Paxlovid interactions to avoid

Drug interactions | Food interactions | Other interactions | How to minimize interactions | When to talk to a healthcare provider

Paxlovid is an oral antiviral medication developed to treat COVID-19. The drug, which consists of two active ingredients, nirmatrelvir and ritonavir, is prescribed for people with mild to moderate COVID-19 who are at high risk for severe disease. It helps block the virus’ ability to multiply or replicate itself, reducing the spread and number of viruses in the body.

Paxlovid can be a useful drug that can decrease the risk of hospitalization or death in high-risk individuals with COVID-19. However, it doesn’t come without the risk of drug interactions, which could decrease its effectiveness or cause harmful side effects. Several substances, including herbal products, may interact with Paxlovid. Therefore, taking precautions while taking Paxlovid is recommended, especially if you take other medications. 

Key takeaways

• Paxlovid is an FDA-approved drug for treating mild to moderate COVID-19 in high-risk individuals.
• Numerous potential drug interactions may affect Paxlovid‘s effectiveness or increase the risk of side effects. In addition, Paxlovid could increase the side effects of other drugs. 
• Several drugs may interact with Paxlovid, including heart medications, high blood pressure medications, antidepressants, blood thinners, seizure medications, immunosuppressants, and hormonal contraceptives. The severity of the drug interaction and its potential effects will depend on the specific drug taken. 
• Consult a healthcare provider to evaluate your risk of potential drug interactions and how to take Paxlovid safely and effectively. 

Paxlovid–drug interactions

Paxlovid, developed by Pfizer and granted initial Emergency Use Authorization and subsequent approval by the Food and Drug Administration (FDA) for COVID-19, is associated with several drug-drug interactions. Let’s explore the various drugs, including prescription and over-the-counter (OTC) medications, that can interact with Paxlovid. 

Statins

Paxlovid can interact with statins, a class of drugs commonly prescribed for managing high cholesterol levels. The ritonavir component of Paxlovid blocks certain enzymes that process statins, which can lead to increased blood levels of certain statins. Increased statin levels may cause increased side effects like muscle pain or weakness. Examples of statins that can interact with Paxlovid include:

• Zocor (simvastatin)
• Lipitor (atorvastatin)
• Mevacor (lovastatin)
• Crestor (rosuvastatin)

Simvastatin and lovastatin should not be taken at least 12 hours before the first Paxlovid dose, throughout treatment, and five days after completing Paxlovid. It’s also recommended to discontinue atorvastatin and rosuvastatin during treatment with Paxlovid. However, atorvastatin and rosuvastatin don’t typically need to be discontinued before or after Paxlovid treatment. 

Calcium channel blockers

Another interaction involves calcium channel blockers, which treat high blood pressure and chest pain. Paxlovid may increase the concentrations of these drugs, potentially leading to side effects like dangerously low blood pressure, dizziness, and fatigue. Some common calcium channel blockers include:

• Norvasc (amlodipine)
• Procardia (nifedipine)
• Cardizem (diltiazem)
• Calan (verapamil)

Calcium channel blockers often do not need to be discontinued while taking Paxlovid. However, a decrease in the dosage of the calcium channel blocker is usually recommended to avoid potential side effects. 

Anticoagulants and antiplatelet agents

Paxlovid may also interact with blood thinners, like anticoagulants and antiplatelet agents, which are used to prevent blood clots. Ritonavir can affect the metabolism of these drugs, potentially increasing their blood levels and the risk of bleeding complications. Examples of anticoagulant medications include:

• Coumadin (warfarin)
• Xarelto (rivaroxaban)
• Eliquis (apixaban)

Examples of antiplatelet agents include:

• Plavix (clopidogrel)
• Brilinta (ticagrelor)

Anticoagulants and antiplatelet agents should typically be avoided while taking Paxlovid due to the risk of bleeding. One thing to note is that Paxlovid may decrease the levels of clopidogrel, leading to an increased risk of blood clots. Depending on other factors, such as kidney function or the usual dose of the blood thinner, the dosage of the blood thinner may need to be adjusted. 

Antiarrhythmic drugs

Paxlovid can interact with certain antiarrhythmic drugs used to treat irregular heartbeats. The interaction may cause an increased risk of life-threatening heart rhythm problems. Examples of these antiarrhythmics include:

• Cordarone (amiodarone)
• Quinidex (quinidine)
• Lanoxin (digoxin)

In general, using antiarrhythmic drugs with Paxlovid is contraindicated, meaning they should not be taken together at all. 

