Pharmacology Lecture 2_Pharmacokenetics

Question 1

Describe first order and zero order drug elimination

Answer 1

First order is typical half life elimination while zero order is a fixed amount liner decay

Question 2

Define loading dose

Answer 2

A loading dose is where you give a patient a large dose initially so you can get them into theripudic range faster.

Question 3

List some of the factors that affect the therapeutic window of drug consentations

Answer 3

Age, liver/kidney function, BMI

Question 4

What is an inducer of CYP 1A2

Answer 4

Tobacco smoke

Question 5

How do pro drugs take advantage of first pass metabolism?

Answer 5

A pro drug is an inactive form of a drug that only becomes active after it is metabolised by an enzyme in the liver.

Question 6

What are phase 2 drug metabolisim reactions

Answer 6

They are conjugation/hydrolysis rxns that add more soluable moiety

Question 7

What is an inducer and inhibitor of CYP3A4

Answer 7

Grapefruit is an inhibitor. St Johns wort is an inducer

Question 8

Define first pass metabolism

Answer 8

When a drug is absorbed from the GI tract, it will first go to the liver via the haptic portal. The liver will have a chance to metabolise the drug before it hits sestemic circulation.

Question 9

What charicteristic is required for drugs to pass the blood brain barrier

Answer 9

they must be hydrophobic (ie able to disolve through the membrane because they will not be able to difuse between cells becasue of the tight junctions in the blood brain barrier.)

Question 10

What are phase 1 drug metabolisim reactions?

Answer 10

They are redox rxns that use endogenous enzymes to uncover polar moiety

Question 11

What are the three most important phase 2 metabolism congugation rxns?

Answer 11

glucuronidation, acetylation, sulfation

Question 12

What is an inducer of CYP2E1

Answer 12

Ethanol

Question 13

Define Enteral, Parenteral, mucous membrane, and transdermal absorbtion

Answer 13

Enteral - absorbed through the GI tract
Parenteral - Injected (iv, subdermal, or intramuscular)
Mucous membrane - absorbed through MM (ie inhaler)
Transdermal - absorbed through the skin (ie nicotine patch)

Question 14

What are the 4 known zero order elimination drugs?

Answer 14

Alcohol, aspirin, warfarin, and theophylline

Question 15

What is the main consideration of protein binding?

Answer 15

When drugs with narrow therapudic windows are given to patients with albumin deficienies, the patient may need to be monitoried and the dose adjusted down because lower albumin means more free drug.

Question 16

What are the three factors of pharmacokenetics?

Answer 16

1) how is a drug absorbed into the body
2) how is a drug distributed through the body
3) how is a drug eliminated from the body

Question 17

What is the purpose of phase 1 and 2 drug metabolisium rxns?

Answer 17

reduce lipid solubility and improve bodies ability to excrete waste products.

Question 18

Define maintenance dose

Answer 18

Once the theripudic range has been reached, a maintanance does will be taken to keep drug consentrations in the theripudic window. Ideally, the dose would be such that drug consentrations flucuate within the theripudic window but never go above or below it.