Drug Interaction

Front 1

pharmcoKINETIC interaction

Back 1

results in alteration of drug concentration at the site of action

Front 2

pharmacoDYNAMICS interaction

Back 2

result in altered activity of one drug by another

Front 3

site 1 - G1 tract

tetracycline

Back 3

tertracycline ( antibiotic)

interacts with Ca , Iron and aluminium salts.

causes insoluble complex and tetracycline effect lost

Front 4

site 1 - chloestyramine

Back 4

cholesterol reducing agent (anion exchange resin)

binds to warfarin, thyroxine and digoxin.

reduced absorption and therapeutic effect.

Front 5

site 1 - drugs increasing gastric emptying.

Back 5

metoclopramide (stimulates GI )

dopridone (anti-emetic)

causes

decreased-absorption of drugs normally absorbed in the stomach (digoxin)

increased absorption of drugs normally absobed from small instestine (tetracycline)

Front 6

site 1- drug reducing gastric emptying

Back 6

opiods (morphine)

some anti depressants.

Front 7

site 2 - plasma protein binding.

Back 7

phenytoin and sodium valproate.

phenytoin toxicity - CV collapse and CNS depression

Front 8

site 2 - plasma binding protein

Back 8

digoxin and quinidine-

digoxin toxicity - anti arryhmias, visual disturbance and GI distrubance

Front 9

site 3 - hepatic metabolism

Back 9

numerous drgs are enzymatically converted in the liver

oxidation / reduction /hydrolysis

cytochrome p450

Front 10

site 3 - drugs that increase the metabolism of others.

Back 10

some drugs induce hepatic enzymes responsible for metabolism

involves increase gene transcription and protein synthesis.

eg. barbiturates

phenytoin

carbamazepine

rifampicin (Tb and leprosy)

will reduce conc of those drug that are metabolised by that particular p450 route.

Front 11

site 3 - drugs that decrease the metabolism of other drugs.

Back 11

some drugs inhibit hepatic enzymes responsible for metabolism.

eg. erythomycin

quinoline

cimetidine

ketoconazole (anti fungal)

fluxetine/ paroxetine (anti depressant)

will increase conc of those drugs thate are metabolised by the route - potential toxicity

Front 12

site 3 - enzymes inhibitors are also present in food stuff.

Back 12

eg grapefruit juice contains psoralen (inhibits CYP3A4 isoform)

potentially significant inhibition of metabolism

>85 drugs.

carbamazepine (antiepileptic)

buspirone (5-HT1Aagonist - anxiolytic)

ciclosporin (immunosuppressant)

dihydropyridine Ca2+channel blockers (antihypertensive)

Front 13

site 3 - deliberate inhibition of metabolic enzymes

Back 13

levodopa (parkisons) --> dopamine.

eg, peripheral decarboxylase inhibitors: carbidope, denserazide with levodopa.

increase central cocn ofdopamine.

Front 14

site 3 - drugs can cause toxicity to food constituents

Back 14

tyramine - cheese , chianti wine, marmite, pickled herring. --> 4-hydroxyphenylacetic acid

eg. non selective monoamine oxidase inhibtors: tranylcypromine and phenelzine (anti depressent)

Front 15

site 4 - pharmacodynamic interactions

Back 15

classical competitive antagonist.

B2 agonis (asthma)

Non selective B agonist (hypertension)

one drug attenuates the effect of another.

Front 16

site 4 -

Back 16

ACE inhibitor (hypotension) and Ca2 channel blocking drug (nifedipine, ditiazem, verapamil)

Front 17

site 4 -

Back 17

selective serotonin reuptake inhibitors (SSRI) (fluxetine, antidepressant) and MAO inhibiotrs ( phenelzine, tranylcypromine (antidepressent)

severe CNS stimulation - delirium

Front 18

site 4 -

Back 18

aminoglycoside antibiotics ( streptomycin and kanamycin) and loop diuretics frseminde and bumetanide.

ototoxcitity - ear posioning.

hearing and blance impair.