (Correct answer)
UFH has a much longer half-life, requiring once-daily dosing

Correct answer: UFH can be fully reversed with protamine sulfate and is monitored with APTT

UFH is monitored using APTT and can be fully reversed with protamine sulfate, unlike LMWH which has only partial protamine reversal and is monitored with anti-Xa levels in select populations.

Question 23: Spironolactone is generally contraindicated in patients with severe renal impairment (eGFR <30 mL/min) primarily due to the risk of:

Refractory hypertension
Life-threatening hyperkalemia (Correct answer)
Metabolic acidosis
Severe hyponatremia

Correct answer: Life-threatening hyperkalemia

Spironolactone blocks aldosterone-mediated potassium excretion; in renal impairment, already-reduced potassium clearance combined with this effect causes dangerous hyperkalemia.

Question 24: A 64-year-old man with gout and hypertension is prescribed bendroflumethiazide. Why is this choice problematic?

Thiazides cause hypertension through sodium retention in these patients
Thiazides reduce LDL cholesterol, interfering with concurrent statin therapy
Thiazides reduce renal uric acid excretion, potentially precipitating gout attacks (Correct answer)
Thiazides are only problematic if the patient also has diabetes

Correct answer: Thiazides reduce renal uric acid excretion, potentially precipitating gout attacks

Thiazide diuretics compete with uric acid for renal tubular secretion, reducing urate excretion and raising serum uric acid levels, which can precipitate or worsen gout.

Question 25: A patient on lithium presents with coarse tremor, vomiting, diarrhea, and confusion. What is the most likely cause?

Serotonin syndrome from an unidentified drug
Severe dehydration alone without drug accumulation
Acute psychosis exacerbation requiring dose increase
Lithium toxicity (Correct answer)

Correct answer: Lithium toxicity

Coarse tremor, GI upset, and neurotoxicity are hallmarks of lithium toxicity requiring urgent assessment and management.

Question 26: Which of the following antihypertensives requires the greatest dose reduction in severe renal impairment compared to normal renal function?

Losartan
Verapamil
Amlodipine
Atenolol (Correct answer)

Correct answer: Atenolol

Atenolol is almost entirely renally excreted unchanged, requiring significant dose reduction to prevent accumulation and bradycardia in renal impairment.

Question 27: Which of the following drugs is LEAST likely to cause QTc interval prolongation?

Amiodarone
Metformin (Correct answer)
Clarithromycin
Haloperidol

Correct answer: Metformin

Metformin does not affect cardiac ion channels; QT-prolonging drugs include macrolide antibiotics, antipsychotics, and antiarrhythmics that block cardiac hERG potassium channels.

Question 28: What is the maximum daily dose of paracetamol for adults?

10 grams
4 grams (4000mg) in divided doses with at least 4 hours between doses (Correct answer)
No maximum exists
1 gram

Correct answer: 4 grams (4000mg) in divided doses with at least 4 hours between doses

The maximum safe dose is 4g daily for healthy adults, with at least 4 hours between doses. Lower maximums apply to elderly patients and those with liver impairment.

Question 29: What is the first-line treatment for anaphylaxis?

Inhaled salbutamol
Intravenous steroids
Intramuscular adrenaline (epinephrine) 0.5mg (1:1000) into the anterolateral thigh (Correct answer)
Oral antihistamines

Correct answer: Intramuscular adrenaline (epinephrine) 0.5mg (1:1000) into the anterolateral thigh

IM adrenaline is the first and most important treatment for anaphylaxis, addressing bronchospasm, hypotension, and angioedema. Delay can be fatal.

Question 30: A patient on isoniazid for tuberculosis develops jaundice and ALT 10 times the upper limit of normal. What pattern of drug-induced liver injury is this?

Drug-induced steatohepatitis
Mixed pattern hepatotoxicity
Hepatocellular hepatotoxicity (Correct answer)
Cholestatic hepatotoxicity

Correct answer: Hepatocellular hepatotoxicity

Isoniazid causes predominantly hepatocellular injury with markedly elevated ALT; it can progress to fulminant hepatic failure if not discontinued promptly upon recognition.

Question 31: A patient develops acute pulmonary edema with severe respiratory distress and an SpO2 of 82%. Which diuretic dose and route provides the fastest relief?

