Managing drug interactions

Question 1

Define drug interaction

Answer 1

• An interaction occurs when the effects of one drug are changed by the presence of another drug, food, drink,
  or an environmental chemical agent

Question 2

Define an adverse reaction

Question 3

What are usually the three main categories of an adverse reaction

Answer 3

1. Adverse (undesirable) - toxic and reduces efficiency
2. Beneficial
3. No clinical significance

Question 4

Name at least five drugs with a narrow therapeutic index - so likely to cause problems

Answer 4

Question 5

A combination of a narrow therapeutic index drug with an X is likely to be a problem

Answer 5

A combination of a narrow therapeutic index drug with an enzyme inducer/inhibitor is likely to be a problem

Question 6

How can pharmacodynamic interactions cause adverse effects - what are the two types of these

Answer 6

• Interactions where the effects of one drug is/are changed by the presence of ANOTHER drug at its site of action
• Competition for receptor OR interference with physiological systems

Question 7

Pharmacokinetics interactions as a cause of adverse effects

Answer 7

• Effected by the process in which drugs are absorbed, distributed, metabolised, excreted ADME

Question 8

Name four ways to manage drug interactions

Answer 8

1. Avoid combination - if hazards outweigh benefit
2. Adjust dosing - e.g. in the pic
3. Monitor the patient - e.g. blood drug level, bp
4. Continue medication as before - if interactions arent significant