Hydroxychloroquine interactions to avoid

Drug interactions | Food interactions | Other interactions | Avoiding interactions | When to see a doctor

Hydroxychloroquine is a prescription drug classified as an oral disease-modifying antirheumatic drug (DMARD), which most people commonly use for autoimmune diseases. Autoimmune diseases occur when your immune system is overactive to the point of causing damage to your organs or systems. The U.S. Food and Drug Administration (FDA) approves it for treating rheumatoid arthritis, systemic lupus erythematosus, and malaria. Hydroxychloroquine can prevent malaria and serve as prophylactic dosing. Hydroxychloroquine also received a surge in media presence as one of the many drugs used off-label in treating coronavirus after the pandemic that started in 2020. The FDA has not approved its use for this indication, and there are still ongoing clinical trials to determine its effectiveness and risk profile.

Hydroxychloroquine, often known as Plaquenil, is available as an oral tablet in strengths of 100 mg, 200 mg, 300 mg, and 400 mg. Hydroxychloroquine, as well as the related drug chloroquine, are derivatives of quinine. Hydroxychloroquine can interact with many other drugs as well as diseases. Hydroxychloroquine can cause a specific arrhythmia known as QT prolongation, and it should be avoided in use with other medications that have the same risk or a patient with a history of this type of arrhythmia. Patients with epilepsy (seizures) and are on medication for this condition should exercise caution when using hydroxychloroquine due to its potential to lower the seizure threshold. Other antirheumatic or immunosuppressant drugs should be avoided when possible or monitored closely. Drugs such as antacids or antibiotics can alter the bioavailability and absorption of hydroxychloroquine. Patients with a history of retinal disease, diabetes, or renal impairment (kidney disease) should exercise caution and speak to their prescriber before starting hydroxychloroquine. This is important because these interactions can worsen side effects or render one or both drugs ineffective.

Hydroxychloroquine drug interactions

Hydroxychloroquine can interact with other medications in various drug classes and certain conditions in the body. Its use is only appropriate for some. This is not intended to be an all-inclusive list of interactions, and you must speak to your prescriber and pharmacist about all comorbid conditions and other medications you are taking before starting hydroxychloroquine. This is intended to be informative but not used in place of medical advice from your healthcare professional.

Arrhythmogenic drugs

Hydroxychloroquine can cause life-threatening ventricular arrhythmias. It prolongs the QT interval, and these effects increase with increasing blood levels of hydroxychloroquine. Hydroxychloroquine is also linked to cardiotoxicity (heart damage) from inflammation, infiltration, or necrosis. There are a variety of drugs that also have these same risks or alter the heart’s rhythm, and combining hydroxychloroquine with these drugs increases the chance of a fatal arrhythmia from the combined effects of these drugs. These drugs are not just those intended to cause a change in the heart rhythm or treat arrhythmias, but also those intended to treat other conditions but cause a change in rhythm as an unintended consequence. Symptoms of an arrhythmia include heart palpitations, chest pain or tightening, dizziness, nausea, or loss of consciousness. Do not take hydroxychloroquine if you have a history of heart failure, irregular heart rate, or other heart problems. If you experience these symptoms while on hydroxychloroquine, seek medical help immediately. 

Examples: 

• Antiarrhythmics: Multaq (dronedarone), Pacerone (amiodarone), Tambocor (flecainide), Digitek (digoxin)
• Antipsychotics: Orap (pimozide), Mellaril (thioridazine), Abilify (aripiprazole), Clozaril (clozapine), Haldol (haloperidol), Seroquel (quetiapine)
• Antifungals: Nizoral (ketoconazole), Diflucan (fluconazole)
• Antidepressants: Prozac (fluoxetine), Celexa (citalopram), Lexapro (escitalopram)
• Antibiotics: Levaquin (levofloxacin), Floxin (ofloxacin), Cipro (ciprofloxacin), Avelox (moxifloxacin), Zithromax (azithromycin), Biaxin (clarithromycin)

Epilepsy or seizure drugs

Hydroxychloroquine is known to lower the seizure threshold and increase the likelihood of a seizure occurring. A seizure treatment regimen that had previously provided adequate seizure control may offer a different level of protection against seizures than their activity may be decreased. If hydroxychloroquine therapy is necessary, a dose adjustment may be warranted for seizure treatment medications. Seizures can have long-lasting effects by causing temporary or permanent injury to the person and limiting their ability to drive.