Furosemide 80mg PO
Hydrochlorothiazide 25mg PO
Furosemide 40–80mg IV bolus (Correct answer)
Torsemide 20mg PO

Correct answer: Furosemide 40–80mg IV bolus

IV furosemide provides rapid diuresis and immediate venodilation, making it far superior to oral formulations in acute pulmonary edema.

Question 32: Which drug combination is most likely to cause dangerous QT interval prolongation?

Lisinopril and amlodipine
Amoxicillin and metronidazole
Haloperidol and azithromycin (Correct answer)
Metformin and atorvastatin

Correct answer: Haloperidol and azithromycin

Both haloperidol and azithromycin independently prolong the QT interval; combining them significantly increases the risk of Torsades de Pointes.

Question 33: A patient on warfarin starts rifampicin for tuberculosis. What adjustment to warfarin dosing would most likely be required?

Significant dose increase due to enzyme induction (Correct answer)
Dose reduction by approximately 50% due to enzyme inhibition
Immediate switch to a NOAC due to unpredictable interaction
No change required — rifampicin does not affect warfarin

Correct answer: Significant dose increase due to enzyme induction

Rifampicin is a potent inducer of CYP2C9 and other hepatic enzymes, dramatically accelerating warfarin metabolism and requiring substantial dose increases to maintain therapeutic INR.

Question 34: Stevens-Johnson syndrome is a severe mucocutaneous adverse drug reaction most classically associated with which medication?

Metformin
Amoxicillin
Standard-dose ibuprofen
Carbamazepine (Correct answer)

Correct answer: Carbamazepine

Carbamazepine and other aromatic anticonvulsants, along with allopurinol and sulfonamides, are strongly associated with Stevens-Johnson syndrome and toxic epidermal necrolysis.

Question 35: What are the most usual side effects of Phenytoin?

Ataxia, peripheral neuropathy, gum hyperplasia, hepatotoxicity (Correct answer)
Rash, rarely stevens-johnson syndrome
Rash, dysarthria, ataxia, nystagmus, ⇓na
Fatigue, mood disorders and agitation

Correct answer: Ataxia, peripheral neuropathy, gum hyperplasia, hepatotoxicity

The most usual side effects of Phenytoin include ataxia (impaired coordination), peripheral neuropathy (nerve damage), gum hyperplasia (overgrowth of gum tissue), and hepatotoxicity (liver damage). These are classic and well-recognized adverse effects associated with long-term phenytoin use, requiring careful monitoring and patient education.

Question 36: A patient with severe hepatic impairment (Child-Pugh C) develops a DVT. Which anticoagulant is most appropriate?

Low molecular weight heparin (Correct answer)
Dabigatran
Apixaban
Rivaroxaban

Correct answer: Low molecular weight heparin

LMWH is preferred in severe hepatic impairment because direct oral anticoagulants undergo significant hepatic metabolism and are generally contraindicated in this setting.

Question 37: What is the WHO analgesic ladder?

A single drug protocol
A surgical pain treatment
A physical therapy exercise
A stepped approach to pain management: Step 1 (non-opioids), Step 2 (weak opioids), Step 3 (strong opioids) (Correct answer)

Correct answer: A stepped approach to pain management: Step 1 (non-opioids), Step 2 (weak opioids), Step 3 (strong opioids)

The WHO ladder provides a systematic approach to pain management, starting with simple analgesics and progressing to stronger options based on pain severity and response.

Question 38: A patient with eGFR of 20 mL/min/1.73m² requires anticoagulation. Which drug does NOT require renal dose adjustment?

Enoxaparin (low molecular weight heparin)
Warfarin (vitamin K antagonist) (Correct answer)
Dabigatran (direct thrombin inhibitor)
Apixaban (factor Xa inhibitor)

Correct answer: Warfarin (vitamin K antagonist)

Warfarin is hepatically metabolized via CYP2C9 and does not require renal dose adjustment, unlike DOACs and LMWH which undergo significant renal clearance.

Question 39: The abbreviation 'p.r.n.' on a prescription means the medication should be taken:

By rectal route
Per renal function
As needed (Correct answer)
Before noon

Correct answer: As needed

'P.r.n.' stands for 'pro re nata,' meaning 'as needed,' and indicates the medication is taken only when required rather than on a scheduled basis.

Question 40: Which of the following best describes why TDM for tacrolimus uses whole blood rather than serum?

