Pharmacology: Lipid- Lowering Drugs, Animation

00:05:31
https://www.youtube.com/watch?v=-VwH33qYjPw

Résumé

TLDRLipid-lowering drugs are designed to manage high cholesterol and triglyceride levels, thereby reducing the risk of cardiovascular events like heart attacks. The primary lipoproteins involved are chylomicrons, VLDL, LDL, and HDL — with HDL being beneficial for cardiovascular health. The drugs function through various mechanisms, such as inhibiting cholesterol synthesis or absorption, and promoting lipoprotein degradation. Statins, for instance, are prevalent due to their role in inhibiting HMG-CoA reductase, decreasing cholesterol production. Additionally, bile-binding resins increase cholesterol removal, ezetimibe and fibrates modulate absorption and metabolism, and PCSK9 inhibitors enhance LDL receptor activity. Common treatments often have side effects ranging from mild discomfort to more serious health implications. Proper timing and administration, like taking statins at night, optimize their effectiveness and mitigate adverse effects.

A retenir

  • 🩺 Lipid-lowering drugs aim to prevent heart disease by managing cholesterol levels.
  • 🦠 HDL is beneficial for blood vessel health, unlike other lipoproteins.
  • 💊 Statins inhibit cholesterol synthesis by targeting HMG-CoA reductase.
  • 🕒 Statins are best taken at night due to the body's natural cholesterol production cycle.
  • 🌿 Bile resins reduce cholesterol by increasing bile excretion and synthesis.
  • 🧬 Fibrates activate PPAR-alpha, affecting lipoprotein metabolism to boost HDL.
  • ⚖️ PCSK9 inhibitors enhance LDL receptor numbers, lowering LDL levels.
  • 🍽️ Ezetimibe restricts cholesterol absorption in the small intestine.
  • 🥛 Common side effects of resins include gastrointestinal issues like nausea and bloating.
  • 💡 Niacin effectively raises HDL but may have severe side effects if not tolerated well.

Chronologie

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    Lipid-lowering drugs prevent cardiovascular events by reducing cholesterol and triglycerides, which are transported in lipoproteins. They differ in content and function. HDL removes excess cholesterol, while others like LDL, VLDL, and chylomicrons are targeted for reduction. Statins, a first-line therapy, inhibit HMG-CoA reductase, reducing LDL but may cause muscle pain, diabetes, and liver damage. Bile reuptake inhibitors increase bile excretion, thus reducing cholesterol. Ezetimibe inhibits cholesterol absorption. Fibrates activate PPAR-alpha affecting triglyceride and HDL levels. PCSK9 inhibitors increase LDL uptake by inhibiting PCSK9. Niacin impacts lipid levels through various mechanisms but may have severe side effects.

Carte mentale

Vidéo Q&R

  • What are lipid-lowering drugs used for?

    They treat elevated cholesterol and triglyceride levels to prevent cardiovascular events.

  • What are the four major lipoprotein particles?

    The four major lipoproteins are chylomicrons, VLDL, LDL, and HDL.

  • How do statins work?

    Statins are competitive inhibitors of HMG-CoA reductase, reducing cholesterol synthesis and lowering plasma LDL levels.

  • What are some side effects of statins?

    Common side effects include muscle pain, muscle injury, potential development of diabetes, and liver damage.

  • How do bile-binding resins reduce cholesterol?

    They prevent bile acid reabsorption, prompting more cholesterol to be used for new bile synthesis, thus lowering blood cholesterol.

  • What is the role of PCSK9 inhibitors?

    They are monoclonal antibodies that inhibit PCSK9, increasing LDL receptors and reducing blood LDL levels.

  • What does Ezetimibe do?

    Ezetimibe inhibits dietary and biliary cholesterol absorption from the small intestine.

  • How do fibrates affect lipid levels?

    They activate PPAR-alpha, promoting degradation of triglycerides and increasing HDL levels.

  • What effect does Niacin have on lipid levels?

    Niacin lowers VLDL, LDL, and triglyceride levels while raising HDL.

  • How should statins be taken?

    Statins should be taken before bedtime since cholesterol synthesis usually occurs during fasting at night.

