Which anti-emetic is strictly contraindicated in complete Bowel Obstruction and in Parkinson's disease?

Metoclopramide (and Domperidone in Parkinson's is safer as it does not cross the blood-brain barrier, though MHRA restricts domperidone due to QT prolongation)—Metoclopramide is a prokinetic dopamine D2 antagonist that crosses the BBB (worsening Parkinsonism/causing acute dystonia) and increases peristalsis against mechanical bowel obstruction (use Cyclizine or Haloperidol/Octreotide instead).

What baseline and ongoing monitoring is required by the BNF for Amiodarone therapy, and why does it cause both hypo- and hyperthyroidism?

Baseline TFTs, LFTs, U&Es, ECG, and Chest X-ray, then TFTs and LFTs every 6 months. Amiodarone contains ~37% iodine by weight and structurally resembles thyroxine: it can cause iodine-induced hypothyroidism (Wolff-Chaikoff effect) or thyrotoxicosis (Type 1 Jod-Basedow or Type 2 destructive thyroiditis), plus pulmonary fibrosis, corneal microdeposits, and slate-grey skin.

What are the Kings College Hospital criteria indicating the need for urgent Liver Transplantation referral after Paracetamol overdose?

Arterial pH 100 seconds (INR >6.5), Serum Creatinine >300 µmol/L, and Grade III or IV hepatic encephalopathy.

In Paracetamol overdose, how does the clinical management differ if the patient presents <4 hours vs. 4–15 hours vs. staggered overdose?

Give oral Activated Charcoal if presenting within 1 hour of >150 mg/kg ingestion. For single acute overdose, take plasma paracetamol level at 4 hours post-ingestion (not earlier) and plot on the treatment nomogram to decide on IV Acetylcysteine (NAC). For staggered overdose or presentation >8 hours after large ingestion, start IV NAC immediately without waiting for levels.

How do you calculate the Anion Gap in metabolic acidosis, and what causes a High Anion Gap vs. Normal Anion Gap Metabolic Acidosis?

Anion Gap = (Na+ + K+) - (Cl- + HCO3-), normal 10–18 mmol/L. High Anion Gap ('MUDPILES' / 'KULT'): Ketoacidosis (DKA, starvation, alcoholic), Uraemia, Lactic acidosis, Toxins (salicylates, methanol, ethylene glycol). Normal Anion Gap (Hyperchloraemic—'ABCD'): Addison's, Bicarbonate loss (diarrhoea, ileostomy), Chloride infusion (0.9% NaCl), Diuretics (acetazolamide) / Renal Tubular Acidosis.

Why must Oral Bisphosphonates (e.g., Alendronic Acid 70 mg weekly) be taken with strict administration instructions?

To prevent severe erosive oesophagitis and ensure absorption: take on an empty stomach at least 30 minutes before breakfast/other drugs with a full glass of plain tap water, and remain sitting or standing upright for at least 30 minutes afterwards; also perform dental check before starting due to Osteonecrosis of the Jaw (ONJ) risk.

What screening tests must be completed before starting a Biologic anti-TNF-alpha therapy (e.g., Infliximab, Adalimumab)?

Screen for latent and active Tuberculosis (Chest X-ray + Interferon-Gamma Release Assay / Mantoux test), plus Hepatitis B, Hepatitis C, and HIV serology.

How do you manage Warfarin over-anticoagulation based on INR and bleeding status per BNF/BSH guidelines?

Major bleeding (any INR): stop warfarin, give IV 4-factor Prothrombin Complex Concentrate (PCC / Beriplex) + IV Phytomenadione (Vitamin K1) 5 mg. INR >8.0 with minor bleeding: stop warfarin, give IV Vitamin K 1–3 mg. INR >8.0 with NO bleeding: stop warfarin, give oral Vitamin K 1–5 mg. INR 5.0–8.0 with NO bleeding: withhold 1–2 doses and reduce maintenance dose.

Match each poisoning/overdose to its specific BNF antidote: 1) Opioids, 2) Benzodiazepines, 3) Beta-blockers, 4) Digoxin, 5) Organophosphates, 6) Iron, 7) Cyanide, 8) Dabigatran, 9) Apixaban/Rivaroxaban.

