Hydroxychloroquine 300mg Tablets
It is used to treat or prevent malaria. It is used to treat lupus.It is used to treat rheumatoid arthritis.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Antimalarial, Disease-Modifying Antirheumatic Drug (DMARD)
Pharmacologic Class
Aminoquinoline
Pregnancy Category
Not available
FDA Approved
Mar 1955
DEA Schedule
Not Controlled
Overview
What is this medicine?
Hydroxychloroquine is a medication used to treat certain autoimmune diseases like lupus and rheumatoid arthritis, and also to prevent or treat malaria. It works by calming down the overactive immune system in autoimmune conditions and by killing the malaria parasite.
How to Use This Medicine
Taking Your Medication Correctly
To ensure you get the most out of your medication, follow these steps:
Take your medication exactly as directed by your doctor. Read all the information provided with your prescription and follow the instructions carefully.
For all uses of this medication:
+ Take your dose with food or milk to help your body absorb the medication.
+ Swallow the tablet whole - do not chew, break, or crush it.
+ Continue taking your medication as prescribed by your doctor or healthcare provider, even if you start to feel better.
+ Avoid taking antacids or kaolin within 4 hours of taking this medication, as they may interfere with its effectiveness.
If you are taking this medication to prevent malaria:
+ Make sure you understand when to start taking your medication. If you're unsure, consult with your doctor.
Storing and Disposing of Your Medication
To keep your medication safe and effective:
Store your medication at room temperature in a dry place, away from the bathroom.
Keep all medications out of reach of children and pets.
Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so by your pharmacist.
Check with your pharmacist for guidance on the best way to dispose of your medication. You may also have access to drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose of your medication:
Take the missed dose as soon as you remember.
If it's close to the time for your next dose, skip the missed dose and resume your regular schedule.
Do not take two doses at the same time or take extra doses to make up for a missed one.
To ensure you get the most out of your medication, follow these steps:
Take your medication exactly as directed by your doctor. Read all the information provided with your prescription and follow the instructions carefully.
For all uses of this medication:
+ Take your dose with food or milk to help your body absorb the medication.
+ Swallow the tablet whole - do not chew, break, or crush it.
+ Continue taking your medication as prescribed by your doctor or healthcare provider, even if you start to feel better.
+ Avoid taking antacids or kaolin within 4 hours of taking this medication, as they may interfere with its effectiveness.
If you are taking this medication to prevent malaria:
+ Make sure you understand when to start taking your medication. If you're unsure, consult with your doctor.
Storing and Disposing of Your Medication
To keep your medication safe and effective:
Store your medication at room temperature in a dry place, away from the bathroom.
Keep all medications out of reach of children and pets.
Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so by your pharmacist.
Check with your pharmacist for guidance on the best way to dispose of your medication. You may also have access to drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose of your medication:
Take the missed dose as soon as you remember.
If it's close to the time for your next dose, skip the missed dose and resume your regular schedule.
Do not take two doses at the same time or take extra doses to make up for a missed one.
Lifestyle & Tips
- Take this medication exactly as prescribed by your doctor. Do not stop taking it without consulting your doctor, even if you feel better.
- Take with food or milk to reduce stomach upset.
- Protect your skin from the sun, as this medication can increase sun sensitivity.
- Attend all scheduled eye exams and blood tests as recommended by your doctor. These are very important to monitor for side effects.
- Report any new or worsening vision changes immediately to your doctor.
- Avoid alcohol or use in moderation, as it may increase the risk of liver problems.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
For chronic use (e.g., SLE, RA): 200 mg to 400 mg daily, or 6.5 mg/kg ideal body weight, whichever is lower. For 300mg tablets, typically 300mg once daily or 300mg every other day depending on total daily dose.
Dose Range:
200 - 400 mg
Condition-Specific Dosing:
Systemic Lupus Erythematosus (SLE):
Initial: 400 mg daily or BID for 1-2 weeks. Maintenance: 200-400 mg daily. Max: 6.5 mg/kg/day ideal body weight.
Rheumatoid Arthritis (RA):
Initial: 400 mg daily or BID for 4-12 weeks. Maintenance: 200-400 mg daily. Max: 6.5 mg/kg/day ideal body weight.
Malaria (Acute Treatment):
Initial: 800 mg (base) once, then 400 mg (base) at 6, 24, and 48 hours after initial dose. Total 2000 mg (base). (Note: 300mg tablet is 232.5mg base).
