Sympathomimetic Drugs/ Adrenoceptor Agonist Flashcards
Receptors present in somatic motor neuron terminals
Beta 2 adrenergic
Which receptors binds only to epinephrine
Beta 2 adrenergic receptor
Beta 1 location and function
Fat cells
Lipolysis
D1 location and function
Splanchnic and renal blood vessel
Relaxation of vacuolar smooth muscle->Dilation - Dec peripheral vascular resistance
D2 receptor
On presynaptic nerve terminals
F: inhibits NE, inhibit adenylyl cyclase, open K channels and influx of Ca
Beta 3 receptor
Lower affinity
Beta 3 resistance to desensitization> beta 1 and 2
Epi has increase activity at which receptors
Beta 2
NE is potent at which receptors
Alpha 1 and beta 3
Clinical use of phenylephrine and metoxamine
- vasoconstrictor
- tx hypotension
- nasal decongestant
- mydrasis
Alpha 1 agonist
Phenylephrine, Metoxamine ( not cathecol derived- not affected by COMPT)
Milodrine (activated- desglymilodrine)
Xylometazoline
Oxymetazoline( high doses cause hypotension due to clonidiine like effect)
Alpha 2 action
- on presynaptic terminal - -ve feedback for NE
- ## Hypotension
Effect of clonidiine
Acts on alpha 2 receptor in brainstem
Hypotension and bradycardia
Action of methyldopa
- antihypertensive
- high doses stimulate postsynaptic vascular alpha 2 receptor-> vasoconstriction and increase BP
Alpha 2 agonist drugs
Clonidine Guanabenz Guanfacine Methyldopa Moxonidine
If alpha 2 drugs withdrawn to quickly
Cause withdrawal symptom’s, and rebound hypertension
Tx of orthostatic hypertension
Midodrine
Side effects of alpha 2 drugs
- sedation
- dry mouth
- sleep disturbance
- sexual dysfunctions in males
- nausea
- dizziness
Drugs that act on Beta 1 and 2 receptors
Isoproterenol
Beta 1 selective drug
Dobutamin
Beta 2 selective drugs
Albuterol
Terbutaline
Ritodrine
Metaproterenol
Clinical use it epinephrine
- tx for anaphylaxis
- use along with anesthetic -> cause vasoconstriction -> Dec absorption-> prolonging anesthetic
Mixed alpha and beta agonist
- norepinephrine (tx septic shock)
- epinephrine
- phenylpropanolol
- ephedrine
- pseudoephedrine
Phenylpropanolamine
Mixed adrenergic agonist Vasoconstriction Shrink mucosal surface Otc apatite suppressant Associated with hemorrhagic stroke
Phenylpropanolamine
Mixed adrenergic agonist Vasoconstriction Shrink mucosal surface Otc apatite suppressant Associated with hemorrhagic stroke
Pseudoephedrine
Mixed adrenergic agonist
Decongestant
Use of ephedrine
- asthma therapy
- increase skeletal muscle tone-> M. Gravis
- tx narcolepsy
- nasal decongestant
- promote weight loss
Amphetamine like drugs
- amphetamine
- modafinil
- methylphenidate
- phenmetrazine
- tyramine
- methamphetamine
Amphetamine roles
- CNS stimulant
- appetite suppressant
Tx ADHD
amphetamine like drug: METHYLPHENIDATE
Function of modafinil
- inhibit NET and DAT-> increase synaptic NE, dopamine, serotonin, and glutamate
- decrease GABA
Indirect sympathomimetic drug used for Tx of narcolepsy
MODAFINIL
Tyramine present in what foods
Cheddar cheese Maramite Wine Country ham Fava beans
Patients treated with Mao inhibitors should avoid tyramine containing foods why
(Mao metabolises tyramine)
Mao inhibitors -> increased effects of tyramine-> hypertension
Catecholamine reuptake inhibitors ( Indirect sympathomimetic)
TCA -imipramine Atomoxitine, reboxitine Sibutramine Duloxitine Cocaine
Is an NE and serotonin reuptake inhibitors cause side effects of orthostatic tachycardia and used to treat urinary incontinence
TCA- imipramine
NET inhibitor used to treat ADHD
Atomoxitine
Drugs used to treat ADHD
- Methylphenidate (amphetamine like)
2. Atomoxitine (NET inhibitor)
Serotonin and NE reuptake inhibitor used to as appetite suppressant in obesity
Sibutramine
Function and use of duloxitine
- NE and serotonin reuptake inhibitor
- antidepressants
- Treat fibromyalgia ( musculoskeletal pain)
Cocaine effects
Sympathomimetic inhibiting reuptake of NE and especially dopamine in the CNS Effects: - increase vasoconstriction - hypertension - angina pectoris - mucosal rupture
Central anti-adrenergic