1) Naloxone, 2) Flumazenil (rarely used—risk of seizures), 3) High-dose IV Glucagon (after atropine), 4) Digoxin-specific antibody fragments (DigiFab), 5) Atropine + Pralidoxime, 6) Desferrioxamine, 7) Hydroxocobalamin (or sodium thiosulfate/nitrite), 8) Idarucizumab, 9) Andexanet alfa.

What electrolyte disturbance strongly predisposes patients to Digoxin toxicity, and what are its classic clinical features?

Hypokalaemia (digoxin competes with K+ at the cardiac Na+/K+-ATPase pump—hence loop/thiazide diuretics precipitate toxicity); features include nausea, anorexia, confusion, xanthopsia (yellow-green halos), and bradyarrhythmias / 'reverse tick' ST depression.

In MRCP Part 1 Immunology, classify the 4 Gell and Coombs Hypersensitivity Reactions with one classic clinical example of each.

Type I (Immediate IgE-mediated mast cell degranulation): Anaphylaxis, allergic asthma. Type II (Cytotoxic IgG/IgM antibody against cell-surface antigen): Goodpasture's, autoimmune haemolytic anaemia, Graves' disease. Type III (Immune complex deposition): SLE, post-streptococcal glomerulonephritis, serum sickness. Type IV (Delayed T-cell mediated): Allergic contact dermatitis, Mantoux test, MS.

When converting oral Morphine Sulfate to subcutaneous Morphine or subcutaneous Diamorphine in Palliative Care (BNF), what are the exact conversion ratios?

Oral Morphine to Subcutaneous Morphine = divide by 2 (2:1 ratio, e.g., 60 mg/24h oral morphine = 30 mg/24h SC morphine). Oral Morphine to Subcutaneous Diamorphine = divide by 3 (3:1 ratio, e.g., 60 mg/24h oral morphine = 20 mg/24h SC diamorphine).

In MRCP Part 1 Renal Physiology, list the exact tubular site of action and electrolyte signature of: 1) Acetazolamide, 2) Furosemide, 3) Bendroflumethiazide, 4) Spironolactone/Amiloride.

1) Acetazolamide: Proximal Convoluted Tubule (carbonic anhydrase inhibitor → normal anion gap metabolic acidosis). 2) Furosemide: Thick Ascending Loop of Henle (inhibits NKCC2 → hypokalaemia, hyponatraemia, hypocalcaemia, ototoxicity). 3) Thiazides: Distal Convoluted Tubule (inhibits NCC → hyponatraemia, hypokalaemia, HYPERcalcaemia, hyperuricaemia). 4) Spironolactone/Amiloride: Cortical Collecting Duct (aldosterone antagonist / ENaC blocker → hyperkalaemia).

What clinical factors precipitate Lithium toxicity (>1.5 mmol/L), and how does coarse tremor differ from fine tremor?

Precipitated by dehydration, hyponatraemia/low-salt diet, and 'DAMN' drugs (thiazide diuretics, ACE inhibitors/ARBs, NSAIDs, metronidazole). Fine tremor is a benign side effect at therapeutic levels; coarse tremor, ataxia, dysarthria, nystagmus, and confusion indicate acute toxicity.

What is the MHRA warning regarding Fluoroquinolone antibiotics (Ciprofloxacin, Levofloxacin)?

Restrict use to severe infections where other antibiotics are inappropriate due to risks of disabling, potentially irreversible Tendonitis / Achilles Tendon Rupture (especially in patients >60, renal impairment, or co-prescribed corticosteroids), aortic aneurysm/dissection, peripheral neuropathy, and Clostridioides difficile infection.

What is the BNF rule regarding Clarithromycin (or Erythromycin) in a patient taking Simvastatin or Atorvastatin?

Withhold the statin while taking the course of Clarithromycin/Erythromycin because CYP3A4 inhibition markedly increases statin levels, risking severe myopathy and rhabdomyolysis.

In MRCP Part 1 Genetics, if both parents are asymptomatic carriers of an Autosomal Recessive condition (e.g., Cystic Fibrosis), what is the probability that an unaffected sibling of an affected child is a carrier?

2/3 (67%)—because the homozygous affected genotype (aa, 1/4) is already excluded once we know the sibling is phenotypically unaffected, leaving AA (1/3) and 2 Aa (2/3).

What is the BNF warning regarding co-prescribing Trimethoprim (or Co-trimoxazole) in a patient taking Methotrexate?

Strictly avoid—both are folate antagonists (dihydrofolate reductase inhibitors), and co-administration causes life-threatening pancytopenia/bone marrow aplasia.

