DRUG INTERACTIONS WITH RECEPTORS AND ION CHANNELS Flashcards Preview

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Flashcards in DRUG INTERACTIONS WITH RECEPTORS AND ION CHANNELS Deck (36):
1

Acetyl-beta-methylcholine/methacholine

1 - NACHR agonist.
2 - inactive negative isomer has no affinity.

2

adenosine

1 - Targets the A1 receptor linked to the Kach channel by inhibiting adenylyl cyclase and hence increasing K efflux.
2 - slows HR
3 - can terminate some dysrhythmias
3 - inhibits renin release via A1R.

3

atropine

1 - MACHR anatagonist nonselective
2 - sympathomimetic effects as it inhibits parasympathetics
3 - tertiary ammonium
4 - from deadly nightshade
5 - mydriasis (dilates pupils)
6 - prolonged action (1 hr ish)

4

Bay K 8644

1 - Dihydropyridine (DHP) calcium agonist.
2 - highly lipid soluble - aromatic.
3 - accesses Ca channel via lipid phase of the membrane.
4 - favours mode 2 channel gating - prolonged opening.
5 - opens L type Ca channels.

5

Benzilylcholine mustard

1 - irreversible alkylates the MACHR. sympathomimetic.
2 - an ethylamine

6

benzocaine

1 - ester local anaesthetic . uncharged so rate and extent of block are independent of pH.
2 - long lasting.

7

alpha-bungarotoxin

1 - a neurotoxin of the taiwanese banded Krait. irreversibly inhibits the NACHR causing paralysis, respiratory failure and death.

8

cholera toxin

1 - ADP-ribsoylates Gαs, inhibits GTPase hence prolonged activation.

9

danazol

1 - Progestagen (progesterone) antagonist
2 - modified derivative of testosterone.
3 - initially used to treat endometriosis (cells from the lining of the uterus (endometrium) appear and flourish outside the uterine cavity, most commonly on the peritoneum which lines the abdominal cavity)
4 - causes decreased secretion of estradiol

10

diazoxide

1 - opens pd sensitive K channel
2 - inhibits insulin release so not only used to treat hypertension (but only in a hypertensive emergency) but also hypoglycaemia as a result of an insulinoma.

11

diltiazem

1 - blocks L type Ca channel but distinct site to DHP. enhances their binding.
2 - greater use dependence and more prolonged than DHPs.
3 - preferential to cardiac hence antidysrhytmic (type 4), Acts preferentially at the nodes where the AP depends upon the L and T type current hence slowing conduction.
4 - a benzothiazepine.
5 - more effect on S.M. than verapamil.
6 - well absorbed by GI, extensively metabolised.
7 - side effects - flushing and headache,

12

d-tubocurarine

1 - NACHR antagonist
2 - active ingredient of curare

13

ethinylestradiol

1 - estrogen (estradiol) agonist.
2 - orally bioactive and used in many combined oral contraceptive pills

14

fludrocortisone

1 - Mineralocorticoid (aldosterone) agonist.
2 - replace aldosterone in adrenal insufficiency ie addisons and congenital adrenal hyperplasia.

15

glibenclamide

1 - closes Katp channel via sulphylurea receptor.
2 - orally acting hypoglycaemic used to treat T2D.
3 - weight gain side effect. well absorbed. excreted so action enhanced in elderly.

16

isoprenaline

1 - β-adrenoceptor agonist
2 - inactive d isomer has affinity
2 - treat bradycardia

17

lidocaine

1 - local anaesthetic, pd gated Na channels.
2 - pKa 8-9
3 - stabilises inactivated state by blocking channel
4 - an amineester
5 - neutral crosses membrane, protonated form blocks.
6 - inhibits C and Aδ fibres first
7 - use dependent for high rates of stimulation. class 1b antidysrhythmic w/ v.fast association/dissociation.
8 - neuropathic pain.
9 - amides metabolised in the liver.
10 - increases proportion of inactive channels at any pd.

18

lithium

1 - noncompetitively inhibits phosphatase for IP1 to inositol and hence blocks inositol recycling. imp in brain as no uptake of I through BBB
2 - used to treat manic depression

19

mifepristone

1 - Glucocorticoid (cortisol) antagonist
also a progesterone antagonist so used as an abortifacient in first 49 days.

20

minoxidil

1 - pd gated K channel opener.
2 - vasodilate hence hypertension.
3 - side effect of hirsutism, hence treat alopecia.

21

muscarine

1 - MACHR agonist
2 - from fly agaric mushroom

22

nicorandil

1 - pd sensitive K channel opener.
2 - also NO donor.
3 - vasodilate to treat angina (and hypertension).

23

nicotine

1 - NACHR antagonist

24

nifedipine

1 - DHP L type antagonist.
2 - aromatic, highly lipid soluble, accesses channel via lipid phase.
3 - favours mode 0, closed.
4 - Causes peripheral and coronary vasodilation hence treats hypertension and angina.
5 - causes reflex tachycardia.
6 - more active on vascular Ca channels as inactive channels dominate due to the less negative resting pd.
7 - usually combined with a β blocker to combat reflex tachycardia.

25

norethisterone

1 - progestagen (progesterone) agonist.
2 - some contraceptives. to treat painful/irregular/heavy periods

26

pertussis toxin

ADP-ribosylates Gαi inhibiting its action.

27

prednisolone

1 - Glucocorticoid (cortisol) agonist
2 - to treat a wide range of inflammatory and autoimmune diseases by modulate transcription for various genes inc reducing COX-2 cytokines, iNOS and cell adhesion molecules.

28

procaine

1 - ester local anaesthetic pKa 8-9
2 - broken down by BuChE
3 - inhibit C and Aδ fibres first

29

quinidine

1 - intermediate rate of association/ dissociation.
2 - stereoisomer of quinine.
3 - class 1a antidysrhythmic (first group classified hence nomenclature), increases AP duration.

30

QX 314

1 - quaternary amine local anaesthetic. pd gated Na channel blocker.
2 - charged so cant cross membrane.
3 - amides metabolised in liver.

31

spironolactone

Mineralocorticoid (aldosterone) competitive antagonist. also antiandrogenic.
2 - primary use as a potassium sparing diuretic.

32

tamoxifen

1 - estrogen (estradiol) antagonist.
2 - treat braest cancer

33

tetrodotoxin

1 - toxin with guanidinium groups. blocks pd gated Na channels from the outside.
2 - no use dependence.
3 - from japanese pufferfish.
4 - works exclusively from the extracellular side.

34

tolbutamine

1 - closes Katp via sulphonylurea R.
2 - orally acting. depolarises pancreatic beta cell, opens pd gated Ca channel, Ca in causes exocytosis.

35

tyrphostins

1 - inhibit tyrosine kinases, interest in controlling neoplasic growth.
ie imatinib for chronic myelogenous leukaemia.

36

verapamil

1 - blocks L type channels. a Phenylalkylamine.
2 - binds distinct site to DHPs and reduces their binding.
3 - D600 is its derivative.
greater use dependence and longer action than DHPs
4 - preferentially blocks cardiac over vascular hence a class 4 antidysrhythmic. Acts preferentially at the nodes where the AP depends upon the L and T type current hence slowing conduction.
5 - slows HR.
6 - constipation side effect