NE Agonists and Blockers

Neuroreceptors that bind to norepinephrine (NE) and epinephrine, triggering various physiological responses.

Cause vasoconstriction, increased blood pressure, and mydriasis (pupil dilation).

Inhibit NE release and insulin release.

Cause tachycardia (increased heart rate), increased lipolysis, and increased myocardial contractility.

Cause vasodilation, bronchodilation, and relaxation of uterine smooth muscle.

Drugs that directly bind and activate adrenergic receptors.

Drugs that cause the release of norepinephrine (NE).

Drugs that directly activate adrenergic receptors and cause the release of NE.

Drugs that activate adrenoceptors, mimicking the effects of norepinephrine (NE) and epinephrine (EP).

Stimulation causes relaxation of smooth muscles in the lungs, uterus, and blood vessels.

Located in the kidneys and other areas; cause dilation of blood vessels and decreased blood pressure.

Drugs that mimic the actions of norepinephrine (NE) and epinephrine (EP).

Drugs that release norepinephrine (NE) from nerve terminals, having widespread, nonspecific effects.

Drugs that mimic the effects of the sympathetic nervous system (SNS) by activating adrenergic receptors.

Adenylate cyclase converts ATP to cAMP, which activates kinases, leading to phosphorylation and ultimately muscle contraction.

Alpha receptors are primarily involved in vasoconstriction and other responses while Beta receptors are involved in bronchodilation, increased heart rate and other responses.

Examples include epinephrine, norepinephrine, dopamine, phenylephrine, albuterol, and many others.

Alpha 1 agonists primarily cause vasoconstriction, leading to increased blood pressure and potential for nasal decongestion.

A classic alpha 1 agonist used for nasal decongestion, it directly activates alpha 1 receptors causing vasoconstriction in the nasal passages.

This drug is a potent beta 1 and beta 2 agonist, widely used in emergency situations due to its strong effect on the heart and lungs.

Beta 2 agonists are the primary treatment for acute asthmatic bronchoconstriction. Their action relaxes airway smooth muscle, opening up the airways.

A commonly used beta 2 agonist, it relieves bronchoconstriction and improves breathing in asthma patients by selectively activating beta 2 receptors.

Epinephrine is the drug of choice to treat anaphylactic shock, a severe allergic reaction. It acts by stimulating both alpha and beta receptors to counteract the life-threatening symptoms.

This alpha 2 agonist acts in the central nervous system (CNS) to lower blood pressure by reducing the release of norepinephrine.

A direct-acting alpha 1 agonist that increases blood pressure by constricting blood vessels.

Drugs that stimulate adrenergic receptors in the central nervous system (CNS), often used for weight loss, attention deficit disorder, narcolepsy, and sometimes abused for mood-altering effects.

Drugs that stimulate adrenergic receptors in the eye, used to reduce conjunctival itching caused by allergies (phenylephrine) and treat glaucoma (epinephrine).

Drugs that stimulate adrenergic receptors in the genitourinary tract, primarily beta 2 agonists used to suppress premature labor (ritodrine, terbutaline) and alpha agonists (like ephedrine) to improve urinary continence.

Drugs that mimic the sympathetic nervous system, affecting blood vessels (alpha for constriction, beta 2 for relaxation), heart (beta 1 for increased heart rate and contractility), and blood pressure (alpha raises, beta lowers).

Drugs that mimic the sympathetic nervous system, affecting the eye by increasing aqueous humor outflow (alpha) and decreasing its production (beta), influencing eye pressure.

Drugs that mimic the sympathetic nervous system, affecting the respiratory system primarily through beta 2 receptors, causing relaxation of bronchial smooth muscle, leading to bronchodilation.

Drugs that mimic the sympathetic nervous system, affecting the gastrointestinal (GI) tract by relaxing smooth muscles (beta) and decreasing acetylcholine release (alpha 2), affecting digestion and motility.

Drugs that mimic the sympathetic nervous system, affecting various systems including the uterus (beta for relaxation, alpha for contraction), exocrine glands (controlling secretions), and fat cells (increasing lipolysis).

A potent vasoconstrictor and cardiac stimulant that increases blood pressure.

Similar effects to epinephrine, but slightly less potent.

A strong beta agonist, primarily affecting beta receptors. Dilates blood vessels.

Direct-acting drugs like phenylephrine or methoxamine increase blood pressure by constricting blood vessels.

Epinephrine (EP) is used to counter the effects of anaphylaxis by reversing low blood pressure, bronchospasm, and congestion.

These drugs can lead to hypertension, increased risk of heart problems, and cardiac failure.

Only drugs like cocaine and amphetamine can cross the blood-brain barrier easily, leading to central nervous system side effects.

Drugs that block alpha receptors, primarily found on vascular smooth muscle, leading to a decrease in blood pressure.

Non-selective alpha antagonist that blocks both alpha 1 and alpha 2 receptors, used to lower blood pressure and treat pheochromocytoma.

A phenomenon where activating alpha and beta receptors in the same tissue leads to opposing effects on blood pressure. For example, epinephrine increases blood pressure by activating both alpha and beta receptors, but a selective alpha 1 antagonist blocks both alpha and beta actions of epinephrine, resulting in lowered blood pressure.

