Skip to content

Beta Adrenergic Blocker Drugs Lesson Part 2 | Beta Adrenergic Blocker Drugs Notes Part 2

  • by

Beta Adrenergic Blocker Drugs Lesson Part 2 | Beta Adrenergic Blocker Drugs Notes Part 2

One more important point regarding beta blockers is about their solubility some of the lipid insoluble beta blockers are nedololol sotalol adenolone acebutylol betaxalol viscoprolol and cell prolol they are excreted via kidney now well let’s talk about acetyl all which needs a special mention because of the fact that it has all the properties it is cardio

Selective it has got intrinsic sympathomimetic activity it has got membrane stabilizing effect and lastly it is lipid insoluble now something about pharmacological actions of beta blockers now the prototype drug is propanolol propanol is a prototype drug it has predominant actions on heart and blood vessels so when it is prescribed what it does is it decreases

Increase sympathetic activity on heart it decreases cardiac output it may initially increase peripheral vascular resistance due to blockade of beta2 receptors sinus rate goes down conduction in atria gets delayed whereas some beta blockers have membrane stabilizing effect and propanol is one of them this is useful as anti-arrhythmic action as anti-arrhythmic

Agent however this antiarrhythmic effect occurs at higher doses now heart rate which normally gets increased during exercise so exercise induced heart rate gets somewhat lowered and force of contraction of myocardium that also gets decreased secondly propanol all exerts some actions on blood vessels also so what it does catecholamines which normally cause

Vasoconstriction so propanol can somewhat control that and isoprenallene which induces fall in blood pressure that is blocked by propanology no doubt peripheral vascular resistance gets increased on short-term basis initially but upon long-term basis peripheral vascular resistance gets decreased and next important thing is propanol leads to decrease in oxygen

Demand so the balance between oxygen demand and supply is controlled and that is helpful in angina factors now blood pressure gets lowered in hypertensive individuals actions due to sympathetic or activity get reduced or controlled or they get somewhat blocked because ultimately they are antagonists and they are two competitive antagonists and pure antions

There is a central sympatholytic action as well that leads to inhibition of renin release due to beta-1 blockade this action is helpful as an anti-hypertensive now we can summarize the effects of this proponal all that is it can act as an antihypertensive it can act as an anti-anginal agent and it can act as an antiarrhythmic agent it has all the properties it

Is used in the treatment of hypertension it is used in the treatment of angina factories and it might have some antiarrhythmic effect because of the fact that it exerts membrane stabilizing effect now some actions of propanol on the respiratory system what is being observed is bronchoconstriction this bronchoconstrict is observed due to blockade of beta-2

Receptors which reside predominantly in bronchial smooth muscles now on the other hand this uh propanol all which is placed in the class non-selective beta blockers it has action or blockade on beta 1 receptors as well as beta 2 receptors beta-1 receptors are found in heart and beta-2 receptors as i told you are found in the bronchial tree or bronchial smooth

Muscles whereas beta blockers which are beta 1 selective they do not block beta 2 receptors at all so such beta 2 such beta 1 selective beta blockers are helpful in the treatment of asthmatics who suffer from hypertension there we have to prescribe beta blockers which are beta 1 selective we can’t effort to prescribe propanolol which is non-selective beta

Blocker now coming to metabolic effects the result is hyperglycemia because of blockade of beta-2 receptors in the liver normally they are responsible for mediating glycogenolysis thirdly it might lead to increase in the level of these lipids increasing hyperlipidemia because levels of ldl gets increased on the contrary the beneficial cholesterol hdl levels

Go down now action on i there is an increase in the outflow and reduced across tumor formation that is useful in decreasing the intraocular pressure especially in glucoma now in cns tremers may get blocked mass cell degranulation that is also being prevented cardio selective beta blockers do not show this type of effect now other actions like say in case of

Betaxolor levobutoxylol meteopranolol timolol they have a neuroprotective action on retina so timolol is in fact only beta blocker that is used in eye ailments especially glucoma extra in addition to that at present we have levobitocillol that is highly effective much more than that of timolol now coming to brief pharmacologic profile proponent lol when it

Is given orally it has a low oral biability it undergoes extensive for sparse metabolism now on the other hand we have metoprolol and levitolol they also undergo first pass metabolism now metabolism of propanolol or beta blockers that takes place in the liver in case of propanol oil for hydroxypropanolol is the active metabolite that is why we observe longer

Duration of action in case of propanol now excretion that is adopted by a hepatic root metaprolol levitolol they adopt hepatic root whereas ethanol nadolol they adopt renal root for excretion however the remaining beta blockers they may adopt both hepatic as well as renal roots for getting excreted now water soluble beta blockers get incompletely metabolized

For example we have ethanol cell prolol sotalol pindolol and plasma protein binding node out is high in case of beta blockers it is carbonyl that has around 98 percent plasma protein binding on the other hand we have cell prologue that has the lowest plasma protein binding just five percent now coming to clinical uses these can be grouped into two main classes

First of all we have cardiovascular uses and secondly we have non-cardiovascular uses among the cardiovascular uses they are prescribed in essential hypertension in the prophylaxis of angina in aridemias in myocardial infarction and cardiac failure coming to non-vascular uses these can be utilized in migraine they have anti-anxiety effect they can control

Essential tremors alcohol and opioid dependence they can control akathisia and they have some ophthalmic uses also in glaucoma etc but one thing is you have to be very cautious these can’t be withdrawn abruptly after chronic use it can be dangerous you

Transcribed from video
Beta Adrenergic Blocker Drugs Lesson Part 2 | Beta Adrenergic Blocker Drugs Notes Part 2 By Health Show