What is the BNF rule for perioperative management of SGLT2 inhibitors (dapagliflozin, empagliflozin, canagliflozin) before major surgery or during acute illness?

Omit SGLT2 inhibitors the day before / during major surgery and during acute dehydrating illness because they can precipitate Euglycaemic Diabetic Ketoacidosis (ketones ≥3.0 mmol/L and acidosis despite normal/near-normal blood glucose <11 mmol/L).

In Clostridioides difficile (C. diff) infection, what is the NICE NG199 first-line and second-line antibiotic treatment?

First-line for a first episode (mild, moderate, or severe): Oral Vancomycin 125 mg QDS for 10 days. Second-line (or relapse within 12 weeks): Oral Fidaxomicin 200 mg BD for 10 days (Oral Metronidazole is NO LONGER first-line in NICE guidelines).

In MRCP Part 1 Cardiology, link the classic Jugular Venous Pulse (JVP) waveform abnormality to its pathology: 1) Cannon 'a' waves, 2) Giant 'v' waves, 3) Absent 'a' waves, 4) Kussmaul's sign (steep x & y descents).

1) Cannon 'a' waves: Complete (3rd-degree) heart block or VT (atria contracting against a closed tricuspid valve). 2) Giant 'v' waves: Tricuspid regurgitation. 3) Absent 'a' waves: Atrial fibrillation. 4) Steep x & y descents + Kussmaul's sign (JVP rises on inspiration): Constrictive pericarditis.

According to the BNF, what is the therapeutic serum concentration range for Lithium, when should blood samples be taken, and how often is maintenance monitoring required?

Target range: 0.4–1.0 mmol/L (0.8–1.0 mmol/L for acute manic relapse). Sample taken strictly 12 hours post-dose. Check levels weekly after initiation/dose change until stable, then every 3 months for the first year (6-monthly thereafter unless high risk), plus eGFR, TFTs, and calcium every 6 months.

Before starting Azathioprine or 6-Mercaptopurine for Inflammatory Bowel Disease, which enzyme activity must be checked to prevent fatal myelosuppression?

Thiopurine Methyltransferase (TPMT) activity; also avoid co-prescribing Allopurinol (xanthine oxidase inhibitor) as it blocks azathioprine breakdown and causes severe bone marrow suppression.

What is the classic acid-base disturbance in Salicylate (Aspirin) overdose, and when is urinary alkalinization or haemodialysis indicated?

Mixed respiratory alkalosis (direct stimulation of respiratory centre causing hyperventilation) and high anion gap metabolic acidosis (uncoupling of oxidative phosphorylation). Treat with IV Sodium Bicarbonate (urinary alkalinization enhances salicylate excretion) or Haemodialysis if serum salicylate >700 mg/L (or severe acidosis/renal failure/pulmonary oedema).

What is the most common adverse reaction to IV Acetylcysteine (NAC) in Paracetamol overdose, and how is it managed?

Anaphylactoid reaction (flushing, urticaria, wheeze, angioedema mediated by histamine release, NOT IgE): temporarily pause or slow the infusion, give chlorphenamine/nebulized salbutamol if needed, and restart NAC once settled.

Which classic drugs are potent Cytochrome P450 Inducers ('CRAP GPS') vs. Inhibitors ('SICKFACES.COM') that alter Warfarin INR?

Inducers (LOWER INR, reduce warfarin effect): Carbamazepine, Rifampicin, Alcohol (chronic), Phenytoin, Griseofulvin, Phenobarbital, St John's Wort. Inhibitors (RAISE INR, increase bleeding risk): Sodium valproate, Isoniazid, Cimetidine, Ketoconazole/Fluconazole, Erythromycin/Clarithromycin, Sulfonamides, Ciprofloxacin, Omeprazole, Metronidazole, Amiodarone, acute Alcohol, Cranberry/Grapefruit juice.

What is the specific antidote for severe Methotrexate toxicity or accidental daily overdose?

Folinic acid (Calcium leucovorin)—NOT folic acid—given IV immediately to bypass dihydrofolate reductase inhibition.

Which medications are well-known causes of Drug-Induced QT Interval Prolongation (risk of Torsades de Pointes—treat with IV Magnesium Sulfate 2 g)?

