Atorvastatin

Atorvastatin - Use | Dose | Side Effects

Atorvastatin is a drug from the group of statins or HMG CoA reductase inhibitors. It works by blocking the enzyme that converts 3-hydroxy-3-methylglutaryl-coenzyme A to mevalonate which is a precursor of cholesterol. In this way, Atorvastatin decreases the concentration of cholesterol and lipoproteins (especially LDL) in the blood. Clinical trials showed that Atorvastatin can reduce total cholesterol by 30-45%, LDL cholesterol by 40-60% and triglycerides by 15-30%. Given that elevated cholesterol is common disease nowadays, Atorvastatin belongs to one of the most commonly used drugs worldwide.

Precautions

Contraindications to the use of Atorvastatin include:

  • Hypersensitivity to this drug or other statins
  • Active liver disease
  • Patients with history of statin-induced myopathy
  • Pregnancy and lactation

Special precautions should be taken in the following situations:

  • Hepatic impairment. Liver function tests should be performed before the initiation of treatment and periodically during the treatment. It is required to perform these tests every two weeks at the beginning of treatment. If levels of liver enzymes (AST and ALT) are three times higher than the upper reference limit, discontinuation of therapy should considered. Patients who consume large amounts of alcohol have an increased risk of liver damage.
  • Stroke. Patients who have had a history of stroke need to apply this drug cautiously because clinical trials have shown that Atorvastatin slightly increases the risk of stroke in patients who have already suffered a stroke.
  • Skeletal muscle damage. Like all other inhibitors of HMG CoA reductase, Atorvastatin can also cause damage to the skeletal muscles which then leads to renal damage. If you notice any changes in the muscle (muscle inflammation, muscle pain, muscle weakness or muscle cramps), inform your physician immediately.
  • Hypothyroidism. Use of statins in patients with hypothyroidism is dangerous, because these patients are more susceptible to muscle damage.1
  • Patients above the age of 65. The risk of muscle and liver damage is higher in elderly patients, so Atorvastatin must be applied cautiously in such patients.

Atorvastatin, pregnancy and breastfeeding

Atorvastatitn is contraindicated during pregnancy because studies have shown that certain congenital malformations may occur due to the use of statins.

It is also contraindicated during lactation. You should stop breastfeeding while using this drug.

Recommended dosage

The usual dose is 10 mg once a day. This dosage regimen is effective in most patients, but sometimes it is necessary to increase the dose in order to achieve desired effect. The maximum daily dose is 80 mg, but it should be used only in rare cases when extreme reduction of blood lipid concentration is necessary.

It can be used in children above the age of 10.

Swallow the tablet whole, regardless of the meal and at any time of day.

It usually takes 14 days for Atorvastatin to work, while the maximum effect is achieved after 4 weeks of treatment.

Interactions

Atorvastatin may interact with the following medications:

  • Antibiotics (e.g., telithromycin, azithromycin, roxithromycin, clarithromycin, erythromycin and others). These drugs inhibit the enzyme CYP3A4 which metabolizes Atorvastatin, which means that these medicines increase the concentration of Atorvastatin in the blood and this can lead to adverse effects.
  • Antifungal drugs (voriconazole, posaconazole, ketoconazole, fluconazole and itraconazole). These drugs also inhibit the enzyme CYP3A4.
  • Calcium antagonists (e.g. diltiazem and verapamil). These drugs are also inhibitors of the CYP3A4 enzyme.
  • Drugs used to treat tuberculosis (e.g. rifampin). These drugs are inducers of CYP3A4 enzyme, which means that they speed up the metabolism of the Atorvastatin and that means that they reduce its concentration in the blood and reduce its efficiency.
  • St. John's Wort (also an inducer of CYP3A4 enzyme).
  • Drugs used for HIV treatment (e.g. efavirenz). Efavirenz is also an inducer of CYP3A4 enzyme.
  • Other lipid-lowering drugs. Concomitant use with other lipid-lowering drugs increase the risk of liver and muscle damage.

Side effects

Atorvastatin is associated with the following side effects:

  • Inflammation of the nasal mucosa
  • Inflammation of pharynx
  • Thrombocytopenia
  • Hyperglycemia
  • Hypoglycemia
  • Insomnia
  • Headache
  • Hypoesthesia
  • Dysgeusia
  • Paraesthesia
  • Digestive disorders
  • Alopecia
  • Bullous dermatitis
  • Toxic epidermal necrolysis
  • Allergy

References

  1. NCBI link