Pharm/tox

Question 1

Which of the following is not associated with photosensitivity?

1) CBZ
2) Amiodarone
3) Lithium
4) TMP-SMX
5) Captopril

Answer 1

3. Lithium

Photosensitivity drugs (top 10)

Doxycycline
Hydrochlorothiazide
Amiodarone
Piroxicam
Chlorpromazine
Co-trimoxazole
Captopril
Enalapril
Bendroflumethiazide
Carbamazepine

Question 2

SICK FACES?

CRAP GPs?

Answer 2

SICK FACES = CYP3A4 inhibitors

SSRIs
Isoniazid
CCBs (verapamil,diltiazem)
Ketoconazole
Fluconazole, metronidazole
Amiodarone, allopurinol, ACUTE alcohol, antiretrovirals
Clarithromycin
Erythromycin
Sodium valproate, sulfonamide

+ grapefruit juice

CRAP GPs = CYP3A4 inducers

Chronic ETOH
Rifampicin
Anti-epileptics (CBZ)
Phenytoin

Griseolfulvin
Phenobarituate
Smoking/St Johns wort

Question 3

What is the equivalent of the following to 10mg PO morphine:

• endone
• S/C morphine
• hydromorphone PO and s/c

Answer 3

10mg morphine PO =

3mg morphine subcut (3)

7mg endone PO (1.5)

2mg hydromorphone PO (5)

Question 4

Hydromorphone 10mg subcut to PO?

Morphine equivalent?

Answer 4

10mg subcut = 30mg oral (3)

30mg hydromorph PO = 150 PO morphine (5)

Question 5

Equation for drug clearance

Answer 5

clearance = (Vd x 0.7)/half life

Question 6

amiodarone increases cyclosporine concentrations via which mechanism?

Answer 6

PGP inhibition

Question 7

Name 3 drugs which follow zero order kinetics

Answer 7

Alcohol
Phenytoin
Aspirin/salicylates

Question 8

What is the active isomer of Warfarin?

Answer 8

S-warfarin (super warfarin!)

Question 9

A patient is given 320mg loading dose of a medication. The peak serum concentration is 20mg. What is the Vd?

Answer 9

Vd = loading/peak concentration

320/20 = 16L

Question 10

Equation for loading dose

Answer 10

Loading dose = Vd x target plasma concentration.

Question 11

Difference between a non-competitive and competitive antagonist

Answer 11

Competitive antagonist
- Reversible binding. Maximum effect CAN be reached with higher dose of agonist (curve shifts right)

Non-competitive antagonist
- Non-reversible binding. Maximum effect CAN-NOT be achieved with higher dose of agonist (curve shifts down)

Question 12

What is tachyphylaxis

Answer 12

Phenomenon of rapid decrease in the response to a drug due to previous (long term) exposure to that drug (i.e. amphetamines)

Question 13

Indications for a liver transplant in panadol overdose

Answer 13

Acidosis (ph 7.3)
Raised lactate (>3.0 with acidosis, >3.5 without)
Coagulopathy (raised INR) + encephalopathy + AKI (creat >300)

Question 14

Which class(es) of diabetic medications are associated with pancreatitis?

Answer 14

GLP1 agonists

DPP4 inhibitors

Question 15

Which enzyme is involved in the metabolism of clopidogrel?

What is it’s effect on clopidogrel efficacy?

Answer 15

CYP2C19

Metabolizes clopidogrel to it’s active compound - therefore inhibiting CYP2C19 actually DECREASES clopidogrel’s efficacy

Question 16

Against which receptors does norepinephrine have an agonist effect?

Answer 16

alpha1 and alpha 2

beta 1

Question 17

Which medication classes are associated with jaw osteonecrosis

Answer 17

Antiresorptives* - RANK ligand inhibitors (denosumab), bisphosphonates

VEGF inhibitors - Mabs (i.e. bevacizumab, , TKIs (i.e. Sunitinib, lenvatinib)

*more common in cancer patients (high doses, immunosupressed)

Question 18

Treatment for aspirin overdose

Answer 18

Urinary alkalization OR hemodialysis if indicated (i.e. severe AKI/CKD and can’t clear)

Charcoal if present within 2 hours

Question 19

Drugs associated with crystal nephropathy

Answer 19

Acyclovir
Sulfonamide antibiotics (i.e. TMP, bactrim)
Ethylene glycol
Mega dose vitamin C
MTX
Protease inhibitors
“-navirs”

Question 20

Which of the following has the greatest influence on steady state drug level? 
A. Clearance 
B. Elimination 
C. Half-life 
D. Volume of distribution 
E. Protein bounding

Answer 20

clearance

Question 21

A drug has a fraction excreted unchanged of 0.1 and a total body clearance of 50L/hr. Liver blood flow is 90/L.

What is the maximum bioavailability of the drug?

A. 40%
B. 70%
C. 90%
D. 50%

Answer 21

D - 50%

Biovailability = 1 - HER

HER = total hepatic clearance/total liver blood flow.

Renal clearance 10%, therefore hepatic clearance 90%

90 + 10 = 50L (total body clearance)

Therefore 90% x 50L –> 45L/hr (hepatic clearance)

Liver blood flow = 90

45/90 = 50% therefore HER = 50%

100 - 50% = 50%

Question 22

Which P2Y12 receptor antagonist irreversbly binds the receptor?

Answer 22

Ticagrelor (therefore short half life and TWICE daily dosing)

Prasugrel and clopidogrel = irreversible
binding

Question 23

Name the receptor for each anti-emetic:

• palonosetron
• cyclizine
• aprepitant
• olanzapine
• metoclopramide

Answer 23

Palonosetron = 5HT3
Cyclizine = 5HT1 
Aprepitant = NK1 receptor
Olanzapine = 5HT2 + dopamine
Metoclopramide = D2 + 5HT3

Question 24

Statins that undergo CYP3A4 metabolism

Answer 24

atorvastatin

simvastatin

Question 25

Metabolism of isoniazid

Clinical relevance?

Answer 25

Primarily metabolized by acetylation and dehydrazination

Rate of acetylation is genetically determined.
- 50% are “slow acetylators” and 50% “rapid acetylators” (more common in asians)

slow acetylation = higher blood levels, more toxicity (i..e HEPATITIS)
rapid acetylation = lower blood levels, less efficacy