Drug Monitoring Flashcards

1
Q

which drugs with a narrow therapeutic index usually require monitoring?

A
  • digoxin
  • theophylline
  • lithium
  • phenytoin
  • Abx (gentamicin and vancomycin)
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2
Q

features of digoxin toxicity?

monitor?

A

confusion
N
visual halos
arrhythmias

creatinine (renal dysfunct)

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3
Q

features of Li+ toxicity?

safe serum level?

how to monitor?

A
  • early:
    TREMOR, diarrhoea
  • intermediate: TIRED
  • late: ARRHYTHMIA, seizures, coma, renal failure and diabetes insipidus

0.4-0.8

take 12 hours post dose
serum level weekly - if stable - 3 months
advise patient not to drop sodium intake

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4
Q

features of phenytoin toxicity?

how to monitor?

A
  • gum hypertrophy
  • ataxia
  • nystagmus
  • peripheral neuropathy and teratogenicity

serum levels, if IV use, monitor ECG and BP
(trough levels immediately before dose should be checked if:
-adjustment of phenytoin dose
-suspected toxicity
-detection of non-adherence to the prescribed medication)

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5
Q

features of gentamicin toxicity?

A

ototoxic

nephrotoxic

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6
Q

features of vancomycin toxicity?

what to monitor?

A

ototoxic
nephrotoxic
renal function - serial creatinine

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7
Q

what do if evidence of drug toxicity? (3)

A

1) stop drug +/- alternative
2) supportive measures (IV fluids)
3) antidote

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8
Q

how is gentamicin given and monitored?

A

its given IV once daily (unless renal problems then 12 hourly)

gentamicin levels are measured between 6-14 hours after dose given “high trough”, and a normogram is used to plot hr-after against the conc

this plot will show whether to give next dose at 24/36/48 hours

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9
Q

normal range for gentamicin?

if Tx endocarditis?

A

5-10mg/L

3-5mg/L

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10
Q

Tx paracetamol OD?

A
  • NAC (N-acetyl cysteine)
  • IV fluids

nomogram is used: > 4hr after ingestion, if the plasma paracetamol level is below the line, the patient does NOT require NAC; if the plasma level is above the line,
they DO

(if staggered OD, or time is unknown, Tx with NAC)

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11
Q

paracetamol toxic metabolite?

A

NAPQI

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12
Q

what is measured in aminophylline THERAPEUTIC monitoring?

A

O2 sats

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13
Q

what is measured in aminophylline TOXIC monitoring?

A

serum aminophylline

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14
Q

how to monitor S/E of statins?

A
  • full lipid profile (non-fasting), TSH, U&E, LFTS ( ALT must be <3x upper limit)

+/- high risk: Hx/FHx muscular disorders/toxicity, ↑alcohol, renal ↓, ↓thyroid, elderly) then DO baseline CK!

check at 3m and 12mths, if marked ↑ in Sx or CK: STOP

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15
Q

how to monitor ACEi when starting?

A

do renal function 1-2 weeks after

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16
Q

how to monitor methotrexate when starting?

what if wbc ↓?

what if abnormal LFTs?

A

do liver/renal 1-2 weeks at first, then 3 monthly
avoid in liver/renal dysfunct

STOP!

due to liver cirrhosis risk, Tx with methotrexate should not be started if LFTs abnormal

17
Q

trimethoprim + methotrexate =?

A

agranulocytosis!

18
Q

what to be particularly wary of in antipsychotics? CLOZAPINE

A

agranulocytosis!

19
Q

what to monitor in olanzapine?

A

fasting BM

20
Q

what to monitor in clozapine?

A

weekly FBC for 18 weeks

+ registration with a clozapine monitoring service

21
Q

what to monitor if existing CVD and starting antipsychotic Tx?

A

ECG: long QT syndrome

22
Q

monitoring requirement of amiodarone?

A

CXR (ILD) and K+ before

TFTs LFTs before treatment and then every 6 months

23
Q

what to monitor in COCP?

A

BP

24
Q

what monitoring for in carbimazole?

A

agranulocytosis!

25
Q

how to monitor tacrolimus for derm?

A

trough level

26
Q

how to monitor theophylline?

A

serum level 5 days after starting

27
Q

how to monitor cyclosporin?

A

monitor renal function

28
Q

when should statins be used with caution?

A

liver impairment (check transaminases aren’t >3x upper limit)

check ALT/AST 3 and 12 months after Tx

29
Q

how to monitor lithium?

does sodium intake affect Li+?

A

serum Li+ level 12 hours after dose (0.4–0.8), then done weekly until stable, then 3monthly (1st yr) then 6monthly

yes! Sodium depletion ↑risk of toxicity

30
Q

how to monitor Na valproate?

A

LFTs before therapy and during first 6 months (especially if at risk)

(NOT serum valproate)

31
Q

how to monitor NOAC/rivaroxaban?

A

check creatinine clearance (accurate)

can’t use eGFR (body weight, could be significantly wrong)

32
Q

dangers of NOAC Tx?

A

if you miss a tablet; not anticoagulated

must be compliant

33
Q

monitoring ciclosporin?

A

trough levels immediately before dose

34
Q

monitoring digoxin?

A

at least 6 hrs post-dose

35
Q

for gentamicin - when to increase time between, and when to change dose?

A

If the pre-dose (‘trough’) concentration is high, the interval between doses must be increased.

If the post-dose (‘peak’) concentration is high, the dose must be decreased.