DOTD pt5

Question 1

Drug Class: Ondansetron

Answer 1

Antiemetic

Question 2

Drug Class: Apixaban

Answer 2

DOAC
Direct oral anticoagulant

Question 3

Drug Class: Dalteparin

Answer 3

Low molecular weight heparin

Question 4

Drug Class: Warfarin

Answer 4

Vitamin K antagonist

Question 5

Indications: Ondansetron

Answer 5

post-op (anaesthetic waring off?) or post chemo nausea and vomitting

Question 6

Indications: Apixaban

Answer 6

VTE, AF

Question 7

Indications: Dalteparin

Answer 7

Thromboprophylaxis, VTE, acute coronary syndrome

Question 8

Indications: Warfarin

Answer 8

VTE, AF (if not suitable for DOAC), heart valve replacement

Question 9

Mechanism of action: Ondansetron

Answer 9

Serotonin antagonist, primarily centrally (inhibit CTZ), also in the gut where it reduces recretions and motility

Question 10

Mechanism of action: Apixaban

Answer 10

Inhibit both free Xa and that bound with antithrombin III

Question 11

Mechanism of action: Dalteparin

Answer 11

Enhance antithrombin III activity, inhibiting factor Xa

Question 12

Mechanism of action: Warfarin

Answer 12

Inhibits activation of vitK dependent clotting factors

Question 13

Adverse drug reactions: Ondansetron

Answer 13

Headache, GI upset, elevated liver enzymes, long QT syndrome

Question 14

Adverse drug reactions: Apixaban

Answer 14

Bleeding, skin reactions

Question 15

Adverse drug reactions: Dalteparin

Answer 15

Bruising, bleeding, heparin induced thrombocytopenia, hyperkalaemia (inhibits aldosterone release)

Question 16

Adverse drug reactions: Warfarin

Answer 16

Bleeding

Question 17

Contraindications, Warnings, DDIs: Ondansetron

Answer 17

Other drugs with risk of long QT
Amiodarone,
Antipsychotics (Chlorpromazine, Haloperidol, Quetiapine, Amisulpride, Thioridazine),
Antidep (Cetalopram, Fluoxatine, Sertraline, Amitriptyline)
ABx (Moxifloxacin, Clarithromycin, Ciprofloxacin, Levofloxacin, Trimethoprim-Sulfa, Azithromycin, Erythromycin)
Anti-cancer (Tamoxifen, Arsenic trioxide, Sunitinib)

Question 18

Contraindications, Warnings, DDIs: Apixaban

Answer 18

Macrolides increase [plasma]

Phenytoin and carbamazepine reduce [plasma]

Question 19

Contraindications, Warnings, DDIs: Dalteparin

Answer 19

Other antithrombotic agents, ACE inhibitors/ARBs, K sparing diuretics

Question 20

Contraindications, Warnings, DDIs: Warfarin

Answer 20

Loads:
- CYP2C9 inhibitors: amiodarone, clopidogrel, alcohol
- Reduces vit K: cephlosporin (kill gut bacteria that produce vit K)
- Displace warfarin from albumin: NSAIDs
- Accelerate warfarin metabolism: phenytoin, st johns wort
- Dietary vit K: avoid green leafy veg e.g. spinach, broccoli