Malaria (Prophylaxis):
400 mg (base) once weekly, starting 1-2 weeks before exposure, continuing for 4 weeks after leaving endemic area.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
For SLE/JIA: 3-6.5 mg/kg/day (ideal body weight) orally, not to exceed 400 mg/day or 6.5 mg/kg/day, whichever is lower. For Malaria (Acute Treatment): 10 mg/kg (base) initial dose, then 5 mg/kg (base) at 6, 24, and 48 hours after initial dose. Total 25 mg/kg (base). For Malaria (Prophylaxis): 6.5 mg/kg (base) once weekly, not to exceed 400 mg (base) weekly.
Adolescent:
Same as adult dosing for chronic conditions (SLE/RA) based on weight. Malaria dosing as per child/adult weight-based guidelines.
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment generally required, but monitor closely.
Moderate:
Consider dose reduction (e.g., 50%) or increased dosing interval (e.g., every other day) if CrCl < 50 mL/min. Monitor for toxicity.
Severe:
Significant dose reduction (e.g., 50% or more) or increased dosing interval (e.g., 2-3 times per week) recommended if CrCl < 30 mL/min. Avoid if possible.
Dialysis:
Hydroxychloroquine is not significantly removed by dialysis. Dose adjustment based on residual renal function.
Hepatic Impairment:
Mild:
No specific adjustment generally required, but monitor closely.
Moderate:
Use with caution. Consider dose reduction or increased dosing interval. Monitor for toxicity.
Severe:
Use with extreme caution or avoid. Significant dose reduction or increased dosing interval likely required. Monitor for toxicity.
Pharmacology
Mechanism of Action
Hydroxychloroquine is an antimalarial and immunomodulatory agent. In malaria, it concentrates in the parasite's food vacuole, inhibiting heme detoxification and leading to accumulation of toxic heme, killing the parasite. In autoimmune diseases like RA and SLE, its exact mechanism is not fully understood but involves multiple effects: interference with lysosomal activity and antigen presentation in immune cells, inhibition of toll-like receptor (TLR) signaling (especially TLR9), reduction of cytokine production (e.g., TNF-alpha, IL-1, IL-6), and stabilization of lysosomal membranes.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 74%
Tmax:
Approximately 3-4 hours (for parent drug), but active metabolites can peak later.
FoodEffect:
Absorption may be slightly increased with food, but can be taken with or without food.
Distribution:
Vd:
Very large (580-815 L/kg), indicating extensive tissue distribution, especially in highly pigmented tissues (retina, skin, liver, kidney, spleen, lung).
ProteinBinding:
Approximately 45-50%
CnssPenetration:
Limited, but can cross the blood-brain barrier.
Elimination:
HalfLife:
Terminal elimination half-life is very long, ranging from 32 to 50 days (for parent drug and metabolites).
Clearance:
Not readily available as a single rate due to extensive tissue distribution and long half-life.
ExcretionRoute:
Renal (primarily) and hepatic/biliary.
Unchanged:
Approximately 16-25% of the dose is excreted unchanged in urine.
Pharmacodynamics
OnsetOfAction:
Antimalarial: Rapid (hours). Autoimmune diseases: Slow, typically 4-12 weeks for clinical effect, sometimes up to 6 months.
PeakEffect:
Antimalarial: Within days. Autoimmune diseases: Several months.
DurationOfAction:
Very long, due to extensive tissue binding and slow elimination.