Psychiatric medications

Certain psychiatric medications, such as antidepressants, antipsychotics, and benzodiazepines, may interact with Paxlovid. Taking a benzodiazepine, often prescribed for anxiety and sleep disorders, with Paxlovid may lead to increased blood levels of the benzodiazepine. This interaction may cause an increased risk of sedation and respiratory depression. Benzodiazepines include:

• Valium (diazepam)
• Versed (midazolam)
• Klonopin (clonazepam)
• Halcion (triazolam)

Certain antipsychotics, such as lurasidone and pimozide, should be avoided in combination with Paxlovid due to the risk of potentially dangerous heart rhythm problems. In some cases, the dosage of the antipsychotic drug may be reduced while taking Paxlovid. Antipsychotic medications that may interact with Paxlovid include:

• Clozaril (clozapine)
• Orap (pimozide)
• Latuda (lurasidone)
• Seroquel (quetiapine)

In addition, Paxlovid may increase the levels of the antidepressant trazodone, known under the brand name Desyrel. Increased levels of trazodone may lead to increased side effects, such as nausea, dizziness, and low blood pressure. The dosage of trazodone may need to be decreased while taking Paxlovid. 

Erectile dysfunction medications

Paxlovid can interact with medications used to treat erectile dysfunction (ED). The co-administration of Paxlovid may lead to elevated blood levels of these drugs, which can increase the risk of adverse effects like low blood pressure, a prolonged and painful erection (priapism), or vision changes. Some common erectile dysfunction medications include:

• Viagra (sildenafil)
• Cialis (tadalafil)
• Levitra (vardenafil)
• Stendra (avanafil)

These ED medications may need to be avoided while taking Paxlovid. However, in some cases, the dosage of these medications can be reduced while taking Paxlovid without increasing the risk of side effects. 

Migraine medications

A drug interaction is also possible with medications prescribed for migraine relief. Paxlovid could increase blood levels of these medications, potentially leading to increased side effects such as nausea, dizziness, or increased blood pressure. Examples of migraine medications include:

• Migranal (dihydroergotamine)
• Ergomar (ergotamine)
• Relpax (eletriptan)
• Ubrelvy (ubrogepant)

These medications should generally be avoided while taking Paxlovid. For example, taking ergot derivatives like dihydroergotamine and ergotamine with Paxlovid could lead to ergot toxicity and serious side effects. 

Hormonal contraceptives

Hormonal contraceptives like those containing ethinyl estradiol may interact with Paxlovid. This interaction can alter the contraceptive‘s effectiveness, leading to an increased risk of unintended pregnancy. Common hormonal contraceptives include:

• Medications like Yaz, Yasmin, and others that contain ethinyl estradiol

It’s recommended to use other forms of contraception, such as condoms, during treatment with Paxlovid. In addition, other contraceptives should be continued until one menstrual cycle after stopping Paxlovid. 

Immunosuppressants

Paxlovid may interact with immunosuppressants commonly used to prevent organ rejection after transplantation. Elevated blood levels of these drugs could increase risks of adverse events, such as kidney damage. Examples of these immunosuppressants include:

• Prograf (tacrolimus)
• Rapamune (sirolimus)
• Sandimmune (cyclosporine)
• Zortress (everolimus)

It’s generally recommended to avoid combining these immunosuppressants with Paxlovid due to the risk of increased side effects. However, cyclosporine or tacrolimus may be used with Paxlovid if the dosage is adjusted and side effects are monitored. 

Anticonvulsants

Certain anticonvulsants can also interact with Paxlovid, decreasing the levels of Paxlovid in the body. This interaction may lead to decreased effectiveness and potential viral resistance to Paxlovid. The anticonvulsants in question include:

• Luminal (phenobarbital)
• Dilantin (phenytoin)
• Tegretol (carbamazepine)

It’s recommended to avoid taking these anticonvulsants with Paxlovid. 

Individuals taking medications other than Paxlovid should consult their healthcare provider for possible dose adjustments or alternative medications when prescribed Paxlovid. 

Please note that this is a general guide and may not cover all the interactions of Paxlovid. Always consult your healthcare provider for medical advice.

Paxlovid-food interactions

According to the FDA label, Paxlovid can be taken with or without food. Eating a high-fat meal did not significantly affect the blood levels of nirmatrelvir. However, studies have shown that eating a meal may decrease the levels of ritonavir by around 20%, which could lead to decreased effectiveness of the drug. 

Paxlovid and grapefruit

Grapefruit and its juice are known inhibitors of certain enzymes in the liver. When Paxlovid is taken with grapefruit or grapefruit juice, the metabolic breakdown of Paxlovid can be disrupted. This interaction can lead to an increase in Paxlovid levels in the body, potentially leading to higher levels of the drug in the bloodstream and an increased risk of side effects. Therefore, it may be advised to avoid grapefruit juice while taking medicines like Paxlovid. 