Macrolides (clarithromycin, erythromycin), Fluoroquinolones (ciprofloxacin, levofloxacin), SSRIs (especially Citalopram/Escitalopram), Tricyclic antidepressants, Antipsychotics (haloperidol, quetiapine), Ondansetron, Domperidone, Amiodarone, and Sotalol.

In Palliative Care opioid prescribing, how is the breakthrough PRN dose calculated from the total 24-hour background opioid dose?

One-sixth (1/6th) to one-tenth (1/10th) of the total 24-hour regular opioid dose, given every 2–4 hours as required, always co-prescribed with a regular laxative (senna/macrogol).

According to BNF guidelines, how must oral Methotrexate always be prescribed and monitored?

Prescribed strictly ONCE WEEKLY (never daily—specify the day of the week on the prescription) alongside Folic Acid 5 mg weekly on a different day. Monitor FBC, U&Es, and LFTs before starting, every 1–2 weeks until stable, then every 2–3 months.

In Gentamicin once-daily (Hartford) dosing, what are the two major organ toxicities, which neuromuscular disease is an absolute contraindication, and what is monitored?

Nephrotoxicity and irreversible Ototoxicity (vestibulocochlear nerve—screen for MT-RNR1 gene if possible). Contraindicated in Myasthenia Gravis. Monitor serum gentamicin levels (6–14h post-dose on Hartford nomogram or trough <1 mg/L) and daily renal function.

Which strong opioid transdermal patch or subcutaneous drug is safest in severe Renal Impairment / End-Stage Renal Failure (eGFR <15 mL/min)?

Fentanyl, Alfentanil, or Buprenorphine (metabolized by the liver with no active renally excreted metabolites; Morphine and Codeine accumulate neurotoxic morphine-6-glucuronide in renal failure).

BNF High-Yield Prescribing & MRCP Part 1 Clinical Sciences: Drug Monitoring (Lithium, Warfarin, Methotrexate, Gentamicin), Antidotes & P450

High-yield British National Formulary (BNF) safe prescribing rules, therapeutic drug monitoring (TDM), emergency toxicology antidotes, cytochrome P450 interactions, and MRCP Part 1 basic clinical sciences.

Level: advanced
Languages: en → en
Cards: 32
Markdown: BNF High-Yield Prescribing & MRCP Part 1 Clinical Sciences: Drug Monitoring (Lithium, Warfarin, Methotrexate, Gentamicin), Antidotes & P450 (.md)

Flashcards (32)

