PSA- Classic Drug Monitoring

Question 1

Vancomycin Class = Gycopeptide

Must check what before?

Where is it toxic to? (2)

What can be caused a week later?

Very very rare side effect

Answer 1

Creatinine - because it is renally excreted

• Nephrotoxic
• Ototoxic

Neutropeania

Thrombocytopaenia (low platelets)

Question 2

Everone should have what checked before starting statin?

Only some should have what checked befreo starting statin?

Why and risk factors for this? (6)

Answer 2

LFTs

Creatinine kinase

Rare side effect - myopathy
Risk factors:
1. Family hx
2. Past med hx - or prev. muscle toxicity
3. high alcohol intake
4. renal impairment
5. hypothyroidism
6. elderly

Question 3

Phenytoin

Loading dose for status epileptics?

Maintenance dose?

Answer 3

20mg/kg

Maintenance dose?
adults - 200 - 500mg daily

Question 4

Lithium
When should serum. conc. be measured?

normal therapeutic window?

when should lithium serum monitoring occur and for how long?
Changing dose -
When stable -

What elcetrolyte can change the serum conc. of lithium?

Answer 4

12 hours after last dose

0.4-0.8mmol/L (toxicity could occur >1.0)

• Weekly after every dose change
• Every 3 months when the conc. is stable

Sodium
- therefore diet and dehydration can cause toxicity!

Question 5

Methotrexate
when is it given?
what else is prescribed with it and when is that given?

Side effects? (5)

What to NEVER prescribe with it? (2)

Another interaction?

Answer 5

when is it given?
weekly via injection or tablet

what else is prescribed with it and when is that given?
Folic acid 24 hours after methotrexate dose

Side effects? (5)
1. Teratogenic
2. liver toxicity
3. lung toxicity (fibrosis)
4. bone marrow surpression (leukopaenia)
5. mouth ulcers

What to NEVER prescribe with it? (2)
1. trimethoprim
2. co-trimoxazole

HIgh dose aspirin can increase methotrexate toxicity risk by dec. excretion

Question 6

Methotrexate monitoring
whats needed when started and then when stable?

Is a CXR needed prior?

If abnormal LFTs can you start it?

If WBC or platelets drop when on it, do what?

Answer 6

U+E, FBC, LFT
Weekly when starting and dose change
every 2-3 months when stable

Not NEEDED but rheum advise

If abnormal LFTs can you start it?
NO

If WBC or platelets drop when on it, do what?
Stop it immediately

Question 7

Olanzipine (atypical antipsych)

the main side effect?

when is ECG needed?

Answer 7

Weight gain, diabetes and hyperglycaemia - therefore check BM/ Hba1c

only in PM hx of CV disease or risk factors

Question 8

GP starts girl on COCP - what test is needed and why?

Answer 8

BP
- HTN uncontrolled is a contraindication

Question 9

Amioderone ( class III anti-arrhythmic drug which blocks K+ channels preventing repolarisation)

whats needed PRIOR to starting? (3)

one is then needed every ….

Answer 9

K+ levels - hypOkalaemia can cause arrythmias on it
CXR
LFTs

LFTs needed every 6 months

Question 10

Carbimazole (block and replace)

Whats checked when someone has a sore throat?

can also affect …

Answer 10

Neutrophil count (FBC) - bome marrwo surepssion and agranulocytosis

LFTs but check this later not priority

Question 11

Gentamicine (aminoglycoside)

In ENDOCARDITIS:
1 hour (peak) concentration range =
Predose (trough) concentration range -=

In Everything else:
1 hour (peak) concentration range =
Predose (trough) concentration range -=

is renal check needed?

Answer 11

Endocarditis:
1 hour (peak) concentration range =
3-5mg/L

Predose (trough) concentration range =
<1mg/L

Everything else:
1 hour (peak) concentration range =
5-10mg/L

Predose (trough) concentration range =
<2mg/L

NO!

Question 12

Ramapril
what needs to be checked at basline and dose change?

why? (2)

Answer 12

U+E

can cause
Hypokalaemia
hyponatraemia

Question 13

Digoxin

Where is it excreted and therefore what needs to be measured?

when testing therapeutic dose when should you check concentration?

what electroltyel change can cuase increase in toxocity?

Answer 13

Kidneys

Check U+Es

6 hours after dose

HypOkalaemia

Question 14

Sodium valproate

monitor what prior? and then how often?

Measure what before hand too? and before surg?

Answer 14

LFTs (casues liver tox)
Test for 6 months

FBC

Question 15

clozapine

main side effect =

monitor …. for
first -
then -
then -

interaction with… can cause increased clozapine metabolism

Main side effects:
C
Lo
Z
A
P
I
N
E

Answer 15

main side effect = agranulocytosis

monitor FBC for
first - 18 weeks
then - fornite 32 weeks
then - monthly

Nicotine! ask about smoking

C - constipation
Lo - Lowers seizure threshold!
Z - Zzz sedation
A - agranulocytosis
P- phat weight gain
I - increased saliver
N- neutropaenia
E - ecg changes