Paxlovid and alcohol

It’s not known to what extent Paxlovid and alcohol interact. However, mixing both substances is not generally recommended due to the potential risk of side effects. Alcohol may also reduce the function of the immune system and potentially hinder the body’s ability to recover from illness. Limiting or avoiding alcohol is recommended to give the body the best chance to fight a viral infection like SARS-CoV-2. If alcohol is consumed, limiting it to moderate consumption may help reduce the risk of complications. 

Paxlovid and caffeine

There is limited research on Paxlovid and caffeine interactions. Consuming moderate amounts of caffeine, like a cup of coffee, is unlikely to cause significant issues for most people. However, in some cases, caffeine may affect how ritonavir is processed in the body, leading to higher levels of the antiviral medication. In addition, some people who have taken Paxlovid have reported a metallic taste in their mouths, making coffee less enjoyable.

Dietary recommendations

For people with or at risk of infection with the coronavirus, it may be beneficial to consider dietary recommendations. Maintaining a balanced diet rich in fruits, vegetables, whole grains, lean proteins, and healthy fats is recommended to support the immune system. Healthcare providers may also recommend staying well-hydrated by drinking water and avoiding excessive caffeine or sugar to maintain optimal health. 

Other Paxlovid interactions

Paxlovid may also interact with herbal or dietary supplements and other OTC medicines. Paxlovid may interact with other substances, including:

• St. John’s wort: Taking this herbal supplement with Paxlovid may lead to reduced blood levels of Paxlovid. As a result, St. John’s wort may decrease the effectiveness of Paxlovid. 
• CBD: While specific interactions between Paxlovid and CBD are not well-established, some experts suggest that CBD may affect the metabolism of certain medications. CBD can block certain enzymes that process medications, which could lead to increased concentrations and potential side effects. 
• Cough and cold medicines: These medicines should generally be safe to take with Paxlovid when taken as directed. However, some cough and cold medicines may contain dextromethorphan, a cough suppressant. Paxlovid may slightly increase the levels of dextromethorphan in the body and increase the risk of side effects. 

Consult your healthcare provider about any supplements or other substances you are taking before starting treatment with Paxlovid.

Other considerations

Drug interactions may need to be monitored, especially in people with certain conditions. These conditions include the following:

• Kidney disease: Dose adjustments and close monitoring may be needed for people with kidney disease. People with severe renal disease should not take Paxlovid due to the risk of increased levels and side effects of Paxlovid. 
• Uncontrolled or undiagnosed HIV infection: Paxlovid contains ritonavir, an antiviral medication used to treat HIV. However, the dosage of ritonavir in Paxlovid is not sufficient to treat HIV. The use of Paxlovid in someone with undiagnosed HIV infection could lead to HIV resistance, which may make the infection harder to treat. Individuals should know their HIV status and ensure that any existing HIV infection is appropriately managed before starting Paxlovid treatment.

How to minimize Paxlovid interactions

Minimizing the risk of drug interactions can help ensure the effectiveness of the medication and prevent possible adverse reactions. Let’s discuss how to minimize the risk of drug interactions with Paxlovid.

First and foremost, consulting a healthcare provider should be done before starting Paxlovid treatment. A healthcare provider can assess the potential risks and benefits of the medicine, especially if you’re taking other medications. You should keep a detailed list of all the medications you take, including:

• Prescription medications
• Over-the-counter drugs
• Herbal supplements
• Vitamins and minerals

A healthcare provider can adjust dosages, discontinue medications, and recommend alternatives if they determine there’s a risk for drug interactions. In addition, you may want to be aware of the potential warning signs of drug interactions. Some common warning signs may include:

• Unexpected side effects
• Changes in the effectiveness of a drug
• New symptoms or worsening of existing symptoms

When to talk to a healthcare provider about Paxlovid interactions

You should talk to a healthcare provider about Paxlovid interactions during the initial visit when they prescribe the medication. You can also consult your local pharmacist if you have concerns about drug interactions. 

In general, you should talk to healthcare providers about Paxlovid interaction if you:

• Take any prescription or over-the-counter medications
• Use any dietary supplements or herbal products
• Have any medical conditions or a history of certain illnesses
• Experience any unexpected side effects or changes in health

This is not a complete list of Paxlovid interactions. Discuss your overall medical history, including medical conditions and other medications you take, with your healthcare provider before starting treatment.