Therapeutic Drug Monitoring Flashcards
what are the factors that affect pharmacokinetics and how
- Age - drug metabolism is different for young and old people
- Weight - drug distribution in lean and obese people is different
- Sex - Hormones can affect how drugs are metabolized
- Genetics - affect the expression of genes and enzymes responsible in drug metabolism
- Disease - having an underlying disease can affect how drugs are metabolized in the body, eg. liver disease patients
- Drug Interactions - taking different drugs concurrently can affect drug metabolism
why is TDM important
[MODA]
- Monitoring - monitor adherence
- Optimize - dose optimization
- Detect - allows you to detect changes in pharmacokinetics
- Avoid - allows you to avoid drug toxicity
which drugs are suitable for TDM
- those with a narrow therapeutic range
- those with a good correlation between plasma concentration and clinical effect
- cost effective, accurate drug assay with rapid turnaround time and a small blood volume requirement.
- those where the pharmacological effect persists and is dependent on plasma concentration
- drugs with high inter-patient variability in plasma concentration
what is the meaning of therapeutic index
it refers to the range in which a drug is safe to be administered without reaching toxicity while it meets the minimum effective concentrations in the plasma
which diseased states require TDM
Renal impairments could lead to toxicity as a result of poor drug clearance
which drug requires TDM in cardiology
Digoxin
what drugs require TDM in Psychiatry
- Lithium
- Tricyclic antidepressants
what drugs require TDM in infectious disease: Antimicrobials
- Rifampicin
- vancomycin
- Amikacin
- Gentamicin
what drugs require TDM in Epilepsy
- Phenytoin
- Valprioc Acid
- Carbamazepine
why is TDM important in transplantation?
- for immunosuppressive drugs to prevent rejection while minimizing toxicity
what factors could cause lower concentration on TDM interpretation
- patient non-adherence
- rapid elimination of drug
- incorrect dose
- timing the sample incorrect
What is Lithium used for in psychiatry
To treat Bipolar disorders
what are the side effects of Lithium
- Lithium has many side-effects like tremors, polyuria, acne, hypothyroidism and many more.
- It is also potentially lethal if the blood levels are above the normal therapeutic index
what is the function of tricyclic antidepressants and what side effects do they have
- They block the re-uptake of Serotonin and Noradrenaline from the synapse.
- Their side-effects include weight gain and sedation and they are cardiotoxic and potentially lethal if taken in overdose.