Serum processing destroys tacrolimus
Tacrolimus is unstable in serum at room temperature
Tacrolimus concentrates extensively in red blood cells (Correct answer)
Tacrolimus is not detectable in serum

Correct answer: Tacrolimus concentrates extensively in red blood cells

Tacrolimus binds extensively to erythrocytes, making whole blood the appropriate matrix for accurate TDM.

Question 41: A patient on sertraline and tramadol develops hyperthermia (41.2°C), clonus, hyperreflexia, and agitation 2 hours after a tramadol dose increase. What is the diagnosis and management?

Anticholinergic toxidrome — physostigmine 2mg IV
Serotonin syndrome — stop serotonergic agents, cyproheptadine PO/NG, IV benzodiazepines, active cooling (Correct answer)
Neuroleptic malignant syndrome — dantrolene IV and bromocriptine PO
Malignant hyperthermia — dantrolene 2.5mg/kg IV

Correct answer: Serotonin syndrome — stop serotonergic agents, cyproheptadine PO/NG, IV benzodiazepines, active cooling

Serotonin syndrome from combined serotonergic drugs presents with the Hunter triad (clonus, hyperreflexia, hyperthermia) and is treated with cyproheptadine and benzodiazepines.

Question 42: A patient on theophylline for COPD has a level of 22 mcg/mL (therapeutic 10–20 mcg/mL). Which symptom is most consistent with theophylline toxicity?

Hypotension
Hypoglycemia
Seizures (Correct answer)
Bradycardia

Correct answer: Seizures

Theophylline toxicity can cause seizures, tachycardia, and arrhythmias, with seizures being a serious manifestation at supratherapeutic levels.

Question 43: What does the Latin abbreviation 'sig' on a prescription indicate?

Directions for the patient (Correct answer)
The dispensing quantity
The prescriber's signature block
The drug's generic name

Correct answer: Directions for the patient

'Sig' (signatura) means 'write' or 'label' and introduces the directions the pharmacist should place on the medication label for the patient.

Question 44: Under the UK Pregnancy Prevention Programme, what is the minimum mandatory precaution before prescribing sodium valproate to a woman of childbearing potential?

High-dose folic acid supplementation alone
Avoidance of alcohol and enzyme-inducing drugs
Effective contraception and annual specialist review (Correct answer)
Monthly liver function tests throughout treatment

Correct answer: Effective contraception and annual specialist review

The MHRA PPP mandates that valproate is only prescribed to women of childbearing potential if they use effective contraception and undergo annual specialist review acknowledging the risks.

Question 45: A patient on digoxin 125 mcg daily starts amiodarone for atrial fibrillation. Which mechanism best explains the increased digoxin toxicity risk?

Amiodarone induces renal CYP3A4, producing toxic digoxin metabolites
Amiodarone inhibits P-glycoprotein, reducing renal and biliary digoxin elimination (Correct answer)
Pharmacodynamic synergism at the Na+/K+-ATPase pump doubles the inotropic effect
Amiodarone displaces digoxin from tissue binding sites, increasing free levels

Correct answer: Amiodarone inhibits P-glycoprotein, reducing renal and biliary digoxin elimination

Amiodarone inhibits P-glycoprotein-mediated secretion of digoxin in the kidney and bile duct, causing plasma digoxin concentrations to approximately double.

Question 46: A patient with a documented penicillin allergy (rash) requires a beta-lactam antibiotic for a serious infection. What is the safest approach?

All beta-lactams are absolutely contraindicated in any penicillin allergy
Carbapenems have the highest cross-reactivity with penicillins and must be avoided
Penicillin allergy means only monobactams and vancomycin can be used
Cross-reactivity between penicillins and cephalosporins is primarily due to the R1 side chain; structural dissimilarity makes most cephalosporins safe (Correct answer)

Correct answer: Cross-reactivity between penicillins and cephalosporins is primarily due to the R1 side chain; structural dissimilarity makes most cephalosporins safe

Cross-reactivity between penicillins and cephalosporins is due to similar R1 side chains; for non-anaphylactic penicillin allergy, structurally dissimilar cephalosporins can often be used safely.

Question 47: What fluids should be prescribed for high calcium levels?

Nacl over 20 hours with no potassium
Nacl over 1 hours with no potassium
Nacl over 96 hours with no potassium
NaCl over 4 hours with no potassium (Correct answer)

Correct answer: NaCl over 4 hours with no potassium

For hypercalcemia, intravenous normal saline (0.9% NaCl) is the initial treatment of choice to promote renal calcium excretion and correct dehydration. Administering it over 4 hours helps rehydrate the patient and dilute serum calcium. Potassium is typically omitted unless there is a known deficiency, as hypercalcemia itself can sometimes be associated with hypokalemia.

Question 48: Which condition would most likely increase cyclosporine blood levels and require downward dose adjustment?

Increased physical activity
Co-administration of rifampin
Co-administration of fluconazole (Correct answer)
High-fiber diet

Correct answer: Co-administration of fluconazole

Fluconazole inhibits CYP3A4, reducing cyclosporine metabolism and increasing blood levels, necessitating dose reduction.

Question 49: What is a pain assessment tool and why is it important?

A type of medication
A standardized method for measuring pain intensity to guide treatment decisions and monitor response (Correct answer)
Only useful for children
A surgical instrument

Correct answer: A standardized method for measuring pain intensity to guide treatment decisions and monitor response

Pain assessment tools (like the numeric rating scale 0-10) provide consistent measurement, enabling appropriate treatment selection and monitoring of response.

Question 50: Under the 2015 FDA Pregnancy and Lactation Labeling Rule (PLLR), the old letter-category system (A/B/C/D/X) was replaced. What do the new labeling sections require?

Only a black box warning if any risk is identified
Narrative summaries of human and animal data for pregnancy, lactation, and reproductive potential (Correct answer)
Color-coded risk tiers (green/yellow/red) standardized across all drugs
A single pregnancy risk score from 0 to 10

Correct answer: Narrative summaries of human and animal data for pregnancy, lactation, and reproductive potential

The PLLR requires narrative text describing available human and animal data about risks in the subsections for Pregnancy, Lactation, and Females and Males of Reproductive Potential, replacing the simple A-X letter grades.

Question 51: Which route of administration most reliably bypasses hepatic first-pass metabolism?

Oral tablet
Enteric-coated capsule
Sublingual tablet (Correct answer)
Modified-release oral formulation

Correct answer: Sublingual tablet

Sublingual administration allows drug absorption directly into systemic circulation via the sublingual veins, bypassing the portal circulation and hepatic first-pass effect.

Question 52: A patient starts rituximab infusion and develops fever, rigors, and bronchospasm within the first hour. What is the most likely cause?

Sepsis unmasked by rituximab-induced immunosuppression
Cytokine release from rituximab binding CD20 on circulating B cells (Correct answer)
Direct complement activation by rituximab
IgE-mediated anaphylaxis to murine antibody components

Correct answer: Cytokine release from rituximab binding CD20 on circulating B cells

Rituximab binds CD20 on circulating B cells triggering cytokine release; this infusion reaction is most severe during the first infusion when circulating B-cell burden is highest.

Question 53: Omeprazole co-prescription reduces the antiplatelet efficacy of clopidogrel. What is the mechanism?

CYP2C19 inhibition by omeprazole reduces conversion of clopidogrel to its active thiol metabolite (Correct answer)
Pharmacodynamic competition at platelet P2Y12 receptors
Omeprazole induces P-glycoprotein efflux of clopidogrel from enterocytes
Alkaline gastric pH from omeprazole reduces clopidogrel dissolution and absorption

Correct answer: CYP2C19 inhibition by omeprazole reduces conversion of clopidogrel to its active thiol metabolite

Clopidogrel is a prodrug requiring CYP2C19 for bioactivation; omeprazole inhibits this enzyme, reducing formation of the active metabolite and diminishing platelet P2Y12 inhibition.

Question 54: During general anesthesia, a patient develops rapidly rising end-tidal CO2, generalized muscle rigidity, and temperature of 41.8°C. What is the specific antidote?

Ice packs and acetaminophen 1g IV for fever control
Succinylcholine 1.5mg/kg IV to induce relaxation
Dantrolene 2.5mg/kg IV bolus, repeatable every 5 minutes up to 10mg/kg total (Correct answer)
Propofol infusion to deepen anesthesia

Correct answer: Dantrolene 2.5mg/kg IV bolus, repeatable every 5 minutes up to 10mg/kg total

Dantrolene is the specific antidote for malignant hyperthermia, inhibiting ryanodine receptor-mediated calcium release from the sarcoplasmic reticulum.