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of liver problems, including:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Signs of kidney problems, such as:
+ Inability to pass urine
+ Changes in urine output
+ Blood in the urine
+ Sudden weight gain
Signs of low blood sugar, including:
+ Dizziness
+ Headache
+ Feeling sleepy or weak
+ Shaking
+ Fast heartbeat
+ Confusion
+ Hunger
+ Sweating
Seizures
New or worsening behavior or mood changes, such as depression or thoughts of suicide
Confusion
Hallucinations (seeing or hearing things that are not there)
Bad dreams
Ringing in the ears, hearing loss, or changes in hearing
Balance problems
Trouble controlling body movements
Shakiness
Muscle weakness
Uncontrolled eye movements
Eye problems, including:
+ Blurred or foggy vision
+ Trouble focusing or reading
+ Difficulty seeing in dim light
+ Loss of vision
+ Seeing dark spots or only part of an object
Heart problems, such as:
+ Heart failure
+ Abnormal heartbeat (prolonged QT interval)
+ Fast or irregular heartbeat
+ Severe dizziness or fainting
+ Shortness of breath
+ Sudden weight gain or swelling in the arms or legs
Low blood cell counts, which can increase the risk of:
+ Infections
+ Bleeding problems
+ Anemia
+ Fever
+ Chills
+ Sore throat
+ Unexplained bruising or bleeding
+ Feeling very tired or weak
Severe skin reactions, including:
+ Stevens-Johnson syndrome (SJS)
+ Toxic epidermal necrolysis (TEN)
+ Red, swollen, blistered, or peeling skin
+ Red or irritated eyes
+ Sores in the mouth, throat, nose, eyes, genitals, or skin
+ Fever
+ Chills
+ Body aches
+ Shortness of breath
+ Swollen glands
Other Possible Side Effects
Most people do not experience severe side effects, and some may only have minor side effects. However, if you notice any of the following symptoms, contact your doctor or seek medical attention if they bother you or do not go away:
Dizziness
Tiredness
Weakness
Headache
Nervousness or excitability
Diarrhea
Stomach pain
Upset stomach
Vomiting
Decreased appetite
Weight loss
Changes in skin color
Changes in hair color
* Hair loss
Reporting Side Effects
If you have questions about side effects or want to report a side effect, contact your doctor or call the FDA at 1-800-332-1088. You can also report side effects online at https://www.fda.gov/medwatch.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of liver problems, including:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Signs of kidney problems, such as:
+ Inability to pass urine
+ Changes in urine output
+ Blood in the urine
+ Sudden weight gain
Signs of low blood sugar, including:
+ Dizziness
+ Headache
+ Feeling sleepy or weak
+ Shaking
+ Fast heartbeat
+ Confusion
+ Hunger
+ Sweating
Seizures
New or worsening behavior or mood changes, such as depression or thoughts of suicide
Confusion
Hallucinations (seeing or hearing things that are not there)
Bad dreams
Ringing in the ears, hearing loss, or changes in hearing
Balance problems
Trouble controlling body movements
Shakiness
Muscle weakness
Uncontrolled eye movements
Eye problems, including:
+ Blurred or foggy vision
+ Trouble focusing or reading
+ Difficulty seeing in dim light
+ Loss of vision
+ Seeing dark spots or only part of an object
Heart problems, such as:
+ Heart failure
+ Abnormal heartbeat (prolonged QT interval)
+ Fast or irregular heartbeat
+ Severe dizziness or fainting
+ Shortness of breath
+ Sudden weight gain or swelling in the arms or legs
Low blood cell counts, which can increase the risk of:
+ Infections
+ Bleeding problems
+ Anemia
+ Fever
+ Chills
+ Sore throat
+ Unexplained bruising or bleeding
+ Feeling very tired or weak
Severe skin reactions, including:
+ Stevens-Johnson syndrome (SJS)
+ Toxic epidermal necrolysis (TEN)
+ Red, swollen, blistered, or peeling skin
+ Red or irritated eyes
+ Sores in the mouth, throat, nose, eyes, genitals, or skin
+ Fever
+ Chills
+ Body aches
+ Shortness of breath
+ Swollen glands
Other Possible Side Effects
Most people do not experience severe side effects, and some may only have minor side effects. However, if you notice any of the following symptoms, contact your doctor or seek medical attention if they bother you or do not go away:
Dizziness
Tiredness
Weakness
Headache
Nervousness or excitability
Diarrhea
Stomach pain
Upset stomach
Vomiting
Decreased appetite
Weight loss
Changes in skin color
Changes in hair color
* Hair loss
Reporting Side Effects
If you have questions about side effects or want to report a side effect, contact your doctor or call the FDA at 1-800-332-1088. You can also report side effects online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Any changes in vision (blurred vision, difficulty reading, blind spots, halos around lights, changes in color vision)
- Muscle weakness, numbness, or tingling
- Hearing loss or ringing in the ears (tinnitus)
- Severe skin rash, itching, or unusual skin discoloration
- Unexplained fever, sore throat, or signs of infection
- Unusual bleeding or bruising
- Severe dizziness, fainting, or irregular heartbeat
- Severe nausea, vomiting, or diarrhea
- Yellowing of the skin or eyes (jaundice), dark urine, or pale stools (signs of liver problems)
- Signs of low blood sugar (shakiness, sweating, confusion, hunger)
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following conditions to ensure safe treatment:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Describe the allergic reaction and its symptoms.
A history of abnormal heart rhythms, including a prolonged QT interval on an electrocardiogram (ECG).
