 
TDM: Plasma drug
concentrations measured to determine whether therapeutic or toxic concentration
has been produced Indicated
to: - confirm
effective doses
- monitor
compliance
- investigate
possible toxicity
- monitor drugs with narrow therapeutic range
Beneficial for: - Extreme age
(extremely young or old)
- Altered
pharmacokinetics (renally, hepatically impaired, burns and ICU patients)
- Not
responding to therapy as expected after adequate doses have been given
- Exhibit
adverse effects at normal dosages
Importance of sampling time: - Accuracy crucial to ensure that drug
distribution at steady state
- Large errors in interpretation can occur if
sampling time is wrongly stated
- Except to check for toxicity, send sample for
monitoring only after the drug level achieved steady state.
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