They are alpha 2 agonist of CNS: Clonidine Guanabenz Guanfacine Methyldopa ( alpha methylnorepinephine)
Function of central anti adrenergic
Dec sympathetic outflow from CNS
cause orthostatic Hypotension
Clonidine- can also cause rebound HPT, sedation
Peripheral presynaptic adrenergic
Dec NE->Dec bp, orthostatic Hypotension, increase GI motility, Dec urinary retention, bradycardia
Guanethidine - increase infusion-> Dec NE
Guanadrel- same
Bretylium-same and used as antiarrhythmics
Reserpine- block VMAT
Postsynaptic alpha antagonist
Phentolamine Phenoxybenzamine Prazosin Doxaosin Terazosin Tamsulosin
Phentolamine function and use
Antagonist of alpha 1 and alpha 2 - Dec PVR - hypotension - antagonises effect of serotonin - reflex cardiac stimulation ( angina pectoris, arrhythmia) Uses:. 1.Tx pheochromocytoma 2. Tx cocaine toxicity 3. Tyramine toxicity in patients tx w/ MAO inhibitor
Side effects of chronic use of phentolamine
Abdominal cramping
Ulceration
Diarrhea
Phenoxybenzamine action and function
Is no reversible Acts on both alpha 1and 2 receptors present on postsynaptic and presynaptic terminal
- cause dec in vasoconstriction
- orthostatic Hypotension
- tx for pheochromocytoma
Prazosin action, uses, side effects
Antagonist Acts on alpha 1 receptors
- orthostatic Hypotension
- reflex tachycardia
Use:1. tx for PTSD
- Tx hypertension
- Tx CHF
effects: 1.can cause Prazosin Syncope
2. Chronic use reduce efficacy
Terazosin and doxazosin use
Alpha 1 Antagonist used to tx BPH
Tamsulosin features and use
Alpha 1 Antagonist with high BA and t1/2 9-15hrs
Inhibit contraction of prostate-> tx BPH
Alpha 2 antagonist
Yohimbine
Mert something check sketchy
Action of yohimbine and use
Alpha 2 antagonist, blocks alpha 2 receptors in medulla in CNS and presynaptic terminal in the periphery -> increase NE release
- Increases BP
- aphrodisiac- tx ED
Quinazoline derivative and use
Prazosin (piperazinyl quinazoline)
Silodosin
Alfuzosin
Indoramin
Tx: BPH
And increase risk of prolonged QT
Labetalol
Alpha 1 and beta antagonist
Chlorpromazine and haloparidol
Act at dopamine receptor and alpha receptor antagonist
Ergot derivatives: ergotamine and dehydroegrotamine
Reversible alpha receptor blockage-> partial agonist effect
Pharmacokinetics of beta antagonist drugs
- Increase absorption by oral route
- Low BA
- Rapid distribution-> large Vd
Actionof beta blockers
- Dec heart rate and contractility and BP
- Increase resp tone
- Anti arrhythmic
- Tx angina pectoris (Dec heart O2 demand), cardiac obstructive hypertrophy,
- Tx thyrotoxicosis, anxiety, migraine
- Local anesthetic
- Antihypertensive (Dec renin)
- Aortic dissection
- Long term use-> Dec mortality in MI, myocardial arrhythmias
- Dec lipolysis, gluconeogenesis-> hypoglycemia ( tx with glucagon)
Side effect of beta blocker
- Worsen heart failure
- Dec AV conduction
- Respiratory obstruction in patients w/lung disease
- Vivid dreams, nightmares, fatigue, and cold extremities
Metaprolol
Beta 1 selective antagonist
- tx acute MI, cardiac congestion
- less effect on asthmatic patients
Atenolol
Beta 1 selective antagonist
- do not pass BBB
- manage hypertension
Timolol
Non selective beta blocker
- tx glaucoma ( Dec production of aqueous humor)
- topical effect
Pindolol
Beta antagonist and partial agonist
Nevibolol
Highly selective beta 1
- increase vasodilation -> effect endothelium to produce increase NO
Nadolol
Non selective beta blocker
Longer duration of action
Tx glaucoma
Mixed alpha1 and beta antagonist
Labetalol
Carvedolol
Dopamine receptor action and gprotein
D1 is Gs- vasodilation
D2 is Gi- emesis, inhibition of prolactin
Dopamine agonist
Fenoldopam- tx hypertension, heart failure, and MI, diuretic.
Tx for Parkinson’s disease
D2 agonist:
Levadopa
Apmorphine
Bromocriptine
Metoclorprimidine and domperidone
D2 antagonist
- increase peristalsis
- increase gastric emptying
- constrict sphincter -tx GERD
- block D2 receptor in CTZ of medulla- antinuasea and antiemetic action
Tx orthostatic hypotension
- Milodrine (alpha 1 agonist)
2. Yohimbine (alpha 2 antagonist)
