HMG CoA reductase Inhibitors learn @ a glance
Published at : November 13, 2021
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HMG CoA Reductase Inhibitors: They inhibit the synthesis of cholesterol in the liver. Cholesterol synthesis involves a number of reactions, out of which HMG CoA to mevalonic acid represents a rate-limiting step. This step is stimulated by HMG CoA Reductase. HMG CoA reductase inhibitors inhibit HMG CoA reductase and reduce the synthesis of cholesterol in the liver. The reduction in cholesterol in the liver demands more cholesterol for the synthesis of bile acids and steroidal hormones for which LDL receptors (on the surface of the liver) are activated; consequently, LDL from plasma comes to the liver by endocytosis.
Note:
• Among statins, lovastatin, and simvastatin are inactive lactone prodrugs. They are converted to their active forms in the liver. Pitavastatin is the more potent statin.
• Lovastatin should not be administered with digoxin, as lovastatin decreases gastrointestinal absorption of digoxin and interrupt the enterohepatic circulation of digoxin.
• activity of HMG CoA reductase is maximum at night, so these drugs are administered at night. Rosuvastatin and atorvastatin are long-acting drugs, therefore can be administered at any time of the day.
Common Dosages:
1. Fluvastatin: 20-80mg is given PO daily; with an evening meal.
2. Lovastatin: 10-80mg is given PO, QHS (QHS: every night at bedtime).
3. Atorvastatin: 20-80mg is given PO daily; with an evening meal.
4. Simvastatin: 10-40mg is given PO daily; with an evening meal.
5. Rosuvastatin: 5-40mg is given PO daily (contraindicated 40 mg dose in patients predisposed to myopathy/rhabdomyolysis).
6. Pravastatin: 10-40mg is given PO daily.
Adverse Effects
1. Common: Myalgia, abdominal pain, constipation, elevated transaminases, headache, rash, sleep disturbance.
2. Rare: Hepatotoxicity, rhabdomyolysis, peripheral neuropathy, lupus-like symptoms, and impotence.
3. More: side effects with lipophilic agents such as atorvastatin, lovastatin, and simvastatin (Fluvastatin, pravastatin, and rosuvastatin are hydrophilic).
HMG CoA Reductase Inhibitors: They inhibit the synthesis of cholesterol in the liver. Cholesterol synthesis involves a number of reactions, out of which HMG CoA to mevalonic acid represents a rate-limiting step. This step is stimulated by HMG CoA Reductase. HMG CoA reductase inhibitors inhibit HMG CoA reductase and reduce the synthesis of cholesterol in the liver. The reduction in cholesterol in the liver demands more cholesterol for the synthesis of bile acids and steroidal hormones for which LDL receptors (on the surface of the liver) are activated; consequently, LDL from plasma comes to the liver by endocytosis.
Note:
• Among statins, lovastatin, and simvastatin are inactive lactone prodrugs. They are converted to their active forms in the liver. Pitavastatin is the more potent statin.
• Lovastatin should not be administered with digoxin, as lovastatin decreases gastrointestinal absorption of digoxin and interrupt the enterohepatic circulation of digoxin.
• activity of HMG CoA reductase is maximum at night, so these drugs are administered at night. Rosuvastatin and atorvastatin are long-acting drugs, therefore can be administered at any time of the day.
Common Dosages:
1. Fluvastatin: 20-80mg is given PO daily; with an evening meal.
2. Lovastatin: 10-80mg is given PO, QHS (QHS: every night at bedtime).
3. Atorvastatin: 20-80mg is given PO daily; with an evening meal.
4. Simvastatin: 10-40mg is given PO daily; with an evening meal.
5. Rosuvastatin: 5-40mg is given PO daily (contraindicated 40 mg dose in patients predisposed to myopathy/rhabdomyolysis).
6. Pravastatin: 10-40mg is given PO daily.
Adverse Effects
1. Common: Myalgia, abdominal pain, constipation, elevated transaminases, headache, rash, sleep disturbance.
2. Rare: Hepatotoxicity, rhabdomyolysis, peripheral neuropathy, lupus-like symptoms, and impotence.
3. More: side effects with lipophilic agents such as atorvastatin, lovastatin, and simvastatin (Fluvastatin, pravastatin, and rosuvastatin are hydrophilic).
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