Therapeutic Drug Monitoring (TDM)

Prescriber's Handbook‎ > ‎

Introduction
Manual of Electronic Therapeutic Drug Monitoring Requests
Drugs Sampling and Steady-State Time
Drugs Dosages for Adults and Paediatrics
Drugs Therapeutic Ranges
Clinical Pharmacokinetics Formulae

Introduction

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.

Electronic Therapeutic Drug Monitoring Request

Effective from 7 January 2019 onwards, all TDM requests from wards and clinics MUST be submitted via electronic through LMD order, iPesakit system. Blood samples are to be sent to Laboratory Medicine Division, Pathology Department as usual.

Please ensure electronic TDM request form is filled completely prior submission. Electronic requests and blood samples have to be submitted to Laboratory Medicine Division before 4.00 pm on working days. Any blood sample which comes after 4.00 pm will be refrigerated and processed on the following day (except weekends and public holidays). Recommendation pertaining drug doses by pharmacists will only be made after getting the results of the analysed samples.

Please refer to the attached manual for your reference:

Contacts

Ext 2926

Links

Clinical Pharmacokinetics Pharmacy Handbook

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