Introduction of pharmacology Flashcards

Question

WHat are enzymes?

Answer 1

-Normal reaction inhibited and blocked by drug (substrate analogues) - enzyme inhibitor - false substrate – abnormal metabolite produced - Pro-drug – active drug produced Eg. Aspirin – pain, inflammation and clotting – blocks pain signals

Answer 2

1. Enzyme inhibitors 2. False substrates 3. Prodrugs

Answer 3

Binding site specificity (no drug acts with complete specificity) - More likelihood of non-specific interactions becoming significant with larger doses - Side effects often related to non-specific interaction (less potent effect than drug

Answer 4

1. Absorption 2. Distribution 3. Metabolism Excretion

Answer 5

Th eprocess by which drug reaches the systemic circulation Effected by – route of administration – and permeation (the absorption process)

Answer 6

Enteral administration – via gut – oral, buccaneers and rectal Parenteral administration – not via gut – injection and topical

Answer 7

pros - Oral ingestion – gut absorption - Low infection risk - Very simple for self administration cons - Harsh environment – stomach/duodenum - First pass metabolism

Answer 8

Reduced bioavailability of drug due to loss by metabolism or excretion - Intestinal lumen - Intestinal wall - Liver (main organ) - Lungs (main organ) Avoided by drug into a region of gut that does not drain into hepatic portal vein.

Answer 9

Pros – local effects, low systemic effects - Limited first pass metabolism - Low infection risk - Suited to low continuous – long period administration - Risk of systemic absorption – direct absorption to blood - Process of lipid permeation (drug must be lipid soluble, small molcular size and use a carrier molecule)

Answer 10

-Intravascular (IV, IA) – drugs enters directly into blood stream - INtramuscual r(IM) drug injected into skeletal muscle - subcutaneous (SC) – drug absorbed from subcutaneoyse tissue - dermal (ID) – dermal vascular layer - depot injection (slow release formulations)

Answer 11

Cons – high infection rapid, targeting risks Pros – rapid bioavailability for IV and IA and avoids first pass metabolism

Answer 12

Proportion of active drug that reaches the systemic circulation and is free to bind to its target Over time the plasma conc. Reduces as used up

Answer 13

- Route of administration - Formulation – enteric coating - Bioavailability is not a measure of how effective a drug is IV – rapid but short term -slow release – less absorbed but over long term

Answer 14

1.Protein binding 2. blood flow 3. membrane permeation/ tissue solubility

Answer 15

• Dynamic equilibrium for most drugs • Partly bound to plasma protein and partly in plasma water • Binding is reversible Only the UNBOUND fraction can cross membranes or bind to receptor Bound drug is locked in the plasma

Answer 16

-Diffuse through capillary walls - produce pharmacological effect - metabolised and excreted - subtle changes in binding have profound effects - particular problem in elderly amlnourished patients Bound drugs – are locked in the plasma

Answer 17

-primariy through ciculatory system - tissue perfusion rate per tissue is important

Answer 18

-Charged molecules, ions, ionised molecule diffuse less efficiently - uncharged, non-ionised drugs have better access to membrane bound compartments

Answer 19

-Phase 1 – produces toxic metabolites - Phase 2 – converts toxins to soluble metabolites for excretion Normal occur sequentially but phase 2 can precede phase 1 and can occur with the absence of phase 1

Answer 20

-Involves oxidisation, reduction and hydrolysis reactions - Chemical reactions change polarisation of substance, increase water solubility, reduce pharmacological activity and may activate prodrugs

Answer 21

Conjugation -a ding of endogenous substance 1.make water soluble and 2. biologically inactive Convert drug/toxin by covalently joining them to other molecules

Answer 22

mainly kidney and renal -Filtrtatoin - only unbound drugs, metabolites can be processed via glomerular filtration - proximal convoluted tubule cells actively secrete into nephron - reaborption of lipophilic drugs – unionised at urine pH - other routes – biliary, saliva, breat milk, sweat and tears

Answer 23

Enteropheptic circulation -principle route of excretion – kepatocyte uptake -> bile -> duodenum -> excretion in faeces But – gut can convert drug to original form – can be resabsorded across intestinal wall – re-circulate in blood and be metabolised in liver again and re-secreted into bile

Answer 24

Half life – t ½ Time taken to decrease plasma concentration to 50%

Answer 25

the movement of bile acid molecules from the liver to the small intestine and back to the liver

Answer 26

Concentration of a drug necessary to produce a given response Eg. Two drugs that bind to the same receptor may not activate it to an equal extent, one may be more potent.

Answer 27

Strength of the ligand – receptor interaction at molecular level Strong or weak binding

Answer 28

Drug ability to produce maximum possible effect when it binds to a receptor. Some drugs fully activate the receptor once they reach a suitable concentration. Full agonist – trigger max response once reach a sufficient concentration

Answer 29

trigger max response once reach a sufficient concentration