adrenergic antagonist Flashcards
how do adrenergic antagonist act?
by binding reversibly or irreversibly to the receptor without triggering any response, and preventing any endo or exo agonist from binding.
what are the primary diseases that are treated by adrenergic antagonist
mainly cardiovascular diseases but also work on some cns diseases
how can alpha 1 blockers effect the BP?
due to the reduction of the sympathetic tone of blood vessels therefore decreasing peripheral resistance
Selective α2-adrenergic blockers have limited
clinical utility
okii
answer the following about Phenoxybenzamine
is it selective or non selective to what receptor?
what are the effects on the:
1. CVS
2.epinephrine reversal
is it used for hypertension
what are the therapeutic uses
what are the adverse effects
1.nonselective and noncompetitive alpha 1 and 2 blocker
- a) lowers peripheral blood vessels vassoconstriction
blocks the alpha 2 presynaptic receptors which leads to tachycardia by increasing norepinephrine and increasing contractility and cardiac output
b) it blocks the effects of epinephrine for example vassoconstriction but doesnt effect the isoproterenol effect on beta receptors
- it was unsuccessful in maintaining lowered Bp and no longer used
4.used for pheochromocytoma (sweating and hypertension) ,for frostbites and raynaud disease
- postural hypotension,nasal stuffiness, nausea, vomiting/ reflex tachycardia
answer the following about Phentolamine
how does it differ from Phenoxybenzamine
for how long does it last
what are the effects
what are the uses
is it useful for hypertensive crisis?
- its is, unlike phenoxybenzamine, competitive
- for 4 hours after an injection
- similar to phenoxybenzamine
- short term management of pheochromocytoma
preventing dermal necrosis after extravasation of norepinephrine - yes, they happen due to 1.abrupt withdrawal of clonidine
- ingesting tyramine-coated foods in patients taking MAOIs
answer the following about Prazosin, terazosin, and doxazosin
are they selective or non selective
what are the uses
what is the duration of doxazosin
whats the action on BP
what are the therapeutic uses
what are the adverse effects
1.selective, competitive blockers of alpha 1
- hypertension
- long duration of action
4.relaxes both the arterial and venous smooth muscles and lowers the peripheral vascular resistance.
no changes on the CO and renal blood flow
5.used for individuals with elevated BP, the first dose might cause a hypotensive response and cause fainting so we lower it to the 1/3 or 1/4 and taking it before bed time
6.▪dizziness, a lack of energy, nasal congestion, headache,drowsiness
▪orthostatic hypotension.
▪Male sexual function is affected
.floppy iris syndrome
.An additive antihypertensive effect occurs when α1 antagonists are given with vasodilators such as nitrates or PDE-5 inhibitors (for example, sildenafil), thereby necessitating cautious dose titration and use at the lowest possible doses
what are the differences between Tamsulosin & alfuzosin & silodosin and Prazosin, terazosin, doxazosin
- Tamsulosin & alfuzosin & silodosin are also selective alpha 1 antagonist but they are used benign prostatic hyperplasia (more selective to alpha1 a)
- they are less pronounce when it comes to BP effect because they are less selective to alpha1 b
alpha 1 a are found on the bladder and prostate
answer the following about Yohimbine
selective to what?
where is it found?
on what level does it work to increase sympathetic outflow to the periphery
used for what?
1.selective and competitive for alpha 2
2.found as a component of the bark of yohmbie tree
- cns level
- used as a sexual stimulant to treat erectile dysfunction but not recommended due to the lack of demonstrated efficacy
answer the following about beta blockers
are they competitive?
are they selective?
what do they differ in?
used in what?
what suffix do we use for them?
- yes
- can be both, but when we say beta blockers we mean Beta1
- • intrinsic sympathomimetic activity,
• CNS effects,
• blockade of sympathetic receptors,
• vasodilation
• pharmacokinetics
4.systemic as well as portal hypertension, angina, cardiac arrhythmias, myocardial infarction, heart failure, hyperthyroidism, and glaucoma.
