Drug and medication monitoring at Cardiff and Vale Hospitals

You might need therapeutic drug monitoring if you are prescribed medication that is easily under or over dosed. Drugs that might cause significant side effects may also be monitored. In addition, some drugs need to be monitored because the amount of drug prescribed does not correlate well with the amount that reaches the blood.

To monitor toxic effects of some medications tests such as urea and electrolytes, creatinine and liver function tests are carried out at prescribed intervals to check kidney and liver function. Monitoring can help identify decreases in the efficiency and functioning of the body in processing and eliminating the drugs.

The timing of blood collection is an important part of therapeutic drug monitoring. When you take a dose of medication, the amount in the blood rises for a period of time, peaks, and then begins to fall; usually reaching its lowest level (trough) just before the next dose. To be effective, peak levels should be below toxic concentrations and trough levels should remain in the therapeutic range.

Examples of drugs that may be monitored are: