Exam aid · Drugs and therapeutics

Drugs of Choice

The most-asked 'drug of choice' pairs in one place, grouped by system. Cover the right column and test yourself.

Tables to memorise

Cover the right-hand column and test yourself before checking.

Condition	Drug of choice
Anaphylaxis	IM adrenaline 0.5 mg (1 in 1000)
Status epilepticus	IV lorazepam (or buccal midazolam outside hospital)
PSVT	Adenosine
Torsades de pointes	IV magnesium sulphate
Eclampsia	Magnesium sulphate
Hyperkalaemia with ECG changes	IV calcium gluconate, then insulin + glucose
Malignant hyperthermia	Dantrolene
Acute angina attack	Sublingual glyceryl trinitrate
Severe hypoglycaemia (unconscious)	IV glucose or IM glucagon
Cardiac arrest	Adrenaline 1 mg IV (1 in 10,000)

Infection	Drug of choice
Syphilis	Benzathine penicillin G
MRSA (serious)	Vancomycin
C. difficile colitis	Oral vancomycin or fidaxomicin
XDR typhoid (oral)	Azithromycin; meropenem if severe
P. vivax malaria	Chloroquine + primaquine
P. falciparum malaria	Artemisinin combination therapy
Severe malaria	IV artesunate
Pneumocystis pneumonia	High-dose co-trimoxazole
Amoebiasis / giardiasis	Metronidazole
Herpes simplex / zoster	Acyclovir or valacyclovir
CMV retinitis	Ganciclovir
Influenza	Oseltamivir
Scabies	Permethrin 5%
Cryptococcal meningitis	Amphotericin B + flucytosine

Condition	Drug of choice
Absence seizures	Ethosuximide (valproate if mixed)
Trigeminal neuralgia	Carbamazepine
Bipolar disorder (maintenance)	Lithium
Myasthenia gravis	Pyridostigmine
Parkinson's disease	Levodopa + carbidopa
Neuroleptic malignant syndrome	Dantrolene ± bromocriptine
Type 2 diabetes (first line)	Metformin
Diabetic ketoacidosis	IV soluble insulin + fluids + potassium
Hypothyroidism	Levothyroxine
Hyperthyroidism in 1st trimester	Propylthiouracil
Central diabetes insipidus	Desmopressin
Nephrogenic diabetes insipidus	Thiazide diuretic
Addisonian crisis	IV hydrocortisone
Hypertension in pregnancy	Labetalol, nifedipine or methyldopa

Adrenaline for anaphylaxis is given IM into the outer thigh, not IV, outside resuscitation settings.
Benzathine penicillin is also used for secondary prophylaxis of rheumatic fever.
Physostigmine, not neostigmine, reverses central anticholinergic toxicity.
Primaquine needs a G6PD test first.
Thiazides paradoxically reduce urine volume in nephrogenic diabetes insipidus.
Propylthiouracil is preferred in the 1st trimester; switch to carbimazole later.

ABC of anaphylaxis: Adrenaline Before Chlorphenamine: Adrenaline is life-saving; antihistamines and steroids are only adjuncts.
Magnesium for the 'Ms' and 'Ts': Magnesium sulphate treats eclampsia (Mothers) and torsades (Twisting QT).

Attempt MCQs on these topics while the sheet is fresh. Anything you get wrong goes to your incorrect list for the next round.