Drug Interaction Flashcards
How does drug interactions occur?
When the effects of one drug care changed by the presence of another: drug, food, drink or environmental chemical agent.
What are the effects of interaction?
- Prevent correct treatment
- Cause harm/ discomfort
- Hospitalisation or death
What is interaction affected by?
Age
Race
Co-existing disease
What are the two types of interaction?
- Pharmacokinetics
- Pharmacodynamics
What are the four types of pharmacokinetics?
- Drug displacement
- Drug metabolism
- Changes in excretion
- Absorption
What are the 4 types of pharmacodynamic drug interactions?
- Changes in drug transport
- Changes in fluid/electrolyte imbalances
- Additive/synergistic interactions
- Antagonistic interactions
What are the four levels of interaction?
Severe
Moderate
Mild
Unknown
What are the two common interactions and what are their effects on your metabolism and plasma level?
Enzyme inducers: metabolism increases, plasma level decreases
Enzyme inhibitors: metabolism decreases, plasma level increases
Name two examples of enzyme inducers
Carbamazepine, barbiturate, phenytoin - 1-3wks
Name two examples of enzymes inhibitors
Ketoconazole, erythromycin, clarithromycin - 24 hours
How do you manage interactions?
- Seek alt appropriate for conditions and check interactions
- Carefule monitoring
- Adjust dose if appropriate
- Adjust administration e.g. absorption interactions - take different times
What is appropriate poly-pharmacy?
Medicines prescribed according to best evidence - complexc conditions
What is problematic poly-pharmacy?
Prescribing multiple medicines inappropriately - benefits not realised
What is poly-pharmacy?
taking more than one medicine
