Before we know the side Effects of Statins, First we will see what Statins are and how they work to lower our blood cholesterol levels.
What are Statins?
They are lipid-lowering medicine: a medicine that lowers blood cholesterol levels by inhibiting HMG-CoA reductase
Statins are a class of medicines that are frequently used to lower blood cholesterol levels. The drugs are able to block the action of a chemical in the liver that is necessary for making cholesterol. Although cholesterol is necessary for normal cell and body function, very high levels of it can lead to atherosclerosis, a condition where cholesterol-containing plaques build up in arteries and block blood flow. By reducing blood cholesterol levels, statins lower the risk of chest pain (angina), heart attack, and stroke.
Several types of statins exist such as atorvastatin, cerivastatin, fluvastatin, lovastatin, mevastatin, pitavastatin, pravastatin, rosuvastatin, and simvastatin. Atorvastatin and rosuvastatin are the most potent, while fluvastatin is the least potent. These medicines are sold under several different brand names including Lipitor (an atorvastatin), Pravachol (a pravastatin), Crestor (a rosuvastatin), Zocor (a simvastatin), Lescol (a fluvastatin) and Vytorin (a combination of simvastatin and ezetimibe). Mevastatin is a naturally occurring statin that is found in red yeast rice.
How do statins work?
Statins inhibit an enzyme called HMG-CoA reductase, which controls cholesterol production in the liver. The medicines actually act to replace the HMG-CoA that exists in the liver, thereby slowing down the cholesterol production process. Additional enzymes in the liver cell sense that cholesterol production has decreased and respond by creating a protein that leads to an increase in the production of LDL (low density lipoprotein, or "bad" cholesterol) receptors. These receptors relocate to the liver cell membranes and bind to passing LDL and VLDL (very low density lipoprotein). The LDL and VLDL then enter the liver and are digested.
Many people who begin statin treatment do so in order to lower their cholesterol level to less than 5 mmol/l, or by 25-30%. The dosage may be increased if this target is not reached. Treatment with the statin usually continues even after the target cholesterol level is reached in order to sustain atherosclerosis prevention.
Who takes statins?
Statins are usually prescribed to people who have the following conditions:
- Atheroma-related diseases such as heart disease and atherosclerosis. Statins reduce the chance that these conditions will worsen and can delay progression of the diseases.
- Diabetes or another disease that increases the risk of developing an atheroma related disease
- A family history of heart attacks (especially at a young age)
- Increasing age
A high cholesterol level is the most common reason that a person is placed on statins, but the drugs also reduce heart diseases by preventing atherosclerosis. In fact, it is possible to have a heart attack without high blood cholesterol levels, but nearly all heart attacks begin with atherosclerosis plaque buildup. Plaques from atherosclerosis can still form even when blood cholesterol is low. Therefore, statins may be used to treat people who have or are at a higher risk of atherosclerosis even if they do not have high cholesterol levels.
New Research- Side Effects of Statins
In a study of more than 1,000 adults, researchers at the University of California, San Diego, found that individuals taking cholesterol-lowering statin drugs are more likely than non-users to experience decreased energy, fatigue upon exertion, or both. The researchers suggest that these findings should be taken into account by doctors when weighing risk versus benefit in prescribing statins.
Statin drugs are among the best-selling and most widely used prescription drugs on the market. Recently, increasing attention has focused on statins' side effects, particularly their effect on exercise. While some patients have reported fatigue or exercise intolerance when placed on statins, randomized trials had not previously addressed occurrence of fatigue-with-exertion or impaired energy in patients on statins relative to placebo. In Archives of Internal Medicine Beatrice Golomb, MD, PhD, associate professor of medicine at UC San Diego School of Medicine, and colleagues present randomized trial data which show that these side effects were significantly greater in persons placed on statins than those on a placebo.
More than 1,000 adults from San Diego were randomly allocated to identical capsules with placebo, or one of two statins at relatively low potencies: pravastatin (Pravachol) at 40mg, or simvastatin (Zocor) at 20mg - chosen as the most water-soluble and most fat-soluble of the statins, at doses expected to produce similar LDL ("bad cholesterol") reduction. According to the researchers, the cholesterol reduction would be similar to that expected with atorvastatin (Lipitor) at 10mg, or rosuvastatin (Crestor) at 2.5-5mg.
Persons with heart disease and diabetes were excluded. Neither subjects nor investigators knew which agent the subject had received. Subjects rated their energy and fatigue with exertion relative to baseline, on a five-point scale, from "much worse" to "much better." Those placed on statins were significantly more likely than those on placebo to report worsening in energy, fatigue-with-exertion, or both. Both statins contributed to the finding, though the effect appeared to be stronger in those on simvastatin. (Simvastatin led to significantly greater cholesterol reduction.) "Side effects of statins generally rise with increasing dose, and these doses were modest by current standards," said Golomb. "Yet occurrence of this problem was not rare - even at these doses, and particularly in women.
The magnitude of the effect observed can be seen in the research findings if, for example, 4 of 10 treated women on simvastatin cited worsened energy or exertional fatigue; 2 in 10 cited worsening in both, or rated either one as "much worse"; or if 1 in 10 study participants rated energy and exertional fatigue as "much worse." "Energy is central to quality of life. It also predicts interest in activity," said Golomb. "Exertional fatigue not only predicts actual participation in exercise, but both lower energy and greater exertional fatigue may signal triggering of mechanisms by which statins may adversely affect cell health."
For these reasons, the researchers state that decreases in energy, and increases in exertional fatigue on statins represent important findings which should be taken into account in risk-benefit determinations for statins. According to Golomb, this is particularly true for groups for whom evidence does not support mortality benefit on statins - such as most patients without heart disease, and women and those over 70 or 75, even if heart disease is present.
(Source- Archives of Internal Medicine)
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