Hydroxychloroquine, known by the brand names Plaquenil® and Sovuna®, is a disease-modifying anti-rheumatic drug (DMARD) used to treat several conditions by modulating the immune system. While its origins are tied to treating malaria, its utility for autoimmune disorders has been well-documented for decades.
Primary Reasons for Hydroxychloroquine Prescription
Your doctor likely prescribed hydroxychloroquine for an autoimmune disease or a related condition, not for its original antimalarial purpose in most cases. The most common reasons include:
- Rheumatoid Arthritis (RA): This chronic inflammatory disorder causes joint pain, swelling, and stiffness. Hydroxychloroquine is prescribed to reduce inflammation, alleviate these symptoms, and help prevent long-term joint damage. For RA, it can take several weeks to months to see the full benefit.
- Systemic Lupus Erythematosus (SLE) and Discoid Lupus (DLE): As a first-line treatment for lupus, the drug is used to manage and prevent flares, reduce inflammation, and help protect against organ damage. A significant finding noted by the Lupus Foundation of America is that patients with lupus who take hydroxychloroquine tend to live longer than those who do not.
- Other Related Conditions: The medication is sometimes used for conditions like Sjögren's syndrome, porphyria cutanea tarda (a type of blood disorder affecting the skin), and certain skin conditions sensitive to light.
How Hydroxychloroquine Works
Unlike a simple painkiller, hydroxychloroquine works gradually to modify the underlying disease process. Its mechanism of action is complex and not fully understood, but it is believed to work by calming an overactive immune system. The key actions include:
- Affecting Immune Cells: It interferes with communication signals within the immune system, helping to reduce the inflammatory response that drives autoimmune diseases.
- Suppressing T-cells: It helps suppress the function of certain T-lymphocytes (T-cells), which are involved in the attack on the body's own tissues.
- Blocking Toll-like Receptors (TLRs): Some research suggests it suppresses TLRs, which are part of the innate immune system and can trigger inflammatory pathways involved in diseases like lupus.
Important Safety Information and Monitoring
While generally well-tolerated, particularly at lower doses, hydroxychloroquine requires careful medical supervision, especially with long-term use.
Potential Side Effects
- Common side effects: Nausea, diarrhea, stomach cramps, headache, loss of appetite, and changes in hair color. Many of these can be minimized by taking the medication with food.
- Rare but serious side effects:
- Retinopathy: This is a rare, but serious, vision-related side effect that can affect the retina. The risk is dose-dependent and increases with long-term use. Regular eye exams with an ophthalmologist are recommended to monitor for early signs of toxicity.
- Cardiomyopathy: Chronic use at high cumulative doses has been linked to a rare heart muscle condition.
- Hypoglycemia (Low Blood Sugar): Hydroxychloroquine can cause low blood sugar, so your doctor may ask you to monitor your levels.
- Skin Changes: Rashes, itching, or hyperpigmentation can occur.
- Neuropsychiatric Effects: Very rarely, changes in mood, depression, or suicidal ideation can occur.
Contraindications and Precautions
Your doctor will assess your medical history before prescribing this medication. It should be used with caution or avoided in people with:
- Pre-existing eye conditions affecting the retina.
- Psoriasis, which may worsen with this medication.
- Glucose-6-phosphate dehydrogenase (G6PD) deficiency.
- Liver, kidney, or heart problems.
Hydroxychloroquine vs. Other Autoimmune Medications
Your doctor may have chosen hydroxychloroquine due to its safety profile, effectiveness for specific symptoms, and long-term benefits compared to other options. Here's a quick comparison with some other common treatments:
| Feature | Hydroxychloroquine (Plaquenil) | Methotrexate | Biologic DMARDs (e.g., Humira) |
|---|---|---|---|
| How it Works | Modulates the immune system by affecting cellular pathways. | Acts as an antimetabolite, blocking an enzyme critical for cell growth. | Target specific parts of the immune system, such as TNF-alpha. |
| Main Uses | Lupus, Rheumatoid Arthritis, Malaria prevention. | RA, Psoriasis, certain cancers. | RA, Psoriatic Arthritis, Crohn's Disease, Ankylosing Spondylitis. |
| Onset of Action | Slow, typically taking 1-6 months for full effect. | Faster than HCQ, often within 4-6 weeks. | Variable, some can be fast-acting. |
| Common Side Effects | Nausea, diarrhea, headache, visual changes (rare, long-term). | Nausea, fatigue, liver toxicity, mouth sores. | Injection site reactions, increased infection risk, headaches. |
| Pregnancy | Generally considered safe for use during pregnancy for autoimmune diseases. | Not safe during pregnancy. | Safety varies; discussion with doctor is crucial. |
Important Clarification: The COVID-19 Context
During the COVID-19 pandemic, hydroxychloroquine received widespread and controversial media attention. It is critical to understand that major health organizations, including the FDA and the World Health Organization (WHO), recommend against using hydroxychloroquine for the treatment of COVID-19 outside of clinical trials. Numerous studies, including the large RECOVERY trial, found no benefit for hospitalized COVID-19 patients and highlighted potential serious side effects, such as heart rhythm problems. This misinformation has no bearing on its established and safe use for autoimmune diseases under a doctor's care.
Conclusion
Your doctor likely prescribed hydroxychloroquine because it is a proven, long-standing, and effective treatment for your specific autoimmune condition, such as lupus or rheumatoid arthritis. By modulating the immune system, it works to control inflammation, reduce symptoms, and prevent disease progression. While its action is slow, consistent use under your doctor's supervision—including regular eye exams—is crucial for its benefits and safety. If you have any concerns or questions about your treatment, always discuss them with your healthcare provider.
