Select a medication above to begin.
Paxlovid
nirmatrelvir and ritonavir
Black Box Warnings .
Significant Drug Interactions
ritonavir, a strong CYP3A inhibitor, may cause incr. exposure of certain medications, resulting in potential severe, life-threatening or fatal events; review all medications to assess potential drug interactions and determine if dose adjustment, interruption, or additional monitoring required; consider benefit of reduced hospitalization and death and risk of appropriate drug interaction management
Adult Dosing .
Dosage forms: TAB (5-day pack): nirmatrelvir 150 mg x20 and ritonavir 100 mg x10; TAB (moderate renal impairment 5-day pack): nirmatrelvir 150 mg x10 and ritonavir 100 mg x10; TAB (severe renal impairment 5-day pack): nirmatrelvir 150 mg x6 and ritonavir 100 mg x5
COVID-19, mild-moderate
- [1 dose PO bid x5 days]
- Start: ASAP within 5 days of symptom onset; Info: for patients at high risk for severe disease including hospitalization or death; 1 dose = 300 mg nirmatrelvir + 100 mg ritonavir; do not cut/crush/chew tab
renal dosing
- [see below]
- eGFR 30-59: nirmatrelvir 150 mg + ritonavir 100 mg bid; eGFR <30: nirmatrelvir 300 mg + ritonavir 100 mg x1, then nirmatrelvir 150 mg + ritonavir 100 mg qd x4 days
- HD: nirmatrelvir 300 mg + ritonavir 100 mg x1, then nirmatrelvir 150 mg + ritonavir 100 mg qd x4 days, on dialysis days administer after dialysis; no supplement; PD: not defined
hepatic dosing
- [see below]
- Child-Pugh Class A or B: no adjustment; Child-Pugh Class C: not defined
Peds Dosing .
- Dosage forms: TAB (5-day pack): nirmatrelvir 150 mg x20 and ritonavir 100 mg x10; TAB (moderate renal impairment 5-day pack): nirmatrelvir 150 mg x10 and ritonavir 100 mg x10; TAB (severe renal impairment 5-day pack): nirmatrelvir 150 mg x6 and ritonavir 100 mg x5
Special Note
- [FDA emergency use authorization (EUA)]
- Info: for mild-moderate COVID-19 in patients at high risk for severe disease including hospitalization or death; available from Pfizer Inc. or authorized distributors as directed by US government; for clinical trial eligibility and enrollment info, check www.clinicaltrials.gov
- [mandatory reporting for EUA]
- Info: serious medication errors and adverse events must be reported to FDA MedWatch (www.fda.gov/medwatch/report.htm or 1-800-FDA-1088) and Pfizer Inc. (1-800-438-1985)
COVID-19, mild-moderate
- [12 yo and older, >40 kg]
- Dose: 1 dose PO bid x5 days; Start: ASAP within 5 days of symptom onset; Info: for patients at high risk for severe disease including hospitalization or death; 1 dose = 300 mg nirmatrelvir + 100 mg ritonavir; do not cut/crush/chew tab
renal dosing
- [see below]
- eGFR 30-59: nirmatrelvir 150 mg + ritonavir 100 mg bid; eGFR <30: nirmatrelvir 300 mg + ritonavir 100 mg x1, then nirmatrelvir 150 mg + ritonavir 100 mg qd x4 days
- HD: nirmatrelvir 300 mg + ritonavir 100 mg x1, then nirmatrelvir 150 mg + ritonavir 100 mg qd x4 days, on dialysis days administer after dialysis; no supplement; PD: not defined
hepatic dosing
- [see below]
- Child-Pugh Class A or B: no adjustment; Child-Pugh Class C: not defined
Contraindications / Cautions .
- hypersensitivity to drug or ingredient
- caution: eGFR <60
- caution: hepatic disease
- caution: COVID-19 infection and untreated HIV infection, concurrent
Drug Interactions .