- olol
note: there is no clinically useful beta 2 blockers
answer the following about propranolol
is it selective
what are the actions
what are the uses
what are the pharmacokinetics
what are the side effects
what are the drug interactions
- non-selective, effects both beta 1 and 2
2.decreses the HR and CO
lowers the SA and AV node activity
lowers the cardiac work and oxygen consumption
increases peripheral vascular resistance by blocking beta 2—- no vasodilation. and because it decreases CO it triggers a reflex peripheral vasoconstriction
in patients with hypertension the total peripheral resistance returns to normal due to down regulation of receptors with a decrease in systolic and diastolic BP
causes bronchoconstriction there for it should not be given to COPD and asthma patients (only the non selective ones)
it decreases glycogenolysis and glucagon secretion—–causes hypoglycemia in patients with diabetes
3.hypertension by lowering CO,inhibiton of renin release and decrease in peripheral resistance and sympathetic outflow to the cns
angina by decreasing the oxygen requirement and used for chronic management of stable angina
MI by reducing the size and early mortality, reduce the oxygen demand, and reduce the incidence of sudden arrhythmic death
migraine when used prophylactically
hyperthyroidism by blunting the widespread sympathetic stimulation
4.highly lipopholic, goes through first pass and only 25% reaches, can cross the BBB with 4L/kg Vd, excreted by urine
5.bronchoconstriction
arrhythmia and should be tapered off gradually for a few weeks due to the upregulation of the receptors
sexual impairment
metabolic disturbance like hypoglycemia and increase in LDL, triglyceride and reduced HDL
CNS effects:
• Depression, dizziness,
• lethargy, fatigue,
• weakness,
• visual disturbances,
• hallucinations,
• short-term memory loss,
• emotional lability,
• and vivid dreams
6.Drug interactions:
Drugs that inhibit the metabolism of propranolol, such as cimetidine, fluoxetine, paroxetine, and ritonavir, may
potentiate its antihypertensive effects.
Conversely, those that stimulate or induce its metabolism,such as barbiturates, phenytoin, and rifampin, can decrease its effects.
answer the following about Timolol and Nadolol
are they selective
what are the uses of timolol
how do they treat glaucoma
- nonselective but more potent than propranolol
- for open angle glaucoma by reducing the production of aqueous humor
3.by reducing the production of aqueous humor, When administered to the eye, the onset is about 30 minutes,
and the effects last for 12 to 24 hours.used for chronic management and not acute attacks
answer the following about Acebutolol, atenolol, metoprolol, bisoprolol, betaxolol, nebivolol,& esmolol
are they selective
what are the actions
what makes esmolol and nebivolol special
what are the uses
- more selective to Beta 1 specially acebutolol, atenolol, and metoprolol
- lower BP ans increases the tolerance in angina
- ▪Esmolol has a very short t1/2 due to metabolism. used to control blood pressure or heart rhythm in critically ill patients and those undergoing surgery or diagnostic procedures
▪Nebivolol also release nitric oxide and causes
vasodilation
- The cardioselective β-blockers are useful in hypertensive patients with impaired pulmonary function.
•First line therapy for chronic stable angina.
•Bisoprolol and metoprolol are indicated for management of chronic heart failure
•coldness of extremities, a common side effect of β-blocker therapy, is less frequent .
note ▪These drugs have relatively little effect on pulmonary function, peripheral resistance, and carbohydrate metabolism
answer the following about Acebutolol and pindolol:
which one is selective
what makes them special
what is the use
- acebutolol is beta one selective
- they are partial agonists
- used for hypertensive patients with moderate bradycardia.
answer the following about Labetalol and carvedilol:
what makes them special
what are the uses
what are the side effects
- they are nonselective β-blockers with concurrent α1-blocking actions that produce peripheral vasodilation, thereby reducing blood pressure.
2.Useful in treating hypertensive patients for whom increased peripheral vascular resistance is undesirable.
Carvedilol also decreases lipid peroxidation and vascular wall thickening which is good in heart failure
Labetalol is used as an alternative to methyldopa in the treatment of pregnancy-induced hypertension.
Intravenous labetalol is also used to treat hypertensive emergencies
3.Orthostatic hypotension and dizziness are associated with α1blockade.
note
• β blockers should not be given in acute HF.
• However, carvedilol, metoprolol and bisoprolol are beneficial inpatients with stable chronic HF.
