B4 When drugs dont work

Question 1

Why is Therapeutic Drug Monitoring important

Answer 1

• ensures drugs work properly
• achieve correct dose of drug in patients
• gain max therapeutic benefit
• prevent unwanted side effects

Question 2

Processes prior to therapeutic drug monitoring

Answer 2

Correct dose determined from formula: weight, age, surface area
Doses in/decreased based on clinicians interpretation
Formula not idea for patients on other drugs, dialysis for poor kidney function
Hard to adjust drugs if patient compliance is low

Question 3

Explain Flourescent Polarisation Immunoassay (FPIA)

Answer 3

• Polarised light is used to excite a fluorescent label on a drug
• Homogenous (no washing steps), competitive assay
• Use restricted to molecules with MW <20,000
• Includes Insulin, Cortisol, hCG, Drugs (Digoxin, Theophyline & Gentamycin)

Requires

• Fluorescently labeled Drug
• Antibody to Drug
• machine (TDxFLxｨ System)

Question 4

FPIA control one: Drug with Fluorescent label

Answer 4

Fluorescent Polarisation Immunoassay

Light causes the free drug to spin. Polarisation is therefore lost in emitted light

Question 5

FPIA control two: Drug with Fluorescent label Antibodies that bind drug

Answer 5

As drug is bound w/ Ab it is prevented from spinning. (as too large) Polarisation is therefore kept

Question 6

FPIA Sample 1: Drug with Fluorescent label Antibodies that bind drug
Sample containing high drug concentration

Answer 6

Non-labelled drug binds Ab leaving drug free to rotate

Polarisation is therefore lost

Question 7

FPIA Sample 2: Drug with Fluorescent label Antibodies that bind drug
Sample containing low drug concentration

Answer 7

Not sufficient unlabelled drug to bind Ab therefore labelled drug also bound by Ab & does not rotate
Polarisation is therefore conserved