Exam Revision - Pharm Drugs

Noradrenaline is a type of drug known as an adrenoceptor agonist. This means that it activates adrenoceptors, which are receptors found on the surface of cells that respond to adrenaline and noradrenaline. By activating these receptors, noradrenaline can increase heart rate, constrict blood vessels, and raise blood pressure. This makes it useful in medical conditions such as low blood pressure or shock.

Adrenaline is classified as an adrenoceptor agonist. This means that it binds to and activates adrenoceptors, specifically the alpha and beta adrenoceptors. Adrenaline, also known as epinephrine, is a hormone and neurotransmitter that plays a crucial role in the fight-or-flight response. It increases heart rate, dilates airways, and constricts blood vessels, among other effects. By activating adrenoceptors, adrenaline produces these physiological responses, making it an adrenoceptor agonist.

Noradrenaline is a neurotransmitter that acts on both alpha and beta adrenoceptors. However, it has a higher affinity for alpha receptors, making it more preferential towards them. This means that noradrenaline will primarily bind to alpha receptors, but it can also bind to beta receptors to a lesser extent.

Atenolol is classified as an adrenoceptor antagonist. Adrenoceptor antagonists, also known as beta blockers, work by blocking the action of adrenaline on beta receptors in the body. This leads to a decrease in heart rate and blood pressure, making them commonly used in the treatment of conditions such as hypertension, angina, and arrhythmias. Atenolol specifically targets beta-1 adrenoceptors, which are primarily found in the heart. By blocking these receptors, atenolol helps to reduce the workload on the heart and improve its efficiency.

Salbutamol acts upon beta 2 adrenoceptors. Beta 2 adrenoceptors are a type of receptor found in the smooth muscles of the airways. Activation of these receptors by Salbutamol causes relaxation of the airway smooth muscles, leading to bronchodilation. This makes Salbutamol an effective medication for treating conditions such as asthma and chronic obstructive pulmonary disease (COPD).

Phenoxybenzamine is classified as an adrenoceptor antagonist. Adrenoceptor antagonists, also known as alpha blockers, block the action of adrenaline and noradrenaline on alpha receptors in the body. This leads to relaxation of smooth muscles in blood vessels, resulting in vasodilation and decreased blood pressure. Phenoxybenzamine specifically blocks alpha-1 receptors, which are found in blood vessels, prostate gland, and bladder neck. It is commonly used to treat conditions such as hypertension, benign prostatic hyperplasia, and pheochromocytoma.

Pilocarpine is classified as a muscarinic antagonist. This means that it blocks the activity of muscarinic receptors, which are found in various tissues in the body. By blocking these receptors, pilocarpine inhibits the effects of acetylcholine, a neurotransmitter that normally activates these receptors. This leads to various physiological effects, such as decreased heart rate, reduced salivation, and constriction of the pupils. Therefore, pilocarpine is commonly used in the treatment of conditions like glaucoma and dry mouth.

Pancuronium is a neuromuscular blocking agent that acts as a nicotinic antagonist. It blocks the nicotinic acetylcholine receptors in the neuromuscular junction, preventing the binding of acetylcholine and inhibiting muscle contractions. This results in muscle relaxation and paralysis, making it useful in surgeries and intubation procedures. It does not have any effect on muscarinic receptors or ACE inhibition, and it is not an adrenoceptor agonist.

Pancuronium is a neuromuscular blocking agent used in anesthesia. It is classified as a competitive, non-depolarizing agent. This means that it competes with acetylcholine for the receptors on the motor end plate of the muscle, preventing the transmission of nerve impulses and causing muscle relaxation. Unlike depolarizing agents, which cause initial muscle contractions before relaxation, pancuronium directly causes muscle relaxation without any initial contractions.

