Drugs

Question 1

Apixiban

Answer 1

Anti-coagulant
Directly inhibits factor Xa reversibly so prolongs PT, INR, and aPTT
Reduces risk of stroke and embolism in AF and post-orthopaedic surgery
2.5mg BD for VTE prophylaxis, 10mg BD to treat DVT/PE
Side-effects: anaemia, haemorrhage

Question 2

Losartan

Answer 2

Angiotensin-receptor blocker (ARB)
Competes with angiotensin II for binding to receptor so antagonises the RAAS system & lowers BP. Unlike ACE, ARBs don’t cause dry cough.
- Treats HTN, diabetic nephropathy, ventricular hypertrophy

Question 3

Amlodipine

Answer 3

Calcium-channel blocker (CCB)
Affects myocardial cells, conducting myocytes and vascular smooth muscle by inhibiting voltage-gated L-type calcium channels --> prevents calcium influx and results in reduced myocardial contractility, electrical impulses of the heart and coronary/systemic vascular tone. 
- essential HTN
- stable angina 
5mg OD PO

Question 4

Atorvastatin

Answer 4

Statins competitively inhibit HMG-CoA reductase in the liver, an enzyme in cholesterol synthesis. Decreased hepatic cholesterol levels increases hepatic uptake of cholesterol to reduce plasma cholesterol.
Decreases LDL, apoB, triglycerides and increases HDL

• familial/primary hypercholesterolaemia 10mg OD
• prevention of CVS events for high risk patients 20mg OD
• secondary prevention of CVS events 80mg OD

Question 5

Alendronic acid

Answer 5

Bisphosphonate.
Bisphosphonates are absorbed onto hydroxyapatite crystals in bone to slow their rate of growth and dissolution to slow down bone turnover. Interferes with osteoclast function (reduces bone absorption)

• postmenopausal osteoporosis 10mg OD
• osteoporosis in men 10mg OD
• prevention of corticosteroid-induced osteoporosis in postmenopausal Fs 10mg OD

Side effects: alopecia, anaemia, constipation

Question 6

Dalteparin

Answer 6

LMWH anti-coagulant
More predictable response, greater bioavailability, longer half-life than unfractionated heparin. Potentiates antithrombin III to inhibit formation of factor Xa and thrombin (affects Xa more than thrombin)

• prophylaxis of DVT in surgical patient 5000 units
• treatment of DVT or PE 10000+ units
• patients with unstable CAD (e.g. unstable angina, NSTEMI)

Side effects: haemorrhage, thrombocytopenia