Chapter 1 (Orientation to Pharmacology)

Question 1

“The Big Three”

-the most important characteristics that any drug can have

Answer 1

1. Effectiveness (an effective drug is one that elicits the responses for which it is given)
2. Safety (a safe drug is one that cannot produce harmful effects)
3. Selectivity (a selective drug is one that elicits only the response for which it is given; there is no such thing because all drugs have side effects)

Question 2

Drug

Answer 2

Any chemical that can affect living processes.

By this definition, virtually all chemicals can be considered drugs, since, when exposure is sufficiently high, all chemicals will have some effect on life.

[Accordingly, rather than discussing all drugs, we will focus primarily on drugs that have therapeutic applications.]

Question 3

Pharmacology

Answer 3

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.
-In addition, pharmacology includes knowledge of the history, sources, and uses of drugs as well as knowledge of drug absorption, distribution, metabolism, and excretion.]

Question 4

Clinical Pharmacology

Answer 4

The study of drugs in humans.

[This includes the study of drugs in patients as well as in healthy volunteers (during new drug development).
-encompasses all aspects of the interaction between drugs and people. The primary interest is the use of drugs to treat patients in clinical pharmacology.]

Question 5

Therapeutics

Answer 5

The use of drugs to diagnose, prevent, or treat disease or to prevent pregnancy.
[Alternatively, therapeutics can be defined simply as the medical use of drugs.
-Therapeutics is our principal concern.]

Question 6

Additional Properties of an Ideal Drug

There are 7 more

Answer 6

1. Reversible Action
2. Predictability
3. Ease of Administration
4. No Drug Interactions
5. Low Cost
6. Chemical Stability
7. Simple Genetic Name

Question 7

Reversible Action

Answer 7

Important that effects be reversible. We want drug actions to subside within an appropriate time. For example, general anesthetics would be useless if patients never woke up. Some drugs we do NOT want reversibility, like antibiotics, we want toxicity to microbes.

Question 8

Predictability

Answer 8

Patients are unique, accuracy of how a patient will respond is not guaranteed. Therefore, we must tailor therapy to each individual to maximize the chances of eliciting desired responses.

Question 9

Ease of Administration

Answer 9

Increases convenience of administration and patient adherence, while reducing medication errors.
The route should be convenient, and the number of doses per day should be low.

Examples:

• Patients with diabetes, who must inject insulin multiple times a day, are not likely to judge insulin ideal. Similarly, nurses who must set up and monitor IV infusions are unlikely to consider intravenous drugs ideal.
• Patients are more likely to adhere to a dosing schedule that consists of one daily dose rather than several. Furthermore, whenever skin integrity is broken, as is the case when drugs are given by injection, there is a risk of infection as well as injection-site pain and discomfort.

Question 10

Freedom from Drug Interactions (No Drug Interactions)

Answer 10

An ideal drug would not interact with other agents. When a patient is taking two or more drugs, those drugs should not interact.

[Because of the potential for interaction among drugs, when a patient is taking more than one agent, the possible impact of drug interactions must be considered.]

Question 11

Low Cost

Answer 11

An ideal drug would be easy to afford. The cost of drugs can be a substantial financial burden.

[As an extreme example, treatment with adalimumab [Humira], a drug for rheumatoid arthritis and Crohn’s disease, can cost $50,000 or more per year. More commonly, expense becomes a significant factor when a medication must be taken chronically. For example, people with hypertension, arthritis, or diabetes may take medications every day for life. The cumulative expense of such treatment can be huge—even for drugs of moderate price.]

Question 12

Chemical Stability

Answer 12

An ideal drug would retain its activity indefinitely.
However, some drugs lose effectiveness during storage. Others that may be stable on the shelf can rapidly lose effectiveness when put into solution (eg, in preparation for infusion). These losses in efficacy result from chemical instability. Because of chemical instability, stocks of certain drugs must be periodically discarded.

Question 13

Simple Generic Name

Answer 13

An ideal drug should have a generic name that is easy to recall and pronounce

[Generic names of drugs are usually complex, and hence difficult to remember and pronounce. As a rule, the trade name for a drug is much simpler than its generic name.]

Question 14

The Therapeutic Objective

Answer 14

The objective of drug therapy is to provide maximum benefit with minimal harm.

[If drugs were ideal, we could achieve this objective with relative ease. However, because drugs are not ideal, we must exercise skill and care if treatment is to result in more good than harm.]

Question 15

Intensity of response

Answer 15

Our ultimate concern when administering a drug is the intensity of the response. The intensity of response is determined by the concentration of a drug at its site of action.

Question 16

Three Factors That Determine the Intensity of Drug Responses

HINT: Multiple factors determine how an individual will respond to a prescribed dose of a particular drug. By understanding these factors, you will be able to think rationally about how drugs produce their effects.

Answer 16

1. Administrations (med errors, patient adherence)
2. Pharmacokinetics (absorption, distribution, metabolism, excretion)
3. Pharmacodynamics (drug-receptor interaction, patient’s functional state, placebo effect)

Question 17

Pharmacokinetics
(What is it and what are the four main processes)

HINT: Collectively, these processes can be thought of as the impact of the body on drugs.

Answer 17

Pharmacokinetic processes determine how much of an administered dose gets to its sites of action.

There are four main pharmacokinetic processes:

(1) drug absorption,
(2) drug distribution,
(3) drug metabolism, and
(4) drug excretion.

Question 18

Pharmacodynamics

HINT: This process can be thought of as the impact of drugs on the body.

Answer 18

Once a drug has reached its site of action, pharmacodynamic processes determine the nature and intensity of the response. The impact of drugs on the body and the initial step leading to a response is the binding of a drug to its receptor.

[The patient’s functional state can influence pharmacodynamic processes i.e. the patient can develop a tolerance to the drug.]

Question 19

Chapter 1 - Key Points ( 6)

Please note, that the ideal medication exists in theory only: In reality, there’s no such thing as a perfect drug. To approach perfection, our drug should have certain properties, such as effectiveness and safety. In the discussion below, we consider these two characteristics as well as others that an ideal drug might have.

Answer 19

1. The most important properties of an ideal drug are effectiveness, safety, and selectivity.
2. If a drug is not effective, it should not be used.
3. Drugs have both benefits and risks.
4. There is no such thing as a wholly selective drug: All drugs can cause side effects.
5. The objective of drug therapy is to provide maximum benefit with minimum harm.
6. Because all patients are unique, drug therapy must be tailored to each individual.