#	Front (Term / Question)	Back (Definition / Answer)
1	Which anti-emetic is strictly contraindicated in complete Bowel Obstruction and in Parkinson's disease?	Metoclopramide (and Domperidone in Parkinson's is safer as it does not cross the blood-brain barrier, though MHRA restricts domperidone due to QT prolongation)—Metoclopramide is a prokinetic dopamine D2 antagonist that crosses the BBB (worsening Parkinsonism/causing acute dystonia) and increases peristalsis against mechanical bowel obstruction (use Cyclizine or Haloperidol/Octreotide instead).
2	What baseline and ongoing monitoring is required by the BNF for Amiodarone therapy, and why does it cause both hypo- and hyperthyroidism?	Baseline TFTs, LFTs, U&Es, ECG, and Chest X-ray, then TFTs and LFTs every 6 months. Amiodarone contains ~37% iodine by weight and structurally resembles thyroxine: it can cause iodine-induced hypothyroidism (Wolff-Chaikoff effect) or thyrotoxicosis (Type 1 Jod-Basedow or Type 2 destructive thyroiditis), plus pulmonary fibrosis, corneal microdeposits, and slate-grey skin.
3	What are the Kings College Hospital criteria indicating the need for urgent Liver Transplantation referral after Paracetamol overdose?	Arterial pH <7.30 at 24 hours after ingestion (after fluid resuscitation), OR all three of: Prothrombin Time >100 seconds (INR >6.5), Serum Creatinine >300 µmol/L, and Grade III or IV hepatic encephalopathy.
4	In Paracetamol overdose, how does the clinical management differ if the patient presents <4 hours vs. 4–15 hours vs. staggered overdose?	Give oral Activated Charcoal if presenting within 1 hour of >150 mg/kg ingestion. For single acute overdose, take plasma paracetamol level at 4 hours post-ingestion (not earlier) and plot on the treatment nomogram to decide on IV Acetylcysteine (NAC). For staggered overdose or presentation >8 hours after large ingestion, start IV NAC immediately without waiting for levels.
5	How do you calculate the Anion Gap in metabolic acidosis, and what causes a High Anion Gap vs. Normal Anion Gap Metabolic Acidosis?	Anion Gap = (Na+ + K+) - (Cl- + HCO3-), normal 10–18 mmol/L. High Anion Gap ('MUDPILES' / 'KULT'): Ketoacidosis (DKA, starvation, alcoholic), Uraemia, Lactic acidosis, Toxins (salicylates, methanol, ethylene glycol). Normal Anion Gap (Hyperchloraemic—'ABCD'): Addison's, Bicarbonate loss (diarrhoea, ileostomy), Chloride infusion (0.9% NaCl), Diuretics (acetazolamide) / Renal Tubular Acidosis.
6	Why must Oral Bisphosphonates (e.g., Alendronic Acid 70 mg weekly) be taken with strict administration instructions?	To prevent severe erosive oesophagitis and ensure absorption: take on an empty stomach at least 30 minutes before breakfast/other drugs with a full glass of plain tap water, and remain sitting or standing upright for at least 30 minutes afterwards; also perform dental check before starting due to Osteonecrosis of the Jaw (ONJ) risk.
7	What screening tests must be completed before starting a Biologic anti-TNF-alpha therapy (e.g., Infliximab, Adalimumab)?	Screen for latent and active Tuberculosis (Chest X-ray + Interferon-Gamma Release Assay / Mantoux test), plus Hepatitis B, Hepatitis C, and HIV serology.
8	How do you manage Warfarin over-anticoagulation based on INR and bleeding status per BNF/BSH guidelines?	Major bleeding (any INR): stop warfarin, give IV 4-factor Prothrombin Complex Concentrate (PCC / Beriplex) + IV Phytomenadione (Vitamin K1) 5 mg. INR >8.0 with minor bleeding: stop warfarin, give IV Vitamin K 1–3 mg. INR >8.0 with NO bleeding: stop warfarin, give oral Vitamin K 1–5 mg. INR 5.0–8.0 with NO bleeding: withhold 1–2 doses and reduce maintenance dose.
9	Match each poisoning/overdose to its specific BNF antidote: 1) Opioids, 2) Benzodiazepines, 3) Beta-blockers, 4) Digoxin, 5) Organophosphates, 6) Iron, 7) Cyanide, 8) Dabigatran, 9) Apixaban/Rivaroxaban.	1) Naloxone, 2) Flumazenil (rarely used—risk of seizures), 3) High-dose IV Glucagon (after atropine), 4) Digoxin-specific antibody fragments (DigiFab), 5) Atropine + Pralidoxime, 6) Desferrioxamine, 7) Hydroxocobalamin (or sodium thiosulfate/nitrite), 8) Idarucizumab, 9) Andexanet alfa.
10	What electrolyte disturbance strongly predisposes patients to Digoxin toxicity, and what are its classic clinical features?	Hypokalaemia (digoxin competes with K+ at the cardiac Na+/K+-ATPase pump—hence loop/thiazide diuretics precipitate toxicity); features include nausea, anorexia, confusion, xanthopsia (yellow-green halos), and bradyarrhythmias / 'reverse tick' ST depression.
