Pharmacokinetics

Question 1

The movement of drugs in the body.

Answer 1

Pharmacokinetics

Absorption, distribution, metabolism, and excretion.

Question 2

What are the advantages to absorption with the IV route?

Answer 2

No barriers to absorption. Rapid onset, control, use of large fluid volumes, use of irritant drugs

Question 3

What are the disadvantages to absorption with the IV route?

Answer 3

High costs, difficulty, and inconvenience. Irreversibility, fluid overload, infection, embolism.

Question 4

What are the influencing factors on the rate of absorption?

Answer 4

Rate of dissolution, surface area, blood flow, lipid solubility

Question 5

Absorption IM and subcutaneous routes?

Answer 5

No significant barrier to absorption. Factors affecting the rate of absorption include water solubility (quick absorption) and blood flow to the site of the injection

Question 6

What are the advantages of absorption injections?

Answer 6

Drugs that do not dissolve completely. Drugs to be absorbed over a long period of time.

Question 7

What are the disadvantages of absorption injections?

Answer 7

Patient feels pain with each dose. Takes time and skill to avoid injury.

Question 8

Absorption oral route?

Answer 8

Barriers to absorption include the lining of the stomach. Factors that influence it are the solubility and stability of the drug, gastric and intestinal pH, gastric emptying time, food in the gut, co-administration of other drugs, special coatings on the drug preparation.

Question 9

Advantages of the absorption via the oral route?

Answer 9

Easy, convient, and no added costs. Oral medications may be retrieved if needed (inducing emesis, catharsis. Preventing absorption in to the blood stream)

Question 10

Disadvantages of the absorption via the oral route?

Answer 10

Variability, inactivation, patient requirements, local irritation

Question 11

Absorption- drug forms for oral route?

Answer 11

Chemical equivalence
Bioavailability
Difference in tablets
Enteric coated tablets
Sustained release capsules

Question 12

Absorption- additional routes of administration other than injection, IV, oral?

Answer 12

Topical (applied to surfaces for local therapy)
Transdermal (through the skin)
Inhaled
Rectal and vaginal suppository
Direct injection into specific site (intracardiac, intraarticular, intrathecal)

Question 13

Major factors that affect drug distribution?

Answer 13

Blood flow to the tissues
Ability of the drug to exit the vascular system (blood brain barrier, placenta, protein binding like albumin)
Ability of drugs to enter cells

Question 14

Also known as biotransformation. Occurs in the liver. Special considerations?

Answer 14

Metabolism.

First Pass Effect, age, nutritional status

Question 15

Possible consequences of metabolism?

Answer 15

Accelerated renal excretion of drugs, drug activation, increased therapeutic action, activation of “prodrugs,” increased toxicity, decreased toxicity

Question 16

Excretion, what are ways drugs and metabolites exit the body?

Answer 16

Urine, bile, sweat, saliva, breast milk, expired air

Question 17

Time it takes for a drug to elicit a therapeutic response.
Time it takes for the drug to reach its maximum therapeutic response.
Time that drug concentration is sufficient to elicit a therapeutic response.

Answer 17

Onset
Peak
Duration

Question 18

Medication goes from the site of administration to the blood

Medication goes from blood flow to the tissues

Answer 18

Absorption

Distribution

Question 19

The drug’s lowest plasma level

Answer 19

Trough concentration

Question 20

When a drug has a narrow therapeutic range, measuring the peak and trough concentrations can assist in what?

Answer 20

Ordering doses of the drug that will keep the plasma levels between the minimum effective concentration (MEC) and the toxic concentration.

Question 21

For drugs whose half lives are long, achieving plateau?

Answer 21

Could take days or weeks. When plateau must be achieved quickly, a large initial dose can be administered. This large initial dose is called a loading dose.

Question 22

After high drug levels have been established with a loading dose?

Answer 22

Plateau can be maintained by giving smaller doses. These smaller doses are referred to as maintenance doses.

Question 23

When a drug is discontinued how much of the drug will be eliminated from the body?

Answer 23

Most (94%) of the drug in the body will be eliminated over an interval equal to about four half-lives.