Sympathomimetics Flashcards

1
Q

Drugs with sympathomimetic activity will be

A

interacting with GPCrs metaboprotpic

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2
Q

All adrenergic receptors are

A

GPCRs (alpha and beta) (metaboptropic)

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3
Q

Two main types of

A

alpha

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4
Q

three main types of

A

beta

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5
Q

Alpha 1 is associated with

A

Gq which activates phospholipase C and cleaves DAG and IP3 which both function as secondary messengers.

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6
Q

All beta receptors are associated with

A

Gs G proteins

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7
Q

Gs proteins are associated with

A

Adenyl cyclase the increased cAMP, then further activation into the cell.

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8
Q

Alpha 2 is associated with

A

Gi- which are associated with Adenyl Cylase, but they actually block Adenyl cyclase.

So, a lot of alpha 2 receptors will be expressed presynaptically and activation of these recptors will be inhibitory and block a lot of things.

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9
Q

Alpha 2 is less common in

A

periphery , but can be found in the CNS.

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10
Q

Phenylephrine and methoxamine

A

(alpha agonist ) a1>a2»»»»»B (almost none to beta)

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11
Q

Norepinephrine

A

(mixed) a1=a2; B1»B2

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12
Q

Epinephrine

A

(mixed)a1=a2; B1=B2 this activates all alphas and all betas and is why can be a lifesaving drug. Released from adrenal medulla so it gets distributed in the entire system and effects all its receptors.

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13
Q

Dobutamide

A

B1>B2»»>a this is a beta agonist

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14
Q

Isoproterenol

A

B1=B2»»>a (beta agonist )

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15
Q

Albuterol, terbutaline, metaproterenol

A

B2»»B1»»>a (beta agonist) mostly beta 2

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16
Q

Dopamine

A

D1=D2»B»a (dopamine agonist )

17
Q

Fenoldopam

A

D1»D2 (dopamine agonist)

18
Q

If treating a condition that is specific to beta , you want to be more

A

selective

19
Q

Catchcholamines with two hydroxyl groups on the molecule

A

norepinephrine

epinephrine

isoproterenol

dopamine

“DINE”

won’t have CNS effects because they are polar

20
Q

Noncatecholamines sympathomimetics

A

phenylephrine

ephedrine

amphetamine

metamphetamine

these do have CNS effects

“MEAP”

21
Q

What effects do noncatecholamines sympathomimetics have on the periphery?

A

increase BP

increase heart contractions

increase risk of MI

does this because it affects receptors on the periphery.

22
Q

Alpha 1 effects which organs

A

Most vascular smooth muscle (innervated)

Pupillary dilator muscle (contraction dilated pupils)

Pilomotor smooth muscle (hair)

Prostate (contraction)

Heart (increase force of contraction)

23
Q

Beta 1 effects

A

heart, juxtaglomerular cells (increases force and rate of contraction; increases renin release)

24
Q

Beta 2 effects

A

Respiratory, uterine, and vascular smooth muscle (promotes smooth muscle relaxation)

Skeletal muscle (promotes potassium uptake)

Human liver (activates glycogenolysis)

25
Q

Beta 3 effects

A

bladder ( relaxes detrusor muscle)

fat cells (activates lipolysis)

26
Q

D1 effects

A

smooth muscle (dilates renal blood vessels)

27
Q

D2 effects

A

nerve endings (modulates transmitter release)

28
Q

These receptors are extremely highly expressed in the heart

A

Beta 1

29
Q

So, if epi /ephidrine is used, it will activate all receptors and cause contraction

A

this is desired with anaphylaxis

30
Q

Nasal spray contains

A

alpha 1 agonist which causes vasoconstriction

same principle is used to stop eye watering

31
Q

Alpha one agonist can

A

raise BP

32
Q

Nasal sprays are contraindicated in patients with

A

high blood pressure because they contain alpha 1 agonist which can raise blood pressure even more

33
Q

Alpha 1 decongestants are prohibited with prostate hyperplasia, why?

A

Because they cause contraction of the prostate gland which can squeeze the urethra and cause problems.

34
Q

Activation of Beta 1 ?

A

causes increase force and rate of contraction.

If force and rate increases then it requires more oxygen which could lead to MI in patients with atherosclerosis

35
Q

Isoproterenol activates ?

A

B1=B2 and is used to induce MI in model organisms because it increases the force of contraction requiring the heart to need more oxygen which leads to MI, so B1 agonist is not used very often.

36
Q

Beta 2 receptors are very common in

A

respiratory tract, uterus, and vascular and smooth muscles

Drugs that activate B2 promote smooth muscle relaxation which is desired in the respiratory tract.

37
Q

B2 agonist are used to treat

A

Asthma because they instantly open up the airway by activating B2 receptors. Also sometimes used to stop premature labor.

38
Q

When treating asthma, you want to be sure that the drug is very

A

selective for B2 because you do not want to activate B1, otherwise you would increase BP and increase cardiac demand.

It is almost not possible to be this selective, so B2 agonist are contraindicated in patients with HTN or remarkable cardiac history such as (MI)

So, how do we treat these patients with asthma?

We go on the fact that apart from adrenergic receptors, we also have muscarinic receptors in our airways, so instead of a B2 agonist, we could use cholinolytics because these will cause bronchodilation whereas cholinomimetics will induce bronchoconstriction.