11	In MRCP Part 1 Immunology, classify the 4 Gell and Coombs Hypersensitivity Reactions with one classic clinical example of each.	Type I (Immediate IgE-mediated mast cell degranulation): Anaphylaxis, allergic asthma. Type II (Cytotoxic IgG/IgM antibody against cell-surface antigen): Goodpasture's, autoimmune haemolytic anaemia, Graves' disease. Type III (Immune complex deposition): SLE, post-streptococcal glomerulonephritis, serum sickness. Type IV (Delayed T-cell mediated): Allergic contact dermatitis, Mantoux test, MS.
12	When converting oral Morphine Sulfate to subcutaneous Morphine or subcutaneous Diamorphine in Palliative Care (BNF), what are the exact conversion ratios?	Oral Morphine to Subcutaneous Morphine = divide by 2 (2:1 ratio, e.g., 60 mg/24h oral morphine = 30 mg/24h SC morphine). Oral Morphine to Subcutaneous Diamorphine = divide by 3 (3:1 ratio, e.g., 60 mg/24h oral morphine = 20 mg/24h SC diamorphine).
13	In MRCP Part 1 Renal Physiology, list the exact tubular site of action and electrolyte signature of: 1) Acetazolamide, 2) Furosemide, 3) Bendroflumethiazide, 4) Spironolactone/Amiloride.	1) Acetazolamide: Proximal Convoluted Tubule (carbonic anhydrase inhibitor → normal anion gap metabolic acidosis). 2) Furosemide: Thick Ascending Loop of Henle (inhibits NKCC2 → hypokalaemia, hyponatraemia, hypocalcaemia, ototoxicity). 3) Thiazides: Distal Convoluted Tubule (inhibits NCC → hyponatraemia, hypokalaemia, HYPERcalcaemia, hyperuricaemia). 4) Spironolactone/Amiloride: Cortical Collecting Duct (aldosterone antagonist / ENaC blocker → hyperkalaemia).
14	What clinical factors precipitate Lithium toxicity (>1.5 mmol/L), and how does coarse tremor differ from fine tremor?	Precipitated by dehydration, hyponatraemia/low-salt diet, and 'DAMN' drugs (thiazide diuretics, ACE inhibitors/ARBs, NSAIDs, metronidazole). Fine tremor is a benign side effect at therapeutic levels; coarse tremor, ataxia, dysarthria, nystagmus, and confusion indicate acute toxicity.
15	What is the MHRA warning regarding Fluoroquinolone antibiotics (Ciprofloxacin, Levofloxacin)?	Restrict use to severe infections where other antibiotics are inappropriate due to risks of disabling, potentially irreversible Tendonitis / Achilles Tendon Rupture (especially in patients >60, renal impairment, or co-prescribed corticosteroids), aortic aneurysm/dissection, peripheral neuropathy, and Clostridioides difficile infection.
16	What is the BNF rule regarding Clarithromycin (or Erythromycin) in a patient taking Simvastatin or Atorvastatin?	Withhold the statin while taking the course of Clarithromycin/Erythromycin because CYP3A4 inhibition markedly increases statin levels, risking severe myopathy and rhabdomyolysis.
17	In MRCP Part 1 Genetics, if both parents are asymptomatic carriers of an Autosomal Recessive condition (e.g., Cystic Fibrosis), what is the probability that an unaffected sibling of an affected child is a carrier?	2/3 (67%)—because the homozygous affected genotype (aa, 1/4) is already excluded once we know the sibling is phenotypically unaffected, leaving AA (1/3) and 2 Aa (2/3).
18	What is the BNF warning regarding co-prescribing Trimethoprim (or Co-trimoxazole) in a patient taking Methotrexate?	Strictly avoid—both are folate antagonists (dihydrofolate reductase inhibitors), and co-administration causes life-threatening pancytopenia/bone marrow aplasia.
19	What is the BNF rule for perioperative management of SGLT2 inhibitors (dapagliflozin, empagliflozin, canagliflozin) before major surgery or during acute illness?	Omit SGLT2 inhibitors the day before / during major surgery and during acute dehydrating illness because they can precipitate Euglycaemic Diabetic Ketoacidosis (ketones ≥3.0 mmol/L and acidosis despite normal/near-normal blood glucose <11 mmol/L).
20	In Clostridioides difficile (C. diff) infection, what is the NICE NG199 first-line and second-line antibiotic treatment?	First-line for a first episode (mild, moderate, or severe): Oral Vancomycin 125 mg QDS for 10 days. Second-line (or relapse within 12 weeks): Oral Fidaxomicin 200 mg BD for 10 days (Oral Metronidazole is NO LONGER first-line in NICE guidelines).
21	In MRCP Part 1 Cardiology, link the classic Jugular Venous Pulse (JVP) waveform abnormality to its pathology: 1) Cannon 'a' waves, 2) Giant 'v' waves, 3) Absent 'a' waves, 4) Kussmaul's sign (steep x & y descents).	1) Cannon 'a' waves: Complete (3rd-degree) heart block or VT (atria contracting against a closed tricuspid valve). 2) Giant 'v' waves: Tricuspid regurgitation. 3) Absent 'a' waves: Atrial fibrillation. 4) Steep x & y descents + Kussmaul's sign (JVP rises on inspiration): Constrictive pericarditis.
