Pharmacology - Antihypertensives

Armando Hasudungan・2 minutes read

Blood flow through the body is regulated by the heart, organs, and arteries, with various medications like ACE inhibitors and diuretics used to manage hypertension and lower blood pressure, each with specific mechanisms of action and potential side effects. Multiple types of medications, including beta blockers, calcium channel blockers, and diuretics, target different aspects of the cardiovascular system to help manage blood pressure and prevent complications associated with hypertension.

Insights

  • The cardiovascular system circulates blood through arteries and veins, with cardiac output impacting blood pressure; organs like the liver, lungs, kidneys, and adrenal glands play crucial roles in regulating blood pressure, particularly focusing on arterial blood pressure.
  • Various classes of anti-hypertensive medications, such as ACE inhibitors, Angiotensin receptor blockers, Alpha 1 receptor blockers, beta blockers, calcium channel blockers, diuretics, and endothelin receptor antagonists, target different pathways to lower blood pressure, each with specific mechanisms of action and potential side effects.

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Recent questions

  • How does the body regulate blood pressure?

    The body regulates blood pressure through organs like the liver, lungs, kidneys, and adrenal glands, focusing on arterial blood pressure. Mean arterial pressure is calculated by cardiac output multiplied by total peripheral resistance, with systolic and diastolic blood pressure numbers indicating artery pressure during heart contraction and filling.

  • What are the consequences of untreated hypertension?

    Untreated hypertension, or high blood pressure, can have severe consequences. It can lead to heart disease, stroke, kidney damage, and other health issues. It is crucial to manage and treat hypertension to prevent these potential complications.

  • How do ACE inhibitors work to lower blood pressure?

    ACE inhibitors work by inhibiting Angiotensin converting enzyme, which reduces Angiotensin 2 levels and blood pressure. They are commonly used to treat hypertension and have side effects like dry cough. However, they may not be suitable for individuals with certain medical conditions.

  • What are the side effects of calcium channel blockers?

    Calcium channel blockers, which end in -dipine or -amil, block T-type and L-type calcium channels to reduce heart rate and smooth muscle contraction, lowering blood pressure. Common side effects include headache and dizziness, which may vary in intensity among individuals.

  • How do loop diuretics lower blood pressure?

    Loop diuretics target the ascending part of the nephron in the kidneys, inhibiting a specific transporter that reabsorbs sodium, chloride, and potassium back into circulation. By disrupting this process, loop diuretics prevent sodium from entering the blood vessel, leading to a decrease in blood pressure.

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Summary

00:00

Managing Blood Pressure: Medications and Mechanisms

  • Blood is pumped by the heart through arteries in red and returns via veins in blue, with cardiac output impacting blood pressure.
  • Organs like the liver, lungs, kidneys, and adrenal glands regulate blood pressure, focusing on arterial blood pressure.
  • Mean arterial pressure is calculated by cardiac output multiplied by total peripheral resistance (TPR), with systolic and diastolic blood pressure numbers indicating artery pressure during heart contraction and filling.
  • Hypertension, or high blood pressure, can have severe consequences if untreated, with anti-hypertensives like ACE inhibitors, Angiotensin receptor blockers, and Alpha 1 receptor blockers used for treatment.
  • ACE inhibitors inhibit Angiotensin converting enzyme, reducing Angiotensin 2 levels and blood pressure, with side effects like dry cough and contraindications for certain conditions.
  • Angiotensin receptor blockers block Angiotensin 2 receptors, lowering its activity and blood pressure, often used as an alternative to ACE inhibitors due to fewer side effects.
  • Alpha 1 receptor blockers target vessel epithelial cells, blocking noradrenaline's effect on smooth muscle cells to decrease blood pressure, with potential side effects like hypotension.
  • Beta blockers, ending in -ol, inhibit beta receptors to reduce sympathetic activity, affecting heart rate and contraction strength to lower blood pressure, with side effects like bradycardia and contraindications for lung and vascular diseases.
  • Calcium channel blockers, ending in -dipine or -amil, block T-type and L-type calcium channels to reduce heart rate and smooth muscle contraction, decreasing blood pressure, with side effects like headache and dizziness.
  • Diuretics work on the kidneys to induce diuresis, reducing fluid overload and blood pressure, with Loop, thiazide, and potassium-sparing diuretics as main types, each affecting urine output and fluid balance.

19:18

Diuretics and Antagonists: Blood Pressure Medications Explained

  • Loop diuretics target the ascending part of the nephron, inhibiting a specific transporter that reabsorbs sodium, chloride, and potassium back into circulation, disrupting this process prevents sodium from entering the blood vessel, leading to a decrease in blood pressure. Thiazide diuretics act on the distal part of the nephron, blocking a transporter that reabsorbs sodium and chloride, inhibiting this transporter reduces sodium and water reabsorption, lowering blood pressure. Potassium-sparing diuretics inhibit a transporter that reabsorbs sodium while secreting potassium, preventing sodium and water reabsorption, ultimately decreasing blood pressure and sparing potassium.
  • Side effects of loop and thiazide diuretics include electrolyte imbalances, hypotension, hyperuricemia, hyperglycemia, and metabolic alkalosis. In contrast, potassium-sparing diuretics can lead to hyperkalemia, metabolic acidosis, and gynecomastia. Endothelin receptor antagonists relax blood vessels by inhibiting endothelin receptors, causing vasodilation and lowering blood pressure, with side effects like headache, peripheral edema, and hypotension.
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