Prevalite is the brand name for the generic medication cholestyramine resin, a type of drug known as a bile acid sequestrant. It is available as a powder for oral suspension that must be mixed with liquid before consumption. Its primary uses are to lower high cholesterol levels and to treat the intense itching associated with certain liver and bile duct diseases. This guide provides a comprehensive overview of how Prevalite works, its specific uses, potential side effects, and important considerations for patients.
How Prevalite Works: The Mechanism of a Bile Acid Sequestrant
Unlike statins, which prevent the liver from making cholesterol, Prevalite works locally within the gastrointestinal tract and is not absorbed into the bloodstream. Its mechanism of action can be understood through two key functions:
Binding to Bile Acids
After oral administration, the cholestyramine resin binds to bile acids in the small intestine, forming an insoluble complex. Normally, the body reabsorbs a large portion of these bile acids, which are made from cholesterol, to be reused. By binding to them, Prevalite prevents this reabsorption, and the bile acid-cholestyramine complex is excreted in the feces.
Lowering Cholesterol
To replace the lost bile acids, the liver must use more of the cholesterol circulating in the blood to synthesize new bile acids. This process leads to a reduction in the body's overall cholesterol levels, particularly the harmful low-density lipoprotein (LDL) cholesterol. The increase in the liver's demand for cholesterol ultimately lowers the amount found in the plasma.
Relieving Itching (Pruritus)
In conditions involving a partial blockage of the bile ducts, bile acids can build up in the body and deposit in the skin, causing severe itching. By binding to and removing bile acids, Prevalite helps to reduce the concentration of these substances in the skin tissues, providing significant relief from the pruritus.
Primary Medical Uses of Prevalite
Prevalite has two main FDA-approved indications, as well as some off-label uses for which it may be prescribed.
- High Cholesterol (Hypercholesterolemia): Prevalite is used as an adjunct to a proper diet and exercise program to reduce elevated serum cholesterol, particularly LDL. It is often prescribed for patients who cannot tolerate statins or for whom statins are not enough.
- Pruritus due to Partial Biliary Obstruction: For patients with liver conditions leading to an excess of bile acids, Prevalite effectively treats the associated itching. Relief can often be felt within days of starting therapy.
- Other Off-Label Uses: The medication is sometimes used to manage chronic diarrhea caused by bile acid malabsorption, which can occur after gallbladder removal or certain intestinal surgeries. It may also be used in cases of thyrotoxicosis to accelerate the removal of excess thyroid hormone.
Dosage and Administration
Prevalite is a powdered medication that requires careful preparation before ingestion.
- Mixing Instructions: The powder must be mixed with a sufficient amount of a non-carbonated beverage, such as water or juice. It can also be mixed into liquid soups, applesauce, or crushed pineapple. The key is to stir until the powder is completely mixed and then drink it immediately.
- Dosage Schedule: Prevalite is typically taken according to a schedule determined by a healthcare professional, depending on the condition being treated. It is important to adjust the dose gradually as directed to minimize gastrointestinal side effects.
- Maintaining Dental Hygiene: Prolonged contact with the teeth can cause discoloration or enamel erosion, so practicing good oral hygiene is essential.
Comparison of Prevalite and Statins
| Feature | Prevalite (Cholestyramine) | Statins (e.g., Atorvastatin, Rosuvastatin) |
|---|---|---|
| Drug Class | Bile Acid Sequestrant | HMG-CoA Reductase Inhibitor |
| Mechanism | Binds bile acids in the intestine, leading to increased cholesterol use by the liver. | Blocks the enzyme in the liver that produces cholesterol. |
| Absorption | Not absorbed into the bloodstream; acts locally in the gut. | Systemically absorbed and metabolized by the liver. |
| Effect on LDL | Reduces LDL cholesterol. | Highly effective at reducing LDL cholesterol. |
| Primary Use | Second-line treatment for high cholesterol or for statin-intolerant patients. Also for pruritus. | First-line treatment for most patients with high cholesterol. |
| Side Effects | Primarily gastrointestinal, including constipation, bloating, gas, and nausea. | May cause muscle pain, liver enzyme elevation, and increased blood sugar levels. |
| Drug Interactions | Binds to other oral medications in the intestine, reducing their absorption. | Metabolized by liver enzymes, leading to many potential interactions. |
Important Considerations and Potential Side Effects
Before taking Prevalite, it is crucial to discuss your full medical history with your doctor, including any other medications you take. Awareness of the potential side effects and interactions is key to a safe and effective treatment plan.
Common Side Effects
- Constipation: This is the most common side effect and can be managed by increasing fluid intake, consuming more fiber, or with a stool softener as recommended by a healthcare professional.
- Gastrointestinal Distress: Other common issues include bloating, gas, nausea, and stomach pain.
Severe Side Effects and Risks
- Intestinal Obstruction: In rare cases, especially with certain pre-existing bowel issues, severe constipation can lead to intestinal blockage.
- Fat-Soluble Vitamin Deficiency: Long-term use can reduce the absorption of fat-soluble vitamins (A, D, E, and K) and folic acid. A doctor may recommend vitamin supplements to counteract this effect.
- Increased Bleeding Risk: Vitamin K deficiency can lead to a higher risk of bleeding, especially in those on blood-thinning medications.
Drug Interactions
Because of its binding mechanism, Prevalite can interfere with the absorption of many other oral medications. To avoid this, it is generally recommended to take other drugs at a different time than Prevalite, typically several hours apart, as advised by a healthcare professional. Medications commonly affected include warfarin, thyroid preparations (like levothyroxine), and certain diuretics.
Conclusion
Prevalite is a vital medication for specific conditions, primarily high LDL cholesterol and cholestatic pruritus. As a bile acid sequestrant, its mechanism of action differs from statins, making it a valuable alternative or add-on therapy. Given its potential for drug interactions and common gastrointestinal side effects like constipation, adherence to administration instructions and open communication with a healthcare provider are essential. When used correctly as part of a comprehensive treatment plan that includes diet and exercise, Prevalite can be a highly effective medication for managing these health issues. To learn more about cholesterol management options, consult with your healthcare provider or visit the American Heart Association website.