A tumor of the sympathetic nervous system that produces excessive norepinephrine and epinephrine, leading to hypertensive crisis.

Drugs that activate alpha 2 receptors, ultimately reducing sympathetic outflow from the brain and norepinephrine release from neurons, lowering blood pressure.

An alpha 2 agonist used to treat hypertension by reducing sympathetic activity.

Drugs that reduce sympathetic activity, generally by blocking adrenergic receptors.

Drugs that specifically block alpha 1 receptors, leading to vasodilation and lower blood pressure.

Drugs that block the effects of the sympathetic nervous system by antagonizing adrenergic receptors. They can be selective for specific receptor subtypes or non-selective, affecting multiple receptors.

A tumor of the adrenal medulla that releases excessive amounts of catecholamines (epinephrine and norepinephrine), causing high blood pressure, sweating, palpitations, and headaches.

These drugs are primarily used for treating Pheochromocytoma, a rare tumor. They are not selective and block both alpha 1 and alpha 2 receptors.

These drugs are used for treating hypertension and benign prostatic hyperplasia (BPH). They specifically block alpha 1 receptors, which are linked to vasoconstriction and prostate function.

These drugs are used for treating various conditions, including hypertension, ischemic heart disease, and neurological disorders. They block beta receptors, affecting heart rate, blood pressure, and other bodily functions.

Reversible alpha antagonists have a duration of action tied to their half-life, while irreversible alpha antagonists form a strong bond with the receptor and their effects last for days. They require new receptor synthesis to restore function.

Phenoxybenzamine is an irreversible alpha blocker used pre-operatively to control the high blood pressure and other symptoms caused by the tumor's catecholamine release.

Phentolamine is a reversible alpha blocker that is used to treat hypertensive episodes associated with Pheochromocytoma. It can also be administered intravenously to reverse the effects of alpha agonists.

A tumor most often found in the adrenal gland that releases excessive amounts of norepinephrine and epinephrine, causing high blood pressure, sweating, palpitations, and headaches.

A condition characterized by high blood pressure, sweating, palpitations, and headaches due to excessive release of norepinephrine and epinephrine from a tumor in the adrenal gland.

Alpha blockers cause vasodilation, leading to a decrease in blood pressure. This effect is more pronounced when standing due to the increased need for norepinephrine to maintain blood pressure.

Alpha blockers can cause postural hypotension (low blood pressure upon standing) and reflex tachycardia (increased heart rate as a response to lowered blood pressure).

An irreversible alpha blocker with a long duration of action (14-48+ hours), used to treat pheochromocytoma and other conditions.

A selective alpha 1 blocker with a relatively low incidence of tachycardia, used to treat hypertension and benign prostatic hyperplasia (BPH).

A reversible alpha 1 antagonist with a long half-life, used to treat hypertension and benign prostatic hyperplasia (BPH).

A long-acting alpha 1 blocker with a half-life of 22 hours, used to treat hypertension and benign prostatic hyperplasia (BPH).

Beta blockers decrease blood pressure by reducing heart rate, constricting blood vessels, and inhibiting the renin-angiotensin system.

Beta blockers can cause airway constriction by blocking the beta 2 receptors. Selective beta 1 blockers have less effect on the lungs.

Beta blockers increase pressure in the eye, potentially leading to glaucoma. They are also used topically to treat glaucoma.

Beta blockers can inhibit lipolysis (fat breakdown) and reduce glycogenolysis in the liver. Caution is advised with diabetes patients.

Beta blockers are widely used to treat hypertension, ischemic heart disease, cardiac arrhythmias, and glaucoma.

Beta blockers, especially propranolol, are used to treat migraines and other neurological conditions.

The first beta blocker drug, non-selective, with numerous effects on the central nervous system.

A non-selective beta blocker used topically for the treatment of glaucoma.

Alpha blockers are used primarily to treat hypertension (high blood pressure) and pheochromocytoma (a tumor that releases excessive catecholamines).

Beta blockers are used to treat hypertension, angina (chest pain), heart failure, and other conditions associated with the cardiovascular system. They are also used to manage stage fright.

Non-selective beta blockers can worsen asthma due to their blocking of beta-2 receptors in the lungs, and they can exacerbate hypoglycemia in insulin-dependent patients.

Beta blockers, particularly non-selective and high lipid-soluble ones, can cause CNS side effects like sedation, sleep disturbance, and depression.

Reversible alpha blockers have a duration of action tied to their half-life, while irreversible alpha blockers form a strong bond with the receptor and their effects last for days. They require new receptor synthesis to restore function.

Drugs that block beta receptors, resulting in effects such as reduced heart rate, blood pressure control, and other physiological changes.

Beta blockers are widely used for conditions like hypertension, angina, heart failure, and even to manage stage fright.

Alpha blockers are primarily used to treat hypertension and pheochromocytoma, a tumor that releases excessive catecholamines.

Beta blockers decrease heart rate and blood pressure by blocking beta receptors in the heart.

Alpha blockers cause vasodilation (widening of blood vessels) leading to a decrease in blood pressure.

Common beta blockers include propranolol, atenolol, metoprolol, and timolol. Each has specific properties and uses.