22	According to the BNF, what is the therapeutic serum concentration range for Lithium, when should blood samples be taken, and how often is maintenance monitoring required?	Target range: 0.4–1.0 mmol/L (0.8–1.0 mmol/L for acute manic relapse). Sample taken strictly 12 hours post-dose. Check levels weekly after initiation/dose change until stable, then every 3 months for the first year (6-monthly thereafter unless high risk), plus eGFR, TFTs, and calcium every 6 months.
23	Before starting Azathioprine or 6-Mercaptopurine for Inflammatory Bowel Disease, which enzyme activity must be checked to prevent fatal myelosuppression?	Thiopurine Methyltransferase (TPMT) activity; also avoid co-prescribing Allopurinol (xanthine oxidase inhibitor) as it blocks azathioprine breakdown and causes severe bone marrow suppression.
24	What is the classic acid-base disturbance in Salicylate (Aspirin) overdose, and when is urinary alkalinization or haemodialysis indicated?	Mixed respiratory alkalosis (direct stimulation of respiratory centre causing hyperventilation) and high anion gap metabolic acidosis (uncoupling of oxidative phosphorylation). Treat with IV Sodium Bicarbonate (urinary alkalinization enhances salicylate excretion) or Haemodialysis if serum salicylate >700 mg/L (or severe acidosis/renal failure/pulmonary oedema).
25	What is the most common adverse reaction to IV Acetylcysteine (NAC) in Paracetamol overdose, and how is it managed?	Anaphylactoid reaction (flushing, urticaria, wheeze, angioedema mediated by histamine release, NOT IgE): temporarily pause or slow the infusion, give chlorphenamine/nebulized salbutamol if needed, and restart NAC once settled.
26	Which classic drugs are potent Cytochrome P450 Inducers ('CRAP GPS') vs. Inhibitors ('SICKFACES.COM') that alter Warfarin INR?	Inducers (LOWER INR, reduce warfarin effect): Carbamazepine, Rifampicin, Alcohol (chronic), Phenytoin, Griseofulvin, Phenobarbital, St John's Wort. Inhibitors (RAISE INR, increase bleeding risk): Sodium valproate, Isoniazid, Cimetidine, Ketoconazole/Fluconazole, Erythromycin/Clarithromycin, Sulfonamides, Ciprofloxacin, Omeprazole, Metronidazole, Amiodarone, acute Alcohol, Cranberry/Grapefruit juice.
27	What is the specific antidote for severe Methotrexate toxicity or accidental daily overdose?	Folinic acid (Calcium leucovorin)—NOT folic acid—given IV immediately to bypass dihydrofolate reductase inhibition.
28	Which medications are well-known causes of Drug-Induced QT Interval Prolongation (risk of Torsades de Pointes—treat with IV Magnesium Sulfate 2 g)?	Macrolides (clarithromycin, erythromycin), Fluoroquinolones (ciprofloxacin, levofloxacin), SSRIs (especially Citalopram/Escitalopram), Tricyclic antidepressants, Antipsychotics (haloperidol, quetiapine), Ondansetron, Domperidone, Amiodarone, and Sotalol.
29	In Palliative Care opioid prescribing, how is the breakthrough PRN dose calculated from the total 24-hour background opioid dose?	One-sixth (1/6th) to one-tenth (1/10th) of the total 24-hour regular opioid dose, given every 2–4 hours as required, always co-prescribed with a regular laxative (senna/macrogol).
30	According to BNF guidelines, how must oral Methotrexate always be prescribed and monitored?	Prescribed strictly ONCE WEEKLY (never daily—specify the day of the week on the prescription) alongside Folic Acid 5 mg weekly on a different day. Monitor FBC, U&Es, and LFTs before starting, every 1–2 weeks until stable, then every 2–3 months.
31	In Gentamicin once-daily (Hartford) dosing, what are the two major organ toxicities, which neuromuscular disease is an absolute contraindication, and what is monitored?	Nephrotoxicity and irreversible Ototoxicity (vestibulocochlear nerve—screen for MT-RNR1 gene if possible). Contraindicated in Myasthenia Gravis. Monitor serum gentamicin levels (6–14h post-dose on Hartford nomogram or trough <1 mg/L) and daily renal function.
32	Which strong opioid transdermal patch or subcutaneous drug is safest in severe Renal Impairment / End-Stage Renal Failure (eGFR <15 mL/min)?	Fentanyl, Alfentanil, or Buprenorphine (metabolized by the liver with no active renally excreted metabolites; Morphine and Codeine accumulate neurotoxic morphine-6-glucuronide in renal failure).