Overview
nirmatrelvir
SARS-CoV-2 main protease inhibitor
- CYP3A4 substrate
- patients on ritonavir- or cobicistat-containing HIV or HCV regimens may continue their tx as indicated
ritonavir
CYP3A4 booster; HIV protease inhibitor
- CYP3A4 substrate
- P-gp substrate
- CYP2D6 inhibitor, weak
- CYP3A4 inhibitor, strong
- BCRP inhibitor
- MRP2 inhibitor
- OATP1B1 inhibitor, moderate
- OATP1B3 inhibitor, moderate
- P-gp inhibitor, moderate
- CYP1A2 inducer, moderate
- CYP2B6 inducer, weak
- CYP2C8 inducer, weak
- CYP2C9 inducer, weak
- CYP2C19 inducer, weak
- CYP3A4 inducer, weak
- UGT1A1 inducer
- UGT1A4 inducer
- UGT1A9 inducer
- UGT2B4 inducer
- UGT2B7 inducer
- affected by altered fat absorption
- delays atrioventricular conduction
- hyperglycemic effects
- hyperuricemic effects
- interferes w/ gene therapy
Contraindicated
- alfuzosin
- amiodarone
- apalutamide
- butalbital
- carbamazepine
- cisapride
- colchicine
- conivaptan
- dihydroergotamine
- domperidone
- dronedarone
- elagolix
- eletriptan
- eliglustat
- encorafenib
- enzalutamide
- eplerenone
- finerenone
- flecainide
- flibanserin
- fosphenytoin
- gepirone
- grazoprevir
- ivabradine
- ivosidenib
- lumacaftor/ivacaftor
- lurasidone
- phenytoin
- pimozide
- propafenone
- quinidine (antiarrhythmic)
- ranolazine
- rifampin
- rifapentine
- sildenafil
- silodosin
- simvastatin
- St. John's wort
- suzetrigine
- thioridazine
- tolvaptan
- triazolam
- ubrogepant
- venetoclax
- voclosporin
- voriconazole
Avoid/Use Alternative
- acoramidis
- adagrasib
- ado-trastuzumab emtansine
- alfentanil
- avanafil
- avapritinib
- bedaquiline
- bendamustine
- betamethasone
- betibeglogene autotemcel
- bosentan
- bosutinib
- brigatinib
- deferasirox
- desogestrel (contraceptive)
- dexamethasone
- diazoxide
- dienogest (contraceptive)
- dihydrocodeine
- disopyramide
- docetaxel
- dordaviprone
- doxorubicin
- drospirenone (contraceptive)
- duvelisib
- efavirenz
- elacestrant
- elbasvir
- elinzanetant
- elivaldogene autotemcel
- lopinavir/ritonavir
- macitentan
- mobocertinib
- omaveloxolone
- prednisone
- rifabutin
- sunvozertinib
- tazemetostat
- topotecan
- toremifene
- trabectedin
- tramadol
- trazodone
- tretinoin
- triamcinolone
- vemurafenib
- vinblastine
- vorapaxar
- vorasidenib
- zavegepant
Monitor/Modify Tx
- acarbose
- acebutolol
- adenosine
- afatinib
- aficamten
- alectinib
- allopurinol
- alogliptin
- alprazolam
- aminophylline
- amitriptyline
- amlodipine
- amphetamine
- apraclonidine ophthalmic
- aripiprazole oral
- arsenic trioxide
- artemether/lumefantrine
- articaine
- asciminib
- atazanavir
- atenolol
- atogepant
- atorvastatin
- atovaquone
- avacopan
- avatrombopag
- betaxolol
- betaxolol ophthalmic
- bexagliflozin
- bisoprolol
- bortezomib
- brentuximab vedotin
- brexpiprazole
- bupivacaine
- bupivacaine liposomal
- buprenorphine
- butorphanol
- caffeine citrate
- canagliflozin
- carteolol ophthalmic
- carvedilol
- chloroprocaine
- cilostazol
- cinacalcet
- clonazepam
- clorazepate
- clozapine
- colesevelam
- cyclophosphamide
- darifenacin
- darunavir
- deflazacort
- desipramine
- dextroamphetamine
- erythromycin
- esmolol
- eszopiclone
- ethosuximide
- etripamil nasal
- etuvetidigene autotemcel
- exenatide
- febuxostat
- felodipine
- flurazepam
- fluvastatin
- fosamprenavir
- fostamatinib
- gadobenate dimeglumine
- galantamine
- glimepiride
- glipizide
- glyburide
- guanfacine
- haloperidol
- hydrocortisone
- ibrexafungerp
- ifosfamide
- iloperidone
- imatinib
- imipramine
- insulin
- istradefylline
- itraconazole
- lacosamide
- levobunolol ophthalmic
- levomilnacipran
- levothyroxine
- lidocaine
- linagliptin
- liothyronine
- liraglutide
- lixisenatide
- loperamide
- lumateperone
- maraviroc
- mavorixafor
- mepivacaine
- mexiletine
- midodrine
- miglitol
- nateglinide
- nebivolol
- nefazodone
- neostigmine
- nerandomilast
- nicardipine
- nifedipine
- nintedanib
- nortriptyline
- octreotide
- olanzapine
- omeprazole
- osilodrostat
- oxcarbazepine
- paclitaxel
- paltusotine
- paricalcitol
- paroxetine
- pasireotide
- pegloticase
- perphenazine
- pimavanserin
- pindolol
- pioglitazone
- polatuzumab vedotin
- pramlintide
