1: Pharmacology Overview

Drug: Any chemical that can affect living processes.
* All chemicals can be considered drugs, since, when exposure is sufficiently high, all chemicals will have some effect on life.
Pharmacology: The study of drugs and their interactions with living systems.
* It encompasses the study of the physical and chemical properties of drugs as well as their biochemical and physiologic effects.
Clinical pharmacology: The study of drugs in humans.
* It includes the study of drugs in patients as well as in healthy volunteers.
Therapeutics: Also known as pharmacotherapeutics, the use of drugs to diagnose, prevent, or treat disease or to prevent pregnancy.
* The therapeutic objective of drug therapy is to provide maximum benefit with minimal harm

Effectiveness
* The most important property a drug can have.
* An effective drug is one that elicits the responses for which it is given.
Safety
* A safe drug is one that cannot produce harmful effects—even if administered in very high doses and for a very long time.
* A drug is both a remedy and a poison.
Selectivity
* Selective drug: One that elicits only the response for which it is given.
* There is no such thing as a wholly selective drug because all drugs cause side effects.
Reversible Action
* It is important that effects be reversible.
* We want drug actions to subside within an appropriate time.
Predictability
* To maximize the chances of eliciting desired responses, we must tailor therapy to the individual.
Ease of Administration
* An ideal drug should be simple to administer: The route should be convenient, and the number of doses per day should be low.
* It can enhance patient adherence and it can decrease risk.
Freedom From Drug Interactions
* When a patient is taking two or more drugs, those drugs can interact. These interactions may either augment or reduce drug responses.
* An ideal drug would not interact with other agents.
Low Cost
* Drugs should be affordable.
Chemical Stability
* Some drugs lose effectiveness during storage.
* An ideal drug would retain its activity indefinitely.
Possession of a Simple Generic Name
* An ideal drug should have a generic name that is easy to recall and pronounce.

No drug is ideal.

The drug dosage, route, and timing of administration are important determinants of drug responses.
Accordingly, the prescriber will consider these variables with care. Unfortunately, drugs are not always taken or administered as prescribed.
The result may be toxicity if the dosage is too high or treatment failure if the dosage is too low.
Poor adherence — when patients do not take medicine as prescribed.
* Patients should be given complete instructions about their medication and how to take it.

Pharmacokinetic processes determine how much of an administered dose gets to its sites of action.
Four major processes of pharmacokinetics
  * Drug absorption
  * Drug distribution
  * Drug metabolism
  * Drug excretion

Pharmacodynamics can be thought of as the impact of drugs on the body.
In most cases, the initial step leading to a response is the binding of a drug to its receptor. This drug-receptor interaction is followed by a sequence of events that ultimately results in a response.
Placebo effects also help determine the responses that a drug elicits