Examples: Briviact (brivaracetam), Tegretol (carbamazepine), Onfi (clobazam), Cerebyx (fosphenytoin), Neurontin (gabapentin), Dilantin (phenytoin)

Diabetic drugs

Hydroxychloroquine can cause an increase in serum insulin levels. When given insulin products or other antidiabetic medications, there is a chance that the blood glucose levels can be drastically lowered and cause hypoglycemia. Symptoms of low blood sugar include sweating, fatigue, lightheadedness, dizziness, and fainting. Patients may have to adjust the dosage of their insulin or blood glucose-lowering medications while taking hydroxychloroquine.

Examples:

• Insulins: Novolog (insulin aspart), Tresiba (insulin degludec), Lantus (insulin glargine), Humalog (insulin lispro)
• Incretin mimetics: Ozempic (semaglutide)
• Antidiabetic Drugs: Glucophage (metformin), Januvia (sitagliptin), Starlix (nateglinide), Actos (pioglitazone), Glucotrol (glipizide)

Mefloquine

Mefloquine is another antimalarial treatment. Mefloquine lowers the seizure threshold like hydroxychloroquine does. The use of these two drugs together drastically increases the risk of a seizure occurring. They should not be used together, especially in patients with a history of seizures or epilepsy.

Methotrexate

The concomitant use of hydroxychloroquine with methotrexate can lead to increased blood levels of methotrexate and methotrexate toxicity. Methotrexate toxicity can lead to nausea, vomiting, stomach ulcers, and renal failure. The use of these two drugs together should be avoided.

Cyclosporine

The concomitant use of hydroxychloroquine with cyclosporine can lead to increased blood levels. They may be used together cautiously, but cyclosporine levels should be monitored closely. Symptoms of elevated cyclosporine levels include nausea, vomiting, kidney damage, jaundice, and high blood pressure. 

Cimetidine

Cimetidine may cause hydroxychloroquine levels to double in the bloodstream when given together. The combination should be avoided as it can increase the risk of adverse effects such as permanent retinal damage, skin changes, hair loss, anemia, cardiac toxicities, and arrhythmias. 

Antacids 

Antacids change the pH level in your gastrointestinal system and can lead to a decrease in the absorption of hydroxychloroquine. This would render hydroxychloroquine less effective. It is recommended to allow at least 4 hours between administering antacids and hydroxychloroquine. 

Examples: Tums (calcium carbonate), Milk of Magnesia(magnesium hydroxide)

Hydroxychloroquine food interactions

While no documented food interactions exist for hydroxychloroquine, food is important in administering hydroxychloroquine. Taking hydroxychloroquine with food or milk is recommended to avoid an upset stomach after ingesting.

Other hydroxychloroquine interactions

Hydroxychloroquine can have serious side effects that are harmful in patients with certain other medical conditions. Hydroxychloroquine can be harmful to organs such as your heart, kidneys, skin, and eyes. If these organs have pre-existing diseases or risks, hydroxychloroquine may not be a safe choice.

Hydroxychloroquine and other diseases or conditions

There are a variety of conditions and comorbidities in which hydroxychloroquine use can be harmful. Patients with liver or kidney disease may not be the best candidates for hydroxychloroquine therapy. If you have a history of heart disease or arrhythmias, hydroxychloroquine could be dangerous to you. Hydroxychloroquine can cause irreversible retinal damage, and if you have a history of eye disease or vision problems, you should avoid hydroxychloroquine. If you have a history of an allergic reaction to hydroxychloroquine, chloroquine, or other related drug, you should not take hydroxychloroquine. 

Here is a list of health conditions for which you should refrain from or exercise utmost caution when considering taking hydroxychloroquine: 

• Ocular toxicity
• Porphyria
• Arrhythmias
• Bone Marrow suppression
• Ototoxicity
• Epilepsy or seizures
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency
• Hepatotoxicity
• Myasthenia gravis
• Psoriasis
• Diabetes mellitus
• Cardiac disease
• Renal impairment

How to minimize hydroxychloroquine interactions

Before starting hydroxychloroquine therapy, be sure your prescriber knows all your medications, including over-the-counter (OTC) medications and supplements. The best way to avoid an interaction is to be proactive. With hydroxychloroquine, you will also need to provide an accurate health history to properly assess any risk in taking this drug. While on this drug, make sure any new drugs you begin taking are checked against hydroxychloroquine by your pharmacist. Take hydroxychloroquine as prescribed and keep it stored at room temperature.

When to talk to a healthcare provider about hydroxychloroquine interactions

If you are experiencing one of the warning signs of an interaction with hydroxychloroquine, you should consult your prescriber immediately. Keep up with regular screenings of ocular and kidney functions. If you notice skin or vision changes, this could indicate an interaction or severe side effect. Seek help immediately if you notice any significant changes in how hydroxychloroquine works for you.