Certain health conditions, such as:
+ Low levels of magnesium or potassium in your blood.
+ A slow heartbeat.
Other health issues, including:
+ Eye problems like retinopathy.
+ Heart failure (a weakened heart).
+ A history of heart attack.
Any changes in your vision or eye health that have occurred while taking this medication or similar drugs.
Certain medical conditions, such as porphyria or psoriasis.
Concurrent use of specific medications, including:
+ Cimetidine.
+ Rifampicin.
+ Drugs that can cause abnormal heart rhythms (prolonged QT interval). There are many medications that can have this effect; consult your doctor or pharmacist if you are unsure.
To ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking.
Any natural products or vitamins you are using.
Your complete medical history, including all health problems.
Before starting, stopping, or changing the dose of any medication, consult your doctor to confirm that it is safe to do so in conjunction with this medication.
It is essential to inform your doctor about the following conditions to ensure safe treatment:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Describe the allergic reaction and its symptoms.
A history of abnormal heart rhythms, including a prolonged QT interval on an electrocardiogram (ECG).
Certain health conditions, such as:
+ Low levels of magnesium or potassium in your blood.
+ A slow heartbeat.
Other health issues, including:
+ Eye problems like retinopathy.
+ Heart failure (a weakened heart).
+ A history of heart attack.
Any changes in your vision or eye health that have occurred while taking this medication or similar drugs.
Certain medical conditions, such as porphyria or psoriasis.
Concurrent use of specific medications, including:
+ Cimetidine.
+ Rifampicin.
+ Drugs that can cause abnormal heart rhythms (prolonged QT interval). There are many medications that can have this effect; consult your doctor or pharmacist if you are unsure.
To ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking.
Any natural products or vitamins you are using.
Your complete medical history, including all health problems.
Before starting, stopping, or changing the dose of any medication, consult your doctor to confirm that it is safe to do so in conjunction with this medication.
Precautions & Cautions
Important Warnings and Cautions
When taking this medication, it is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, about your treatment. Regular monitoring is crucial, so be sure to undergo blood tests, eye exams, and electrocardiograms (ECGs) as directed by your doctor to assess your heart rhythm.
If you have a deficiency of the enzyme glucose-6-phosphate dehydrogenase (G6PD), you may be at increased risk of developing anemia. This deficiency is more common in individuals of African, South Asian, Middle Eastern, and Mediterranean descent. Your doctor will closely monitor your condition to prevent any potential complications.
This medication may increase your sensitivity to sunlight, making you more prone to sunburn. Take necessary precautions when exposed to the sun, and notify your doctor if you experience any unusual sunburn or skin reactions.
There is a risk of hypoglycemia (low blood sugar) associated with this medication, which can be severe and potentially life-threatening. It is crucial to monitor your blood sugar levels regularly, as advised by your doctor, and discuss any concerns or symptoms with them promptly.
Before consuming alcohol, consult your doctor to understand any potential risks or interactions. Additionally, keep this medication out of reach of children, as accidental ingestion can be fatal. If a child accidentally takes this medication, seek immediate medical attention.
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects. Pregnant or breastfeeding women should discuss the benefits and risks of this medication with their doctor before taking it.
Preventing Malaria
When using this medication to prevent malaria, it is essential to combine it with other preventive measures, including:
Using window screens and bed nets
Applying insect repellents containing 10% to 35% DEET
Spraying permethrin on clothing and nets (avoid spraying insect repellents on children)
Minimizing outdoor activities during evening and nighttime hours
If you experience a fever while in or after leaving a malaria-infested area, contact your doctor immediately. Pregnant women traveling to areas with malaria should consult their doctor before taking this medication to discuss the potential risks and benefits.
When taking this medication, it is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, about your treatment. Regular monitoring is crucial, so be sure to undergo blood tests, eye exams, and electrocardiograms (ECGs) as directed by your doctor to assess your heart rhythm.
If you have a deficiency of the enzyme glucose-6-phosphate dehydrogenase (G6PD), you may be at increased risk of developing anemia. This deficiency is more common in individuals of African, South Asian, Middle Eastern, and Mediterranean descent. Your doctor will closely monitor your condition to prevent any potential complications.
This medication may increase your sensitivity to sunlight, making you more prone to sunburn. Take necessary precautions when exposed to the sun, and notify your doctor if you experience any unusual sunburn or skin reactions.
