Chap 5 Pharmacology

Question 1

Describe the THREE (3) categories of drugs

Answer 1

1) Over-the-Counter Drugs
- No purchase restriction by FDA, but kept behind the pharmacy counter
2) Prescribed Drugs
Determined unsafe for OTC purchase because of possible harmful side effects if taken indiscriminately
(e.g. birth control pills, antibiotics, hormones
3) Controlled drugs
Drugs controlled by stricter prescription requirement and legal control because of the danger of addiction or abuse

Question 2

Pharmacokinetic is the movement of drugs within the body. Briefly describe the
FOUR (4) processes involved in pharmacokinetic

Answer 2

1) Absorption – Passage of drug through a membrane into the
bloodstream.
2) Distribution – Drug movement from the bloodstream into the tissues and
fluids of the body.
3) Metabolism – Physical and chemical alterations that the drug undergoes
in the body.
4) Excretion – Elimination of waste products of drug metabolism from the
body.

Question 3

Discuss the THREE (3) major factors that affect drug absorptions

Answer 3

pH (1 mark)
- Drugs of a slightly acidic in nature (e.g. aspirin) are absorbed well within
the acidic stomach environment. (1 mark)
-Drug of an alkaline pH are not absorbed well through the stomach wall but
are readily absorbed in the alkaline environment of the small intestine. (1
mark)
ii. Route of the Administration(1 mark)
- For IV delivery, absorption is complete; that is, the total dose of drug
reaches the systemic circulation. (1 mark)
- The oral route requires that a drug dissolves in the GI fluid and then
penetrates the epithelial cells of the intestinal mucosa. (1 mark)
- This may result in only partial absorption and, thus, lower bioavailability. (1
mark)
iii. Presence or absence of food in the stomach (1 mark)
- Food in stomach tend to slow down absorption due to slower emptying of
the stomach. (1 mark)
- If a fast drug effect is desired, an empty stomach will facilitate quicker
absorption. (1 mark)
- On the other hand, medications that are irritating to the stomach can be
buffered by the presence of food. (1 mark)

Question 4

List the 5 routes of administration

Answer 4

• oral
• intravenous
• subcutaneous
  -intramuscular
• other routes of administration

Question 5

List the 7 factors that affects bioavailability

Answer 5

Route of administration
Drug interactions
Food interactions
Rate of metabolism
Health of the GI tract
Age of the patient
Disease stage

Question 6

List the 5 factors that affect drug distribution

Answer 6

Drug molecular size
Rate of blood flow
Lipid Solubility
Anatomical & physiological nature of biological spaces, e.g. blood brain barrier
Disease state

Question 7

List the 5 factors affecting drug metabolism

Answer 7

-Hepatic blood flow
-Drugs which alter liver enzymes
-Liver disease
-Genetic factors
-Age

Question 8

List the 5 routes that drugs can be excreted

Answer 8

-Kidneys as urine
-GI tract as faeces
-Lungs as exhaled air
-Breast milk
-Perspiration

Question 9

Explain the consequences if excretion does not occur properly

Answer 9

-If drug is not excreted properly before repeated doses are given, drug accumulation may occur
-Drug accumulation may occur in the patient with decreased kidney function
-If unnoticed, the accumulative effect may build to a dangerous or toxic level
-Toxicity can be resulted from exposure to dangerous amount of drug that normally safe when given in a smaller amount

Question 10

State the 3 factors affecting drug excretion

Answer 10

Age
Kidney function
Drug Molecular weight

Question 11

List the 4 classes of receptors

Answer 11

Intracellular receptors
Transmembrane enzymes
Ion channels
G protein coupled receptor

Question 12

State the difference between agonist vs antagonist

Answer 12

Agonist binds to a receptor site and causes a response.
Antagonist works against the drug and blocks the response.

Question 13

Describe how liver affects metabolism function

Answer 13

Drugs are mostly metabolized in the liver
Drugs are broken down and altered into more water-soluble by-products (metabolites), so that they may be more easily excreted by the kidneys.
In liver disease patient, drugs are not being broken down properly by the inefficient liver
The unchanged drug may accumulate the liver and unable to pass out of the body’s excretory system
Patient may exhibit toxic effects of a drug or drug may not work as intended

Question 14

List the conditions that may hamper absorption

Answer 14

Incorrect administration may destroy the drug before it reaches the bloodstream or the site of the action

Question 15

List the conditions that may hamper distribution

Answer 15

Poor circulation (impaired flow of blood) may prevent the drug from reaching the tissue

Question 16

List the conditions that may hamper metabolism

Answer 16

Damaged liver may prevent adequate breakdown of the drug, thus causing a build-up of unmetabolized drug

Question 17

List the condiitons that may hamper excretion

Answer 17

Kidney failure may prevent passage of drug waste products, thereby causing an accumulation of the drug in the body