Introduction to Drugs

Sources, drug evaluation, regulation, and information

Name some sources of drugs with examples

• Plants (dronabinol, digitalis/digoxin)

• Animal products (insulin from altered E. coli, thyroid hormone)

• Inorganic compounds (aluminum, fluoride, iron)

• Synthetic sources

Name the stages of drug evaluation

1. Preclinical trials

2. Phase I studies

3. Phase II studies

4. Phase III studies

5. Phase IV studies (continued evaluation)

Preclinical trial

Chemicals are tested in vitro (outside of a living organism) or in vivo (inside or on a living organism) to:

1. Determine whether they have the presumed effects in living tissue

2. Evaluate any adverse effects

Phase I study

Uses healthy human volunteers to test the drugs for safety and dosage information

Teratogenic

Chemical that causes adverse effects to a fetus

Name some reasons for dropping a chemical from a phase I study

• Unacceptable adverse effects

• Highly teratogenic

• Too toxic

• Lack of evidence of potential therapeutic effect in humans

Phase II study

Drug is given to patients who have the disease that the drug is designed to treat

Name some reasons a drug would be removed from investigation after a phase II study

• Less effective than anticipated

• Too toxic

• Unacceptable adverse effects

• Low benefit-to-risk ratio

• No more effective than other drugs already on the market

Phase III study

Drug is given to a larger sample of the population to determine the treatment benefit and monitor side effects. Drugs that finish phase III studies are evaluated by the FDA for possible approval to market.

Phase IV study

Continual evaluation after a drug is approved for marketing

Chemical name

Names that reflect the chemical structure of a drug

Generic name

Original designation that the drug was given when the drug company applied for the approval process.

Brand name

Trade name given to a drug by the pharmaceutical company that developed it. Multiple brand names may exist for the same drug.

Off-label use

Uses of a drug that are not part of the stated therapeutic indications for which the drug was approved by the FDAF

Federal Food, Drug, and Cosmetic Act

1938

Mandated tests for drug toxicity and provided means of recall, established procedures for new drugs, gave FDA enforcement power

Comprehensive Drug Abuse Prevention and Control Act

Defined drug abuse and classified drugs as to their potential for abuse, provided strict controls over the distribution, storage, and use of these drugs

Orphan Drug Act

Provided incentives for the development of drugs for treatment of rare diseases

Pregnancy Category A

Adequate studies in pregnant humans have demonstrated no risk to fetus

Pregnancy Category B

No evidence of risk to fetus in animal studies, no adequate studies in pregnant people

OR

Adverse effects in animal studies, but adequate studies in people show no risk

Pregnancy Category C

Animal studies show adverse effects on fetus, but no adequate studies in humans

OR

Benefits in humans may outweigh risks

OR
No animal reproduction studies and no adequate studies in humans

Pregnancy Category D

Evidence of human fetal risk, but potential benefits may be outweigh risksP

Pregnancy Category X

Studies in animals or humans demonstrate fetal abnormalities or adverse reactions, risk of use outweighs any possible benefit

Schedule I drug

High abuse potential and no acceptable medical use

(heroin, LSD)

Schedule II drug

High abuse potential with severe dependence liability

(narcotics, amphetamines, barbiturates)

Schedule III drug

Less abuse potential than schedule II, moderate dependence liability

(non-barbiturate sedatives, non-amphetamine stimulants, non-narcotic analgesics)

Schedue IV drug

Less abuse potential than schedule III, limited dependence liability

(some sedatives, anti-anxiety agents, non-narcotic analgesics)

Schedule V drug

Limited abuse potential, primarily small amounts of narcotics (codeine) used as antitussives or antidiarrhealsO

Orphan drug

Drug that treats a rare disease or condition but is not financially viable and thereby not produced by any drug company

Orphan Drug Act of 1983 provided financial incentives for development of these drugs

Over-the-counter (OTC) drug

Available without a prescription for self-treatment of a variety of complaints

(Advil, Tylenol, Tums, etc.)

Name some problems related to OTC drug use

• Can mask signs and symptoms of underlying disease, making diagnosis difficult

• Drug interactions and interference with prescription medications

• Adverse reactions from inactive ingredients

• Overdoses due to not taking as directed

• Patients may not consider OTC drugs to be drugs and fail to report their use

Behind-the-counter (BTC) drug

Non-prescription, but more restrictions than OTC medications. Must be kept in a secure location in the store and purchase quantities are limited.

(pseudoephedrine)

Name some sources of drug information

• Drug labels

• Package inserts

• Reference books (Physician’s Desk Reference, etc.)

• Medical journals

• Internet

List information found on a drug label

• Brand name

• Generic name

• Dosage

• Expiration date

• Special warnings

• Route of administration

Package insert

Prepared by the drug manufacturer according to strict FDA regulations, contains all of the chemical and study information that led to the approval of the drug.