There is a risk of hypoglycemia (low blood sugar) associated with this medication, which can be severe and potentially life-threatening. It is crucial to monitor your blood sugar levels regularly, as advised by your doctor, and discuss any concerns or symptoms with them promptly.
Before consuming alcohol, consult your doctor to understand any potential risks or interactions. Additionally, keep this medication out of reach of children, as accidental ingestion can be fatal. If a child accidentally takes this medication, seek immediate medical attention.
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects. Pregnant or breastfeeding women should discuss the benefits and risks of this medication with their doctor before taking it.
Preventing Malaria
When using this medication to prevent malaria, it is essential to combine it with other preventive measures, including:
Using window screens and bed nets
Applying insect repellents containing 10% to 35% DEET
Spraying permethrin on clothing and nets (avoid spraying insect repellents on children)
Minimizing outdoor activities during evening and nighttime hours
If you experience a fever while in or after leaving a malaria-infested area, contact your doctor immediately. Pregnant women traveling to areas with malaria should consult their doctor before taking this medication to discuss the potential risks and benefits.
Overdose Information
Overdose Symptoms:
- Headache
- Drowsiness
- Blurred vision
- Nausea, vomiting
- Cardiac arrhythmias (e.g., QT prolongation, Torsades de Pointes)
- Hypotension
- Seizures
- Respiratory depression
- Cardiovascular collapse
- Hypokalemia
- Death
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Treatment is supportive and may include gastric lavage, activated charcoal, and management of cardiac arrhythmias, hypotension, and hypokalemia. Diazepam may be used for seizures.
Drug Interactions
Major Interactions
- Amiodarone (increased risk of QT prolongation, arrhythmias)
- Digoxin (increased digoxin levels, monitor)
- Drugs that prolong QT interval (e.g., antiarrhythmics Class IA and III, antipsychotics, tricyclic antidepressants, macrolide antibiotics, fluoroquinolones, azole antifungals) - increased risk of ventricular arrhythmias including Torsades de Pointes.
- Insulin and oral hypoglycemics (enhanced hypoglycemic effect)
- Mefloquine (increased risk of seizures)
- Tamoxifen (increased risk of retinopathy)
Moderate Interactions
- Antacids/Kaolin (decreased hydroxychloroquine absorption, separate administration by at least 4 hours)
- Cyclosporine (increased cyclosporine levels)
- Cimetidine (may inhibit metabolism, increasing hydroxychloroquine levels)
- Praziquantel (decreased praziquantel levels)
- Vaccines (live attenuated vaccines: theoretical decreased immune response, though generally considered safe for most non-immunosuppressed patients on HCQ)
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Ophthalmologic examination (visual acuity, fundoscopy, automated visual fields, spectral domain optical coherence tomography (SD-OCT))
Rationale: To establish baseline and detect pre-existing retinopathy or maculopathy, as hydroxychloroquine can cause irreversible retinal damage.
Timing: Prior to initiation of therapy.
Complete Blood Count (CBC) with differential
Rationale: To establish baseline and monitor for potential hematologic abnormalities (e.g., agranulocytosis, aplastic anemia, thrombocytopenia) which are rare but serious side effects.
Timing: Prior to initiation of therapy.
Liver Function Tests (LFTs)
Rationale: To establish baseline and monitor for potential hepatotoxicity.
Timing: Prior to initiation of therapy.
Renal Function Tests (Creatinine, BUN)
Rationale: To establish baseline and guide dose adjustments in patients with renal impairment.
Timing: Prior to initiation of therapy.
Electrocardiogram (ECG)
Rationale: To establish baseline QT interval, especially in patients with pre-existing cardiac conditions or those on other QT-prolonging medications.
Timing: Prior to initiation of therapy, if risk factors present.
Routine Monitoring
Ophthalmologic examination (visual acuity, fundoscopy, automated visual fields, SD-OCT)
Frequency: Annually after 5 years of therapy, or sooner if risk factors for retinopathy (e.g., daily dose > 5 mg/kg actual body weight, renal/hepatic impairment, concomitant tamoxifen use, pre-existing macular disease) are present. High-risk patients may need annual screening from baseline.
Target: Normal retinal structure and function.
Action Threshold: Any new visual changes, scotomas, or retinal abnormalities detected on exam warrant immediate discontinuation and referral to ophthalmologist.
Complete Blood Count (CBC) with differential
Frequency: Periodically (e.g., every 3-6 months) or as clinically indicated.
Target: Within normal limits.
