Pharmacodynamics Flashcards
The study of what drugs do and how they do it.
Chemicals that produce effects by interacting with other chemicals.
Pharmacodynamics
Drugs
The largest effect that a drug can produce.
The amount of drug we must give to elicit an effect.
Maximal efficacy
Potency
Special chemicals in the body that most drugs interact with to produce effects.
Receptors
What are examples of drug receptors?
Endogenous (hormones, neurotransmitters)
Enzymes
Ribosomes
Normal points of control of physiological processes. Function is regulated by molecules supplied in the body.
Receptors
All that drugs can do at receptors is mimic or block the action of the body’s own regulatory molecules.
What can’t drugs do?
Give cells new functions. Make the body do anything that it isn’t already capable of doing.
A highly desirable characteristic of a drug. Made possible by the existence of many different types of receptors.
Selectivity, the drugs can interact with one receptor and not others. The more selective a drug is, the fewer side effects.
The intensity of the response of a drug is proportional to the number of receptors occupied by that drug.
Simple Occupancy Theory
A maximal response will occur when all available receptors have been occupied.
The strength of the attraction between a drug and its receptor.
Affinity
Drugs with high affinity are very potent.
The ability of a drug to activate the receptor following binding.
Intrinsic activity.
Drugs with high intrinsic activity have high maximal efficacy and are able to cause intense response.
What does modified occupant theory involve?
Affinity and intrinsic activity
Drugs that mimic the body’s own regulatory molecules. Increase affinity and intrinsic activity.
Agonist
Drugs that block the actions of endogenous regulators. High affinity and low intrinsic activity.
Antagonist
Gives no pharmacological responses.
Mimics the actions of endogenous regulatory molecules, but they produce responses of intermediate intensity.
Partial agonist
When two drugs interact, there are what three possible outcomes?
One drug may intensify the effects of the other.
One drug may reduce the effects of the other.
The combination may produce a new response not seen with either drug alone.
Two drugs with similar actions working together.
Combined effect of drugs is higher than if given alone.
Additive effect
Synergistic effect
What five effects can food have on drugs?
Drug absorption, drug metabolism, drug toxicity, drug action, drug timing
One hour before to two hours after refers to what?
The drug not the food
The risk for a serious drug interaction is…?
Directly proportionate to the number of drugs the patient is taking. Interactions are especially important for drugs with low therapeutic indices.
How can one minimize drug-drug interactions?
Minimize the number of drugs a patient receives. Take a thorough drug history. Be aware of the possibility of illicit drug use. Adjust timing of administration to minimize interference with absorption. Monitor for early signs of toxicity. Be esp vigilant with drugs with low therapeutic indices.