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Sous-titres
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Défilement automatique:
  • 00:00:03
    Lipid-lowering drugs are used to treat elevated levels of circulating cholesterol and triglycerides,
  • 00:00:09
    with the goal of preventing cardiovascular events such as heart attack or stroke.
  • 00:00:14
    These lipids can come from diet, from stores in adipose tissue, or can be synthesized endogenously.
  • 00:00:21
    Cholesterol and triglycerides are transported in blood plasma within large particles known
  • 00:00:25
    as lipoproteins, composed of lipids and proteins.
  • 00:00:29
    There are four major lipoprotein particles: chylomicrons, very low-density lipoprotein
  • 00:00:36
    (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL).
  • 00:00:44
    They differ in lipid content, hence density, and have different sets of proteins, and different
  • 00:00:49
    functions.
  • 00:00:51
    HDL acts to remove excess cholesterol from the circulation to the liver, and is therefore
  • 00:00:56
    beneficial for blood vessel health, unlike the other 3.
  • 00:01:00
    The liver secretes cholesterol in bile, part of which is eliminated from the body in feces;
  • 00:01:06
    the rest is recycled back to the liver.
  • 00:01:09
    Lipid-lowering therapy aims to reduce the circulating levels of chylomicrons, VLDL,
  • 00:01:15
    and LDL, but increase the level of HDL.
  • 00:01:20
    Mechanisms of existing drugs include: inhibition of cholesterol or lipoprotein production;
  • 00:01:26
    inhibition of intestinal cholesterol absorption; inhibition of bile reabsorption to promote
  • 00:01:31
    cholesterol removal; and promotion of lipoprotein degradation.
  • 00:01:36
    Statins are typically the first-line therapy, they inhibit endogenous production of cholesterol.
  • 00:01:42
    Statins are competitive inhibitors of HMG-CoA reductase - the enzyme that controls the rate-limiting
  • 00:01:48
    step in cholesterol synthesis.
  • 00:01:51
    As intracellular cholesterol decreases, the cells import more cholesterol from blood plasma
  • 00:01:56
    to fulfill their needs, effectively lowering plasma LDL levels.
  • 00:02:01
    Statins are best taken before bedtime, because cholesterol synthesis typically occurs during
  • 00:02:07
    fasting at night.
  • 00:02:09
    Common side effects include muscle pain and muscle injury which may increase with vigorous
  • 00:02:14
    exercise.
  • 00:02:16
    Other adverse effects include new development of diabetes and liver damage.
  • 00:02:21
    Another class of drugs are inhibitors of bile reuptake.
  • 00:02:25
    Normally, about 95% of bile acids delivered to the duodenum are reabsorbed back into the
  • 00:02:32
    blood.
  • 00:02:33
    The 5% that is excreted in feces is compensated for by newly synthesized bile in the liver.
  • 00:02:39
    Bile-binding resins adhere to negatively charged bile acids in small intestine, preventing
  • 00:02:45
    them from being reabsorbed, thus promoting their excretion.
  • 00:02:49
    As more bile is excreted in feces, the liver produces more new bile from cholesterol, effectively
  • 00:02:55
    removing more cholesterol from the blood.
  • 00:02:57
    These resins are best taken with meals.
  • 00:03:01
    Common side effects include nausea, bloating, and stomach cramping.
  • 00:03:05
    In addition, absorption of fat-soluble vitamins may be reduced; production of liver enzymes
  • 00:03:12
    may also increase.
  • 00:03:14
    Ezetimibe inhibits the absorption of dietary and biliary cholesterol from the small intestine
  • 00:03:20
    without affecting bile.
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    It is taken with meals.
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    Ezetimibe can cause fatigue, diarrhea, headache, runny nose, sore throat, body aches, and some
  • 00:03:31
    other more serious but less common side effects.
  • 00:03:36
    Fibrates are agonists for PPAR-alpha.
  • 00:03:39
    PPARs are transcription factors that mediate the effect of dietary fatty acids on lipoprotein
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    metabolism.
  • 00:03:47
    Activation of PPAR-alpha has several effects: it promotes degradation of triglyceride-rich
  • 00:03:53
    particles by lipoprotein lipase, it reduces production of VLDL, and increases production
  • 00:03:59
    of HDL by upregulating apolipoprotein A1 - the major protein component of HDL.
  • 00:04:07
    Fibrates are usually taken before meals.
  • 00:04:10
    Common side effects include indigestion, abdominal pain, fatigue, dizziness, leg cramp, and increased
  • 00:04:17
    serum creatinine.
  • 00:04:19
    PCSK9 inhibitors are monoclonal antibodies that bind to and inhibit PCSK9.
  • 00:04:26
    PCSK9 is an enzyme that promotes degradation of LDL receptors which are required for cellular
  • 00:04:33
    uptake of LDL from the blood.
  • 00:04:35
    Inhibition of PCSK9 increases LDL receptors, removing more LDL from blood plasma.
  • 00:04:43
    These drugs are administered by subcutaneous injections.
  • 00:04:47
    They can cause local injection site reactions such as erythema, pain, and bruising.
  • 00:04:54
    Niacin lowers plasma VLDL, LDL and triglyceride levels, and raises HDL significantly.
  • 00:05:03
    Proposed mechanisms include: decreased triglyceride synthesis, decreased degradation of apolipoprotein
  • 00:05:10
    A1, and increased activation of another PPAR, PPAR-gamma.
  • 00:05:14
    This drug is taken with meals.
  • 00:05:17
    Niacin is often poorly tolerated, with many side effects ranging from unpleasant to severe.
Tags
  • lipid-lowering
  • cholesterol
  • triglycerides
  • lipoproteins
  • statins
  • PCSK9 inhibitors
  • bile resins
  • ezetimibe
  • fibrates
  • niacin