- pravastatin
- praziquantel
- probenecid
- procainamide
- propofol
- propranolol
- pyridostigmine
- quinidine (CYP2D6 inhibitor)
- rasburicase
- regadenoson
- remifentanil
- remimazolam
- repaglinide
- revumenib
- rilpivirine
- riociguat
- risperidone
- rivastigmine
- romidepsin
- ropinirole
- ropivacaine
- rosiglitazone
- rosuvastatin
- saxagliptin
- semaglutide
- sertraline
- sitagliptin
- solifenacin
- sotalol
- stiripentol
- succinylcholine
- sugammadex
- tacrolimus
- talazoparib
- tenofovir alafenamide
- tenofovir disoproxil
- tezacaftor/ivacaftor
- thalidomide
- theophylline
- thyroid
- tiagabine
- timolol
- timolol ophthalmic
- tipranavir
- tirzepatide
- tofacitinib
- tolterodine
- upadacitinib
- valbenazine
- valproic acid
- valsartan
- vamorolone
- vanzacaftor/tezacaftor/deutivacaftor
- verapamil
- vilanterol inhaled
- vilazodone
- warfarin
- zanubrutinib
- ziftomenib
- zolpidem
- zuranolone
Caution Advised
- albendazole
- alosetron
- anagrelide
- armodafinil
- artesunate
- bazedoxifene
- belzutifan
- bexarotene
- bictegravir
- bupropion
- caffeine
- cannabis
- capmatinib
- carisoprodol
- chlordiazepoxide
- chlorpromazine
- clindamycin
- clobazam
- clomipramine
- cortisone
- cyclobenzaprine
- danshen
- darolutamide
- dicloxacillin
- doravirine
- doxazosin
- dronabinol
- duloxetine
- dutasteride
- echinacea
- elafibranor
- enasidenib
- entacapone
- eravacycline
- eslicarbazepine acetate
- esomeprazole
- estradiol (hormone replacement)
- estrogens, conjugated (hormone replacement)
- estrogens, esterified (hormone replacement)
- ethinyl estradiol (hormone replacement)
- felbamate
- fenfluramine
- fludrocortisone
- fluoxetine
- fluphenazine
- fluticasone furoate
- fruquintinib
- garlic
- gefitinib
- ginkgo
- ginseng, Asian
- glycerol phenylbutyrate
- griseofulvin
- hydromorphone
- isradipine
- lansoprazole
- lazertinib
- lenacapavir
- levonorgestrel intrauterine device (contraceptive)
- melatonin
- meropenem
- mirvetuximab soravtansine
- mometasone implant
- moxifloxacin
- mycophenolic acid
- naldemedine
- nelfinavir
- netupitant
- nevirapine
- odevixibat
- olutasidenib
- ospemifene
- oxybutynin
- pentoxifylline
- perampanel
- pimecrolimus topical
- pirfenidone
- pomalidomide
- prednisolone
- pretomanid
- raltegravir
- ramelteon
- riluzole
- ripretinib
- roflumilast topical
- rolapitant
- rufinamide
- samidorphan
- sarilumab
- seladelpar
- selexipag
- sirolimus topical
- sotagliflozin
- sulfasalazine
- tacrolimus topical
- tamoxifen
- tasimelteon
- tecovirimat
- telisotuzumab vedotin
- telotristat ethyl
- terbinafine
- tinidazole
- tisotumab vedotin
- tizanidine
- tocilizumab
- topiramate
- tovorafenib
- tradipitant
- trifluoperazine
- tucatinib
- turmeric
- vaborbactam
- venlafaxine
- vonoprazan
- voxilaprevir
- zaleplon
- zileuton
- zolmitriptan
Adverse Reactions .
Serious Reactions
- hypersensitivity reaction
- anaphylaxis
- Stevens-Johnson syndrome
- toxic epidermal necrolysis
- hepatotoxicity
- hepatitis
- jaundice
Common Reactions
- dysgeusia
- diarrhea
Safety/Monitoring .
Monitoring Parameters
no routine tests recommended
Pregnancy/Lactation .
Pregnancy
Clinical Summary
nirmatrelvir: weigh risk/benefit during pregnancy; inadequate human data available; possible risk of decr. fetal wt based on animal data at 10x recommended human dose
ritonavir: may use during pregnancy; no known risk of fetal harm based on human data
Lactation
Clinical Summary
weigh risk/benefit while breastfeeding; no human data available to assess risk of infant harm or effects on milk production
Pharmacology .
Metabolism: for nirmatrelvir: liver; CYP450: 3A4 substrate; for ritonavir: liver; CYP450: 2D6 (minor), 3A4 (major) substrate
Excretion: for nirmatrelvir: feces 49.6% (55% unchanged), urine 35.3% (27.5% unchanged); Half-life: 6.1h; for ritonavir: feces 86.4% (33.8% unchanged), urine 11.3% (3.5% unchanged); Half-life: 6.2h
Subclass: Coronavirus
Mechanism of Action
for nirmatrelvir: inhibits SARS-CoV-2 main protease (Mpro), preventing viral replication; for ritonavir: inhibits CYP3A, boosting nirmatrelvir levels
Formulary .
No Formulary Selected
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