advice

Question 1

Allopurinol
1. MOA
2. Indication
3. Normal dose
4. Counsel
5. Warning signs (and action)
6. Renal/hepatic/P/BF/Child

Answer 1

1. Reduce uric acid in body. xanthine oxidase inhibitor
2. Gout PREVENTION (not tx - don’t start during acute attack), Kidney stones, hyperuricaemia due to chemotherapy (start before chemo)
3. Normal dose: 100mg OD
4. Counsel: after food, plenty of water
5. warning signs: rash (stop - may be SJS)
6. Metabolised in the liver and excreted by kidney. monitor renal/hepatic.
   P-Y/BF-y
   Interaction: Mercaptopurine, azathioprine (require xanthine oxidase) increased [m, a]
   increased sensitivity with amoxicillin, ACEi, thiazide

Drug induced gout: thiazide or loop diuretics, Low-dose aspirin

Question 2

Amitriptyline
1. TCA
2. Indication
3. Normal dose
4. Counsel
5. Warning signs (and action)
6. Renal/hepatic/P/BF/Child

Answer 2

1. MOA
2. Indication: pain (25-75mg), migraine prophylaxis (“), depression (50-150mg/2 doses)
3. Lower dose in elderly. Titrate slowly (to reduce SE)
   CI: arrhythmia, heart block, immediate after MI, manic phase
4. Counsel: keep taking. drowsy, dry mouth, constipation.
5. Warning signs: fatal in overdose (Limit quantity), QT prolongations, anticholinergic syndrome. withdrawal effect (reduce over 4w)
6. Avoid in severe hepatic. P-Y/BF-Y

Question 3

THIAZIDE E.g bendroflumethiazide, indapamide

Answer 3

1. Thiazide diuretics, inhibit the Na+/Cl− co-transporter in distal convoluted tubule of nephron.
2. HTN 2.5mg OM, oedema 5-10mg OM
3. lower dose for elderly,
4. Counsel: OM. no NSAIDS. Possible impotence
   Can exacerbate DM (hyperGlycaemia), gout (reduce UA excretion), SLE.
5. Warning signs: hyPOkalaemia, hyPOna -> arrythmia.
6. Avoid in severe renal (<30ml/min) & NSAIDs reduce effectiveness
   Interaction: loop (lower K), NSAID
   Synergistic with ACE inhibitors and ARBs SE hyperkalaemia

Question 4

Co-careldopa (carbidopa and levodopa) Cmg/Lmg

Answer 4

1. Carbidopa, prevent LD from being broken down before reaches brain. LD convert into dopamine in brain.
2. Parkinsons (rigidity and slow movement)
3. BD, TDS, ensure ON time doses. MR may mitigate on-off effect. Avoid with large meal
   when transferring, stop previous form for 12hr
4. Counsel: sudden onset of sleep. darker urine.
5. Risk of impulse disorder, developing dopamine dysregulation syndrome; addiction-like symptoms - Report. Avoid abrupt withdrawal
   MHRA: LD can cause impulse control disorder
6. Caution in Renal/hepatic/P. BF - avoid, suppress lactation
   interaction: iron (1 hr window - reduce absorption)
   Antipsychotics, metoclopramide as effects on dopamine receptors are contradictory.

Question 5

Ferrous sulphate

Answer 5

1. Body needs iron to make RBC
2. iron deficiency anaemia prophylactic 200mg OD and Tx 200mg TDS
3. lower dose in elderly
   Continue for 3m to replenish stores.
4. Counsel: best absorbed on empty stomach. reduce SE with food. Darker stool.
   SE: C/D/N, GI discomfort
5. Warning signs: faecal impaction.
   Antidote: Desferrioxamine

Question 6

Ispaghula husk

Answer 6

Ispaghula husk
1. Bulk forming, contains fibre, increasing faecal mass which stimulates peristalsis.
4. Counsel: avoid at night, Stir in >150ml of water & drink asap.
Adequate fluid to avoid oesophageal or intestinal obstruction.
5. CI: faecal impaction; intestinal obstruction; reduced gut motility

Question 7

Lactulose

Answer 7

1. Osmotic, stool softener
2. Constipation, hepatic encephalopathy (reduces ammonia absorption)
3. If necessary, it may be mixed with water, fruit juice or squash.
   CI: GI obstruction/perforation, galactosaemia
   SE: bloating, wind
   Can increase Warfarin effect

Question 8

Genitourinary anti-muscarinic - Oxybutynin, solifenacin

Answer 8

2. Overactive bladder
3. review every 6w until stable symptoms, then 6mly
4. w//out food. ensure drinking enough water.
   SE: Drowsy, dry mouth, constipation, facial flushing.
   CI in AM (glaucoma, myasthenia gravis), acute porphyria
5. CAUTION in Renal/hepatic. P-N/BF-N/Child (>5)
   Interaction: TCA (increase AM SE)

Solifenacin
max 5mg OD if <30mL/min, moderate hepatic, with potent 3A4 inhibitor. avoid in severe hepatic.
QT? prolongation
Counsel: with water (other drinks may release solifenacin in mouth)

Question 9

Quinine for cramps

Answer 9

2. Cramps prophylaxis 200-300mg ON (4w trial),
   Malaria (Plasmodium falciparum) Xmg/kg (dose not valid for quinine bisulfate) reduce parental dose in severe H/R
3. IV dose based on weight and given as slow infusion
4. Counsel: takes weeks to work.
5. Warning signs: unusual itching, rash, deafness or blindness, palpitations. Teratogenic.
   OVERDOSE: arrythmia, convulsions
   MHRA: Dose-dependent QT-interval-prolonging effects. Monitor ECG during parental tx
   CI: Haemoglobinuria; myasthenia gravis; optic neuritis; tinnitus, G6PD deficiency
6. Renal reduce/hepatic/P-malaria RvB/BF-Y
   interaction: QT (amiodarone, antipsychotics, quinolones, macrolides, SSRIs.)

Exclude: electrolyte disturbances, drug causes (e.g. statins, β2-agonists), and attempt stretching

Question 10

Tamoxifen

Answer 10

1. Anti-oestrogen
2. Infertility, breast cancer prophylaxis.
3. 20mg OD (once weekly for gynaecomastia - UL)
4. Counsel: contraception, endometrial cancer (vaginal bleed, pelvic pain), thromboembolism (breathless, pain in one leg)
5. CI if hx of VTE
   SE: hot flushes, nausea, vision problems, genital itching
   WARNING SIGN: endometrial changes, risk of VTE
   P-N/BF-N supress lactation