Pharmacotherapeutics – Drug label

Pharmacotherapeutics – Drug label (approval of a drug for a particular indication)

1. findings from clinical drug trials are submitted to FDA which oversees new drug approval in U.S.

2. information about a drug approved for a particular indication or indications is included when labeling the drug and in printed material about the drug

Pharmacotherapeutics – modification of a drug label

1. the official drug label is modified only if the drug company goes back to the FDA with additional information and requests that a new pharmacotherapeutic indication be added

2. after an official review, the FDA may decide to alter the drug label

Nonlabeled (off-label) Use Based on:

1. findings of additional research studies that are performed and reported in the professional literature

2. case reports published in the literature (nurses should not be over concerned about off-label use

Pharmacokinetics: movement of the drug inside the body and the resulting processes that occur

There are four phases:

1. absorption

2. distribution

3. metabolism

4. exretion

Pharmacokinetics – to move throughout body, drug must cross membranes in one of 3 ways:

1. first, drug molecules that are small can pass between the spaces or channels between the molecules in the membrane

2. second, drugs pass through membrane with help of a transport system (with or without energy)

3. third, drugs which are lipophilic can penetrate the membrane directly

Pharmacokinetics – factors affecting rate & completeness of absorption

1. route of administration

2. rate of dissolution

3. surface area

4. blood flow

5. lipid solubility

6. pH differences between the site of administration and the plasma

7. physiologic condition of the patient

Pharmacokinetics – Distribution depends on:

1. blood flow to tissues

2. the drug's ability to leave the blood

3. the drug's ability to enter cells

4. in healthy individuals, all tissues are well perfused, thus the drug molecules can easily be distributed throughout the body

5. scar tissue is avascular, and adipose (fat) tissue has a poor blood supply

6. abscesses and solid tumors are also avascular