Drug-Drug Interactions Flashcards
What is a Drug-Drug interaction?
Two or more drugs that interact to create an action that is not the normal action of one
What drugs are commonly involved in drug interactions?
Warfrin Lithium Digoxin Cyclosporin Phenytonin Gentamicin
What factors increase the likelihood of a drug interaction from happening?
High number of medications Young or old Critically ill patients patients undergoing surgery Chronic condition sufferers
What are the three mechanisms of drug interactions?
Pharmaceutical
Pharmacokinetic
Pharmacodynamic
Why does pH affect absorption of a drug?
pH determines ionization which determines what molecules get through the cell membranes
What is the effect of broad spectrum antibiotics on normal gut flora?
Destroys normal gut flora
Where are the majority of oral medicines absorbed?
In the small intestine
What is the rate limiting step in oral drug absorption?
Gastric emptying
when does protein binding displacement occur?
when there is a reduction in the extent of plasma protein binding of a drug caused by the presence of another drug
What does displacement of a drug from plasma proteins result in?
Increased bioavalability of the displaced drug
When do drug interactions involving metabolism occur?
When a drug inhibits the metabolism of another
Where does drug elimination occur?
The kidneys
What are the effects of lop diuretics?
Increase in tubular reabsorbtion
What are synergistic interactions?
When two drugs with the same affect are given together
