Drugs in medicine

Question 1

Which drugs can reduce the anticoagulant effects of Warfarin?

Answer 1

Cytochrome p450 inducers e.g.

• Carbamazepine
• Rifampicin
• Amiodarone
• Phenytoin
• Citalopram
• Alcohol (chronic)

Question 2

Which drugs can increase the anticoagulant effects of Warfarin?

Answer 2

Cytochrome p450 inhibitors e.g.

• Metronidazole
• Amiodarone
• Ciprofloxacin
• Erythro/clarithromycin
• Fluconazole
• Isonazid
• Alcohol (acute)
• Grapefruit juice

Question 3

What are some examples of drugs reliant on hepatic metabolism?

Answer 3

Morphine sulphate

Methotrexate

Question 4

What are two examples of Cytochrome p450 drugs that have a NTI?

Answer 4

Warfarin

Aminophylline

Question 5

What drug class is Warfarin? MoA?

Answer 5

Vitamin K antagonist.

Prevents gamma-carboxylation of clotting factors 2, 7, 9 and 10 and prolongs the extrinsic pathway

Question 6

What is the target INR when on warfarin?

Answer 6

2. 5 for DVT/PE

3. 5 for recurrent VTE or metal heart valves

Question 7

How is Warfarin usually loaded?

Answer 7

With LMW heparin cover as can take >3d to reach therapeutic levels

Question 8

How is the effect of warfarin reversed?

Answer 8

• If life threatening bleed - give activated prothrombin complex (Octaplex), vitamin K

Question 9

When should warfarin be avoided?

Answer 9

In pregnancy - it is teratogenic - use LMWH instead

Question 10

Side effects of Warfarin

Answer 10

• Haemorrhage risk
• Minor bleeding
• Skin necrosis
• Alopecia

Question 11

How does heparin work?

Answer 11

It is a mucopolysaccharide that potentiates anti-thrombin.

Irreversibly inactivates factors 2a (thrombin) and 10a

Question 12

How are Unfractionated and LMW heparin administered?

Answer 12

Unfrac. - IV infusion

LMW - Sub cut injections

Question 13

Three other examples of parental anticoagulants

Answer 13

Hirudin (used in place of heparin in patients with HIT)
Heparinoids e.g. Danaparoid
Fondaparinux - potentiates anti-thrombin, inhibits factor Xa

Question 14

Which heparin is safe in renal failure?

Answer 14

Unfractionated heparin

LMWH - must have a creatinine clearance >30ml/min)

Question 15

Two examples of DOACs

Answer 15

Rivaroxaban

Dabigatran

Question 16

What is Rivaroxaban?

Answer 16

a DOAC

Direct factor Xa inhibitor - causes irreversible anticoagulation

Question 17

Dosing of rivaroxaban

Answer 17

15mg BD for 3w then 20mg OD

Question 18

What drug class is Dabigatran?

Answer 18

Direct thrombin inhibitor

Question 19

Dosing of dabigatran

Answer 19

150mg BD (treatment dose)
110mg BD (prophylaxis dose)

Question 20

What is the reversal agent for dabigatran?

Answer 20

Praxbind (Idarucizumab)

Question 21

At what CHADSVASC score should a DOAC or warfarin be given

Answer 21

> or =2

Question 22

When is rhythm control for AF preferred?

Answer 22

• Symptom improvement
• Younger patient
• Heart failure related to AF
• Adequacy of rate control

Question 23

When is Ezetimibe monotherapy recommended?

Answer 23

treating primary hypercholesterolaemia in adults in whom statin therapy is contraindicated or not tolerated

Question 24

What are some examples of PCSK9 inhibitors?

Answer 24

Alirocumab, Evolocumab

Question 25

How do PCSK9 inhibitors work?

Answer 25

Prevent PCSK9 from binding to LDLRs (PCSK9 promotes LDLR degradation in the liver, meaning the LDL-C blood levels increase)

Question 26

What can be used as an addition to or replacement of a beta blocker in HF if the heart rate is still too high? (>75)

Answer 26

Ivabradine

Question 27

What can be used instead of ACEi/ARBs (e.g. if they are contraindicated, or in Black people)

Answer 27

Hydralazine + nitrate

Question 28

Beta blocker administration in acute HF treatment

Answer 28

Beta blockers should be continued but don't initiate them

Question 29

When are ACEi/ARBs contraindicated?

Answer 29

In pregnancy/breastfeeding - use an alternative e.g. labetalol

Question 30

Target blood pressure in hypertension

Answer 30

140/90 or less in under 80s | 150/90 or less in over 80s

Question 31

What is a hypertensive emergency?

Answer 31

Severe HTN > 180/120 with acute damage to target organs (lower BP within minutes to hours)

Question 32

What is hypertensive urgency?

Answer 32

Severe HTN without acute damage to target organs | - Lower BP after a review within 7 days

Question 33

Examples of acute target organ damage in severe HTN

Answer 33

``` Eyes - papilloedema Brain - encephalopathy, stroke Heart - pulmonary oedema, MI Kidneys - AKI Aortic dissection ```

Question 34

Treatment of hypertensive emergency

Answer 34

IV therapy - labetalol, GTN, sodium nitroprusside, esmolol Target BP of 160/100 within 6h

Question 35

Blood tests to do before statin initiation

Answer 35

``` Lipid measurement LFTs Renal function HbA1c TSH CK ```

Question 36

How is hypertriglyceridaemia treated?

Answer 36

Exclude excess alcohol and poor glycaemic control If over >20 refer to specialist. If 10-20, do a fasting sample (if that is over >10 then refer) Fenofibrates and omega-3 acid under specialist supervision

Question 37

What are some examples of antiplatelet drugs? and MoA? (5)

Answer 37

Aspirin (COX inhibitor) Clopidogrel (ADP receptor blocker) Dipyramidole (Inhibits phosphodiesterase) Prostacyclin (stimulates adenylate cyclase) Glycoprotein IIa/IIb inhibitors e.g. adciximab