Page 188 - Interactive Theoritical Notes of Bioharmaceutics and pharamcokinetics.docx compressed

PharmD clinical pharmacy program Level 3, Semester 2 Biopharmaceutics & Pharmacokinetics (PT608(

• Genetic polymorphisms are variations in gene sequences that occur in at least 1% of

the general population.

• The enzymes that perform drug metabolism are classified as either phase I or phase II

enzymes.

 Phase I enzymes perform oxidation, reduction, and hydrolysis reactions

 phase II enzymes perform conjugation reactions.

• Polymorphisms have been reported in both phases of drug-metabolizing enzymes and

can affect the pharmacokinetic profile of a drug for a given patient.

• Understanding a patient’s genetic determinants of drug metabolism and the

consequences of these polymorphisms could be used to design optimum, personalized

dosing regimens in the clinic that would avoid adverse reactions or treatment failures

due to subtherapeutic doses.

• While this may appear perfectly logical, the redundancy of drug metabolism and

potential contribution from numerous other factors (such as diet, other drugs, age,

weight, etc) make it difficult to translate enzyme status data to a clinical decision.

• Examples of drugs with clinically important genetic polymorphisms of drug

metabolism: Warfarin, Phenytoin, Antidepressants, Antiarrhythmics, Antipsychotics,

Omeprazole, Diazepam, Sulfonamides.

Frequently asked questions

• What are the differences between pharmacogenetics and pharmacogenomics?

• How can genetic information be used to improve drug therapy for individuals?

187