The acetylcholine receptor is propped open, allowing continued flow of potassium ions into the extracellular fluid

Acetylcholine is classified as a muscarinic agonist because it binds to and activates muscarinic receptors in the body. Muscarinic receptors are found in various tissues and organs, including the heart, smooth muscles, and glands. Activation of muscarinic receptors by acetylcholine leads to various physiological responses, such as decreased heart rate, increased glandular secretions, and contraction of smooth muscles. Therefore, acetylcholine acts as an agonist, mimicking the effects of the neurotransmitter acetylcholine on muscarinic receptors.

Tubocurarine is a neuromuscular blocking agent used during surgery to induce muscle relaxation. It acts by competitively blocking the nicotinic acetylcholine receptors at the neuromuscular junction, preventing the binding of acetylcholine and inhibiting muscle contraction. It is classified as a non-depolarizing agent because it does not cause depolarization of the muscle membrane. Therefore, the correct answer is "competitive, non-depolarizing."

Phentolamine is classified as an adrenoceptor antagonist. Adrenoceptor antagonists, also known as alpha-blockers, block the action of adrenaline on alpha-adrenergic receptors. Phentolamine specifically blocks alpha-1 adrenergic receptors, leading to relaxation of smooth muscles in blood vessels and other tissues. This results in vasodilation and a decrease in blood pressure.

Phentolamine is a medication that acts upon alpha adrenoceptors. Alpha adrenoceptors are a type of receptor found in various tissues, including blood vessels, where they regulate constriction of the smooth muscles. Phentolamine works by blocking these receptors, leading to relaxation of the smooth muscles and dilation of the blood vessels. This can be useful in conditions such as high blood pressure or certain types of erectile dysfunction.

Atropine is classified as a competitive muscarinic antagonist. This means that it competes with acetylcholine for binding to the muscarinic receptors in the body, blocking their activation. By doing so, atropine inhibits the effects of acetylcholine on these receptors, resulting in a variety of physiological effects such as increased heart rate, dilation of the pupils, and decreased secretions.

Suxamethonium is classified as a nicotinic antagonist. This means that it blocks the action of acetylcholine at nicotinic receptors, preventing the transmission of nerve signals. As a result, it causes muscle relaxation and is commonly used as a muscle relaxant during surgery or intubation. It is important to note that Suxamethonium does not have any effect on muscarinic receptors, adrenoceptors, or ACE inhibitors.

Adrenaline is a hormone that acts on both alpha and beta adrenoceptors. The statement that at low doses, adrenaline acts more on beta receptors than alpha receptors, and vice versa at high doses, is true. Adrenaline has a higher affinity for beta receptors, and at low doses, it predominantly binds to beta receptors, resulting in effects such as increased heart rate and bronchodilation. At high doses, adrenaline binds to both alpha and beta receptors, leading to vasoconstriction and increased blood pressure.

Isoprenaline is classified as an adrenoceptor agonist. This means that it activates adrenoceptors, which are receptors for adrenaline and noradrenaline. As an adrenoceptor agonist, Isoprenaline mimics the effects of adrenaline and noradrenaline in the body, leading to increased heart rate, bronchodilation, and increased blood flow to certain organs.

Salbutamol is an adrenoceptor agonist. This means that it acts on the adrenergic receptors in the body, specifically targeting the beta-2 adrenergic receptors. By stimulating these receptors, Salbutamol causes relaxation of the smooth muscles in the airways, leading to bronchodilation. This makes it an effective medication for treating conditions such as asthma and chronic obstructive pulmonary disease (COPD). Salbutamol does not have any effect on nicotinic or muscarinic receptors, and it is not primarily a vasodilator.

Phenoxybenzamine is an irreversible alpha-adrenergic antagonist. This means that once it binds to the alpha-adrenergic receptors, it forms a covalent bond and cannot be easily displaced. This results in a long-lasting and irreversible blockade of the receptors. Therefore, the correct answer is "Irreversible."

Tubocurarine is a neuromuscular blocking agent that acts as a competitive antagonist at the nicotinic acetylcholine receptors in the neuromuscular junction. It prevents the binding of acetylcholine to the receptors, leading to muscle relaxation and paralysis. Therefore, the correct answer is "nicotinic antagonist."