Therapeutics

Question 0

What would you prescribe in acute alcohol withdrawal and why?

Answer 0

Chlordiazepoxide (BZD)- reducing dose vs. features of autonomic overactivity (agitation, sweating, tremors, NnV) and DT, fits etc.

Pabrinex (Thiamine ) - 4 ampoules IV TDS, 3 days to prevent Korsakoffs (irreversible) and reverse Wernickes (nb thiamine used up in metabolism of alcohol)

Question 1

What are the thromboprophylactic doses of enoxaparin?

Answer 1

40mg = normal

20mg if creatinine clearance <30ml/min

Question 2

What are the most common P450 inducers?

Answer 2

P = phenytoin
C = carbamazepine

B = barbituates
R = rifampicine
A = alcohol (chronic)
S = sulfonylureas
S = St Johns Wart
S = smoking

Question 3

What dose of enoxaparin for:
1) Treatment DVT/PE
2) Treatment Unstable angina/non-Q wave MI
For normal pts and pts with creatinine clearance <30ml/min?

Answer 3

1) 1.5mg/kg OD OR 1 mg/kg OD

2) 1 mg/kg BD OR 1 mg/kg OD

Question 4

Following DVT what drugs would you start and when?

Answer 4

Enoxaparin (acute) and warfarin (long-term cover), both starting ASAP

Question 5

What is the antidote to warfarin?

Answer 5

1mg vitamin K

Question 6

What is the antidote to heparin?

Answer 6

Protamine sulphate

Question 7

Is aspirin suitable thromboprophylaxis against DVT?

Answer 7

No, aspirin is an antiplatelet and is therefore more involved in preventing arterial based iscaemia (eg angina) and not disease where stasis is the cause (DVT)

Question 8

What is Wirchoffs triad and what does it consist of?

Answer 8

Details factors leading to clot formation

1) hypercoagulability
2) Vessel wall damage (–> turbulent blood flow)
3) Stasis of blood

Question 9

How long does warfarin take to reach therapeutic levels?

Answer 9

72 hours

Question 10

How would you monitor unfractionated heparin?

Answer 10

APTT

Question 11

How does warfarin work?

Answer 11

Irreversible vitamin K antagonist –> reduced Factor II, VII, IX, X and protein C + S (physiological clotting factors)

Question 12

When would you use unfractionated heparin and why?

Answer 12

Patients with venothrombosis but at increased risk of bleeding (eg. DVT in pt coming back from surgery) as much shorter t1/2 vs enoxaparin (LMWH)

Question 13

What are the side effects of heparin?

Answer 13

^rx bleeding
Heparin induced thrombocytopenia (HIT)
Hypersensitivity
Osteoporosis + ^Ca2+ (altered aldosterone fXn)

Question 14

What is the best route of PRN administration in a dying patient?

Answer 14

S/C

Question 15

When would you consider a syringe driver in a dying patient?

Answer 15

> 2 doses S/C prn
Reduced oral intake
Multiple symptoms
Vomiting
GI obstruction

Question 16

How much morphine PO/day is equivalent to codeine 60mgs QDS?

Answer 16

(60mgx4)/10 = 24mg

Question 17

How much morphine PO/day = Tramadol 100mg QDS?

Answer 17

(100mg x 4)/10 = 40mg

Question 18

What is the conversion rate for oral morphine –> syringe driver? And is it different for diamorphine?

Answer 18

Morphine = 1/2 dose
Diamorphine = 1/3 dose

Question 19

How much PRN S/C morphine should you prescribe to a patient who has already been on morphine?

Answer 19

Current dose/6 (t1/2 approximately 4 hours)

Question 20

What is the doctrine of double effect?

Answer 20

Explains the permissibility of an action that may cause serious harm/deterioration to a patient if the outcome is for their overall benefit. Particularly used in palliative care to justify making patient comfortable.

Question 21

If a patient is being transferred to oxycodone S/C or syringe driver from another route, how should you calculate the new dose?

Answer 21

S/C = divide by 6

Syringe driver = divide by 2

Question 22

What are the symptoms dying patients frequently have?

Answer 22

Pain
Breathlessness
Nausea and vomiting
Respiratory secretions
Anxiety

Question 23

How would you manage shortness of breath in a dying patinet?

Answer 23

O2 therapy (only if hypoxic, trial nasal prongs 1 hour to see if helps)
Fan therapy
Opiates (start 2.5mg PRN)
BZDs (vs anxious pts only?)

Question 24

Where is the chemoreceptor zone?

Answer 24

Floor of the 4th ventricle

Question 25

How would you manage terminal respiratory tract secretions?

Answer 25

Suctioning - only if pt = unconscious
Buscopam (hyoscine butylbromide) - 20mg S/C. Anti-muscarininc agent. Can give hourly BUT if 120-160mg and no effect then unlikely to help.

Question 26

What two causes of terminal agitation should be ruled out before commencing drugs?

Answer 26

Urinary retention

Constipationm

Question 27

What drugs would you use to treat terminal agitation?

Answer 27

Midazolam - 2.5 - 5mg S/C PRN
Haloperidol 1.5mg S/C PRN
Levomepromazine 6.25mg S/C PRN

Question 28

What would you use to treat NnV in a terminal patient?

Answer 28

Levomepromazine - 6.25mg

Haloperidol - 1.5mg –> max 10mg/24 hours