Question 55: A patient with eGFR 15 ml/min requires opioid analgesia for cancer pain. Which opioid is most appropriate?

Tramadol
Codeine
Morphine
Fentanyl (Correct answer)

Correct answer: Fentanyl

Fentanyl is preferred in severe renal impairment because its metabolites are not renally excreted and do not accumulate to cause toxicity.

Question 56: Which of the following best describes the goal of area under the curve (AUC)-guided vancomycin dosing compared to traditional trough-only monitoring?

AUC dosing simplifies monitoring by requiring fewer blood draws
AUC dosing eliminates the need for renal function monitoring
AUC dosing is only used in pediatric patients
AUC dosing better balances efficacy and nephrotoxicity risk (Correct answer)

Correct answer: AUC dosing better balances efficacy and nephrotoxicity risk

AUC-guided dosing optimizes the AUC/MIC ratio for efficacy while minimizing nephrotoxicity risk compared to trough-only monitoring.

Question 57: A patient has a hypertensive emergency (BP 230/140 mmHg) with acute pulmonary edema. Which agent provides the safest, most titratable blood pressure reduction?

Oral labetalol 200mg
Sublingual nifedipine 10mg
Lisinopril 10mg PO
Nicardipine IV infusion starting at 5mg/hr (Correct answer)

Correct answer: Nicardipine IV infusion starting at 5mg/hr

IV nicardipine infusion allows precise, titratable blood pressure reduction essential in hypertensive emergencies with end-organ damage.

Question 58: A 3-year-old (15kg) with febrile seizure has been seizing for 7 minutes at home. Parents have diazepam rectal gel (Diastat). What is the correct dose?

0.2mg/kg IV push (3mg)
0.1mg/kg rectally (1.5mg)
10mg rectally regardless of weight
0.5mg/kg rectally (7.5mg) (Correct answer)

Correct answer: 0.5mg/kg rectally (7.5mg)

Rectal diazepam (Diastat) dose for children aged 2–5 years is 0.5mg/kg, providing rapid absorption without IV access.

Question 59: A patient on oral morphine 30 mg twice daily is switched to oral oxycodone. What is the approximate equianalgesic oxycodone dose?

45 mg twice daily
30 mg twice daily
20 mg twice daily (Correct answer)
60 mg twice daily

Correct answer: 20 mg twice daily

Oral oxycodone is approximately 1.5 times more potent than oral morphine, so 60 mg/day morphine equates to approximately 40 mg/day (20 mg BD) oxycodone.

Question 60: A patient on phenytoin has a total level of 8 mcg/mL (therapeutic 10–20 mcg/mL) but appears clinically stable. Their albumin is 2.0 g/dL. What should you consider?

Discontinue phenytoin
Switch to levetiracetam without further testing
Increase phenytoin dose immediately
Check free phenytoin level before adjusting (Correct answer)

Correct answer: Check free phenytoin level before adjusting

Phenytoin is highly protein-bound; low albumin increases the free fraction, so a corrected or free phenytoin level is needed before adjusting the dose.

Question 61: What is the maximum recommended rate of IV potassium infusion via a peripheral line to minimize risk of phlebitis and cardiac toxicity?

20 mEq/hour
40 mEq/hour
5 mEq/hour
10 mEq/hour (Correct answer)

Correct answer: 10 mEq/hour

Peripheral IV potassium should not exceed 10 mEq/hour to minimize the risk of vein irritation and potentially fatal cardiac arrhythmias.

Question 62: What is serotonin syndrome?

A mild headache from antidepressants
A withdrawal symptom
An allergic reaction
A potentially life-threatening condition caused by excessive serotonin, often from combining serotonergic drugs (Correct answer)

Correct answer: A potentially life-threatening condition caused by excessive serotonin, often from combining serotonergic drugs

Serotonin syndrome results from excessive serotonergic activity, caused by combining drugs like SSRIs with MAOIs, tramadol, or triptans. Symptoms include agitation, hyperthermia, and clonus.

Prescribing Safety Assessment (PSA)

The PSA is a UK national exam for final-year medical students that assesses safe and effective prescribing skills across eight domains. It is jointly owned by the Medical Schools Council and NHS England and must be passed to progress to foundation training.

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120 min

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