Action Threshold: Significant decrease in cell counts (e.g., leukopenia, thrombocytopenia) warrants investigation and potential discontinuation.
Liver Function Tests (LFTs)
Frequency: Periodically (e.g., every 3-6 months) or as clinically indicated.
Target: Within normal limits.
Action Threshold: Significant elevation of liver enzymes warrants investigation and potential discontinuation.
Renal Function Tests (Creatinine, BUN)
Frequency: Periodically (e.g., every 3-6 months) or as clinically indicated, especially if renal impairment is present.
Target: Within normal limits or stable for patient.
Action Threshold: Significant decline in renal function may necessitate dose adjustment.
Electrocardiogram (ECG)
Frequency: As clinically indicated, especially if new cardiac symptoms develop or if patient is on other QT-prolonging drugs.
Target: Normal QT interval.
Action Threshold: QTc prolongation > 500 ms or increase of > 60 ms from baseline warrants discontinuation.
Symptom Monitoring
- Visual changes (blurred vision, difficulty reading, light sensitivity, halos, blind spots, color vision changes)
- Muscle weakness or atrophy
- Hearing loss or tinnitus
- Skin rash, itching, or pigmentation changes
- Nausea, vomiting, diarrhea, abdominal cramps
- Headache, dizziness, nervousness
- Unusual bleeding or bruising, signs of infection (fever, sore throat)
- Signs of hypoglycemia (sweating, tremor, confusion)
Special Patient Groups
Pregnancy
Hydroxychloroquine is generally considered compatible with pregnancy and is often continued throughout pregnancy for autoimmune conditions like lupus, as uncontrolled disease poses greater risks to mother and fetus. It crosses the placenta but is not associated with an increased risk of major birth defects.
Trimester-Specific Risks:
First Trimester:
No increased risk of major congenital malformations observed in studies.
Second Trimester:
Generally considered safe and often continued.
Third Trimester:
Generally considered safe and often continued.
Lactation
Hydroxychloroquine is excreted into breast milk in small amounts. It is generally considered compatible with breastfeeding, and the benefits of continued maternal therapy often outweigh the minimal risks to the infant. Monitor infant for adverse effects (e.g., rash, diarrhea).
Infant Risk:
Low risk (L2 - Safer drug).
Pediatric Use
Hydroxychloroquine is used in pediatric patients for juvenile idiopathic arthritis (JIA), systemic lupus erythematosus (SLE), and malaria. Dosing is weight-based. Long-term use requires careful ophthalmologic monitoring, similar to adults.
Geriatric Use
Use with caution in elderly patients due to potential for age-related decreases in renal and hepatic function, which may lead to increased drug accumulation and toxicity. Initiate at lower doses and monitor closely for adverse effects, especially visual changes and cardiac effects. Consider ideal body weight for dosing rather than actual body weight.
Clinical Information
Clinical Pearls
- Hydroxychloroquine has a very long half-life, meaning it takes a long time to reach steady state (several months) and a long time to be eliminated from the body. This contributes to its slow onset of action in rheumatic diseases.
- The most critical long-term side effect is retinopathy, which can be irreversible. Regular, comprehensive ophthalmologic screening is paramount, especially after 5 years of use or if risk factors are present.
- Dosing for chronic conditions should be based on ideal body weight (IBW) or actual body weight (ABW) if less than IBW, not exceeding 5 mg/kg/day (or 6.5 mg/kg/day for some guidelines) to minimize retinopathy risk.
- Take with food or milk to minimize gastrointestinal upset.
- Hydroxychloroquine is often considered a cornerstone therapy for SLE due to its efficacy in reducing flares, improving survival, and preventing organ damage.
- It has a relatively favorable safety profile compared to other DMARDs, making it a preferred first-line agent for many patients with lupus and mild RA.
Alternative Therapies
- For Rheumatoid Arthritis: Methotrexate, Sulfasalazine, Leflunomide, Biologic DMARDs (e.g., TNF inhibitors, IL-6 inhibitors, T-cell costimulation modulators)
- For Systemic Lupus Erythematosus: Belimumab, Anifrolumab, Mycophenolate mofetil, Azathioprine, Methotrexate, Corticosteroids
- For Malaria: Chloroquine (if susceptible), Mefloquine, Atovaquone/Proguanil, Doxycycline, Primaquine (for P. vivax/ovale radical cure)
Cost & Coverage
Average Cost:
$20 - $100 per 30 tablets (300mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (preferred generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about this medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.