PTCB - Chapter 11 - Factors Affecting Drug Activity - Definitions

Pharmacogenomics
- a field of study that defines the hereditary basis of individual differences in absorption, distribution, metabolism, and excretion (the ADME processes)

Cirrhosis
- a chronic liver disease causing loss of function

Obstructive jaundice
- an obstruction of the bile duct that causes hepatic waste products and bile to accumulate in the liver

Acute Viral Hepatitis
- an inflammatory condition of the liver caused by viruses

Hypothyroidism
- a condition in which thyroid hormone secretions are below normal, often referred to as an underactive thyroid

Hyperthyroidism
- a condition in which thyroid hormone secretions are above normal, often referred to as an overactive thyroid

Adverse Drug Reaction
- an unintended side effect of a medication that is negative or in some way injurious to a patient's health

Carcinogenicity
- the ability of a substance to cause cancer

Idiosyncrasy
- an unexpected reaction the first time a drug is taken, generally due to genetic causes

Hypersensitivity
- an abnormal sensitivity generally resulting in an allergic reaction

Anaphylactic shock
- a potentially fatal hypersensitivity reaction producing severe respiratory distress and cardiovascular collapse

Complexation
- when two different molecules associate or attach to each other

Displacement
- a drug that is bound to a plasma protein is removed when another drug of greater binding potential binds to the same protein

Enzyme Induction
- the increase in hepatic enzyme activity that results in greater metabolism of drugs

Enzyme Inhibition
- the decrease in hepatic enzyme activity that results in reduced metabolism of drugs

Additive Effects
- the summation in effect when two drugs with similar pharmacological actions are taken

Synergism
- when two drugs with similar pharmacological actions produce greater effects than the sum of individual effects

Potentiation
- when one drug with no inherent activity of its own increases the activity of another drug that produced an effect

Antidote
- a drug that antagonizes the toxic effect of another

Drug-Drug Interactions examples
- Additive effects
      trimethoprim + sulfamethoxazole for antibiotic effect
      amiodarone + dofetilide for prolongation of hearts QT interval
- Synergism
      aspirin + warfarin = increased anticoagulation (bleeding)
      vancomycin + gentamicin = increased antibacterial effects of gentamicin
- Potentiation
      amoxicillin + clavulanic acid = increased duration of amoxicillin's antibiotic effect
      penicillin + probenecid = increased duration of penicillin's antibiotic effect
- Antidote
      naloxone + morphine = relief of morphine induced respiratory depression
      vitamin K + warfarin = opposition of the anticoagulant effect of warfarin and a return to normal blood clotting time

Drug-diet Interactions
- when elements of ingested nutrients interact with a drug and this affects the disposition of the drug