Pharmacology - Cardiac Function

Furosemide is a loop diuretic that acts on the ascending limb of the loop of Henle in the kidneys. It inhibits the reabsorption of sodium and chloride ions, leading to increased urine production. Thiazides, on the other hand, are a class of diuretics that act on the distal convoluted tubule in the kidneys. They inhibit the reabsorption of sodium, chloride, and water, resulting in increased urine production. Furosemide is considered more potent because it has a stronger and more rapid diuretic effect compared to thiazides.

Amiodarone is a medication that acts as a potassium (K+) channel blocker. This means that it inhibits the flow of potassium ions through channels in the cell membrane, leading to a decrease in the action potential (AP) duration. By blocking these channels, amiodarone helps to regulate the electrical activity of the heart, making it useful in the treatment of certain cardiac arrhythmias. Although it has some antihypertensive effects, its primary mechanism of action is related to its ability to block potassium channels.

Thiazides are a type of diuretic medication that increase the transport of sodium chloride in the distal convoluted tubule of the kidneys. This leads to increased urine production and helps to reduce fluid retention in the body. Thiazides are commonly used in patients with mild heart failure and edema, as they help to alleviate symptoms by promoting fluid excretion. They are not typically used for angina pectoris, which is a condition characterized by chest pain due to reduced blood flow to the heart.

Lidocaine is a medication that acts as a sodium (Na+) channel blocker, meaning it inhibits the flow of sodium ions through the channels in the cell membranes. This blockade leads to a decrease in the excitability of cells, including cardiac cells, which can help to prevent abnormal electrical activity and arrhythmias. Therefore, lidocaine is considered a good antiarrhythmic medication.

Clonidine is a medication that is classified as an antihypertensive and an alpha 2 agonist. As an antihypertensive, it is used to treat high blood pressure. As an alpha 2 agonist, it works by stimulating alpha 2 receptors in the brain, leading to a decrease in the release of norepinephrine (NE). This decrease in NE results in a decrease in heart rate (HR) and blood pressure (BP). Therefore, the correct answer is "Antihypertensive, alpha 2 agonist."

Not an ACE inhibitor, but an AT1 receptor blocker (ARB)

Loop diuretics are a class of medications that work by inhibiting an ion cotransporter in the loop of Henle, a part of the kidney tubules. This inhibition leads to decreased reabsorption of water, resulting in increased urine production and decreased fluid volume in the body. Loop diuretics are commonly used to treat conditions such as pulmonary edema and severe hypertension, where there is a need to reduce fluid overload. In some cases, loop diuretics may be prescribed in combination with a sympatholytic (a medication that blocks the effects of the sympathetic nervous system) and a vasodilator (a medication that widens blood vessels) to further manage hypertension.

decreased Ca2+ moving into muscle causes vasodialtion
Decreased Ca2+ into heart muscle decreases HR

Nitroglycerin causes increased cGMP, which in turn causes vasodilation. This means that it relaxes and widens the blood vessels, allowing for increased blood flow. This effect makes nitroglycerin useful in treating conditions such as angina, where there is a decrease in blood flow to the heart. However, it should not be administered with sildenafil, as both medications can cause a significant drop in blood pressure when taken together.

Digoxin inhibits Na+/K+ ATPase, which is responsible for pumping sodium out of the cell and potassium into the cell. By inhibiting this pump, digoxin increases the concentration of sodium inside the cell. This increase in intracellular sodium leads to a decrease in intracellular calcium levels. Digoxin also causes a decrease in sympathetic nervous system (SNS) activity, which reduces the SNS baroreceptor response. This means that the blood vessels won't dilate to compensate for the increased heart rate caused by digoxin. Quinidine helps clear digoxin faster from the body to prevent toxicity.

Good in heart failure b/c it causes decreased blood fluid because ACE isnt converting AI to AII -> which decreases the pressure the heart is working against
Do not use in patients with edema

INCREASE cGMP causes relaxation

Sildenafil, commonly known as Viagra, is a medication that inhibits the enzyme phosphodiesterase. By inhibiting this enzyme, sildenafil causes an increase in cyclic guanosine monophosphate (cGMP), which leads to the relaxation and dilation of blood vessels, including those in the smooth muscle. However, when sildenafil is mixed with nitrites, it can cause tachycardia, an abnormally fast heart rate.

Prazosin is an alpha 1 blocker, which means it blocks the alpha 1 receptors in the smooth muscles of blood vessels, causing vasoconstriction. This leads to an increase in blood pressure. The baroreceptors detect the increase in blood pressure and signal the heart to decrease its rate, resulting in a decrease in heart rate. Prazosin also increases renin release, which in turn increases blood volume. To manage the potential side effects of prazosin, it is often administered in combination with a beta-blocker or a diuretic to help control blood pressure and fluid balance.

Metroprolol is a non-selective beta blocker that works by decreasing heart rate (HR), which in turn lowers blood pressure (BP). It also decreases renin release from the kidney, helping to decrease blood volume and further lower BP. The decrease in HR also leads to a decrease in myocardial oxygen requirement, making it useful in the treatment of angina pectoris. Additionally, metroprolol has antiarrhythmic and antihypertensive properties.

Angiotensin II is a molecule that binds to both AT1 and AT2 receptors. When it binds to AT1 receptors, it causes an increase in the release of norepinephrine (NE) presynaptically. This leads to an increase in sympathetic activity. Additionally, the binding of Angiotensin II to AT1 receptors on smooth muscle causes a decrease in calcium levels, resulting in vasodilation. Angiotensin II also stimulates the release of aldosterone and antidiuretic hormone (ADH), which increase blood volume. Overall, Angiotensin II's binding to AT1 and AT2 receptors and its effects on NE release and blood volume contribute to its role as a vasoconstrictor.

Minoxidil is an antihypertensive medication that works by opening K+ channels, leading to hyperpolarization. This hyperpolarization causes vasodilation, which helps to lower blood pressure. Additionally, when blood pressure drops, the baroreceptors in the body detect this change and try to increase heart rate in order to compensate. Therefore, minoxidil not only causes vasodilation but also triggers a reflex response to increase heart rate.