Nirmatrelvir and ritonavir (Oral)
Generic name: nirmatrelvir and ritonavir [ nir-MA-trel-vir, rit-OH-na-vir ]
Drug class: Antiviral combinations
Medically reviewed by Drugs.com. Last updated on Jul 14, 2023.
Warning: Significant Drug Interactions with Nirmatrelvir/Ritonavir Kit
Nirmatrelvir/ritonavir kit includes ritonavir, a strong CYP3A inhibitor, which may lead to greater exposure of certain concomitant medications, resulting in potentially severe, life-threatening, or fatal events.
Prior to prescribing nirmatrelvir/ritonavir kit: 1) Review all medications taken by the patient to assess potential drug-drug interactions with a strong CYP3A inhibitor like nirmatrelvir/ritonavir kit and 2) Determine if concomitant medications require a dose adjustment, interruption, and/or additional monitoring.
Consider the benefit of nirmatrelvir/ritonavir kit treatment in reducing hospitalization and death, and whether the risk of potential drug-drug interactions for an individual patient can be appropriately managed .
Uses for nirmatrelvir and ritonavir
Nirmatrelvir and ritonavir combination is used to treat mild to moderate coronavirus disease 2019 (COVID-19) in non-hospitalized patients who are at high risk for progression to severe COVID-19 (eg, hospitalization, death).
This medicine is available only with your doctor's prescription.
Before using nirmatrelvir and ritonavir
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies have not been performed on the relationship of age to the effects of nirmatrelvir and ritonavir combination in children younger than 12 years of age or weighing less than 40 kilograms (kg). Safety and efficacy have not been established.
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of nirmatrelvir and ritonavir combination in the elderly.
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with Medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
- Ergoloid Mesylates
- Ethinyl Estradiol
- Isavuconazonium Sulfate
- St John's Wort
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Ado-Trastuzumab Emtansine
- Aripiprazole Lauroxil
- Arsenic Trioxide
- Dabigatran Etexilate
- Doxorubicin Hydrochloride Liposome
- Ethinyl Estradiol
- Fusidic Acid
- Inotuzumab Ozogamicin
- Irinotecan Liposome
- Isavuconazonium Sulfate
- Mirvetuximab Soravtansine-gynx
- Morphine Sulfate Liposome
- Sirolimus Protein-Bound
- Tenofovir Alafenamide
- Valproic Acid
- Vincristine Sulfate Liposome
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Tenofovir Disoproxil Fumarate
Interactions with Food/Tobacco/Alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other Medical Problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- HIV infection, uncontrolled or undiagnosed or
- Liver disease (eg, hepatitis)—Use with caution. May make these conditions worse.
- Kidney disease, moderate—Use with caution. A lower dose of nirmatrelvir may be needed for patients with this condition.
- Kidney disease, severe or
- Liver disease, severe—Use is not recommended in patients with these conditions.
Proper use of nirmatrelvir and ritonavir
Take this medicine exactly as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.
This medicine comes with a Fact Sheet for Patients, Parents, and Caregivers. Read and follow the information in the Fact Sheet carefully. Ask your doctor or pharmacist if you have any questions.
Take this medicine within 5 days of the onset of COVID-19 symptoms.
Swallow the tablet whole. Do not crush, break, or chew it. You may take this medicine with or without food.
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage form (tablets):
- For treatment of mild to moderate COVID-19:
- Adults and children 12 years of age and older weighing 40 kilograms (kg) or more—300 milligrams (mg) (2 tablets) of nirmatrelvir and 100 mg (1 tablet) of ritonavir taken as a single dose 2 times a day for 5 days.
- Children younger than 12 years of age or weighing less than 40 kg—Use and dose must be determined by your doctor.
- For treatment of mild to moderate COVID-19:
If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
If you miss a dose and it is within 8 hours of the time it is usually taken, take it as soon as possible, and then go back to your regular schedule. If you miss a dose and it is more than 8 hours, skip the missed dose and take your next dose at the regular time.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Precautions while using nirmatrelvir and ritonavir
It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.
You should not use this medicine together with alfuzosin (Uroxatral®), apalutamide (Erleada®), colchicine (Colcrys®), eletriptan (Relpax®), eplerenone (Inspra®), finerenone (Kerendia®), flibanserin (Addyi®), ivabradine (Corlanor®), lomitapide (Juxtapid®), lovastatin (Mevacor®), lumacaftor/ivacaftor (Orkambi®), lurasidone (Latuda®), midazolam (Versed®), naloxegol (Movantik®), pethidine (Demerol®), pimozide (Orap®), ranolazine (Ranexa®), rifampin (Rifadin®), sildenafil (Viagra®), silodosin (Rapaflo®), simvastatin (Zocor®), St John's wort, tolvaptan (Samsca®), triazolam (Halcion®), ubrogepant (Ubrelvy®), voclosporin (Lupkynis®), ergot medicine (eg, dihydroergotamine, ergotamine, methylergonovine, Ergomar®, Methergine®, Migranal®), medicine for heart rhythm problems (eg, amiodarone, dronedarone, flecainide, propafenone, quinidine, Cardioquin®, Multaq®, Pacerone®, Rythmol®, Tambocor®), or seizure medicine (eg, carbamazepine, phenobarbital, phenytoin, primidone, Dilantin®, Mysoline®, Solfoton®, Tegretol®).
Tell your doctor if you are pregnant or planning to become pregnant. Birth control pills may not work as well to prevent pregnancy when used with this medicine. Use another form of birth control (eg, condoms or spermicide) along with your pills.
This medicine may cause serious allergic reactions, including anaphylaxis, angioedema, which can be life-threatening and require immediate medical attention. Check with your doctor right away if you have chest tightness, cough, difficulty swallowing, dizziness, fast heartbeat, hives, itching, or skin rash, large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs, puffiness or swelling of the eyelids, or around the eyes, face, lips, or tongue, or unusual tiredness or weakness.
This medicine may cause serious skin reactions, including toxic epidermal necrolysis and Stevens-Johnson syndrome, which can be life-threatening and require immediate medical attention. Check with your doctor right away if you have blistering, peeling, or loosening of the skin, chills, cough, diarrhea, itching, joint or muscle pain, red irritated eyes, red skin lesions, often with a purple center, sore throat, sores, ulcers, or white spots in the mouth or on the lips, or unusual tiredness or weakness.
Check with your doctor right away if you have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, vomiting, or yellow eyes or skin. These could be symptoms of a serious liver problem.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
Side Effects of nirmatrelvir and ritonavir
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
- Blurred vision
- pounding in the ears
- slow or fast heartbeat
Incidence not known
- Blistering, peeling, or loosening of the skin
- chest tightness
- clay-colored stools
- dark urine
- difficulty swallowing
- fast heartbeat
- general tiredness or weakness
- hives, itching, or skin rash
- joint or muscle pain
- large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
- light-colored stools
- loss of appetite
- nausea and vomiting
- puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
- red irritated eyes
- red skin lesions, often with a purple center
- sore throat
- sores, ulcers, or white spots in the mouth or on the lips
- unpleasant breath odor
- unusual tiredness or weakness
- upper right abdominal or stomach pain
- vomiting of blood
- yellow eyes and skin
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- Change in taste
- loss of taste
- Difficulty in moving
- muscle aches, cramps, or stiffness
- swollen joints
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Frequently asked questions
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