Long COVID Patterns in the RECOVER-Adult Study
November 21, 2025
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Brand Name :
Nafcil
(United States) [Available] ,Nallpen
(United States) [Available]Synonyms :
nafcillin
Class :
Class: Antimicrobials and Antiviral drugs; Sub class: Penicillins
Brand Name :
Nafcil
(United States) [Available] ,Nallpen
(United States) [Available]Synonyms :
nafcillin
Class :
Class: Antimicrobials and Antiviral drugs; Sub class: Penicillins
Dosage forms and strengths:
Tablet
800 mg
400 mg
Mild/moderate: A dose of 500mg IM given for every 4-6hrs or 500mg IV given for every 4hrs
Severe infections: A dose of 1 g IM or IV given every 4hrs
AHA recommends for native valve infective endocarditis (NVE) a dose of 2 g IV given for every 4hrs or else 3 g IV given for every 6hrs
AHA recommends for prosthetic valve endocarditis a dose of 2 g IV given for every 4hrs
The total dose per day is 12g
IDSA recommends a dose of 1.5-2 g IV given every 4-6hrs
IDSA recommends a dose of 9-12 g per day IV given and divided in every 4hrs
IDSA recommends a dose of 1.5-2 g IV given every 4-6hrs
The duration of treatment is recommended for 6 weeks
IDSA recommends for Incisional surgical site infections a dose of 2 g IV given for every 6hrs
IDSA recommends for MSSA skin/soft tissue infection a dose of 1-2 g IV given every 4hrs
IDSA recommends for streptococcal skin infections a dose of 1-2 g IV given every 4-6hrs
Dosage forms and strengths:
Tablet
25 mg
50 mg
Mild/Moderate: For neonates, a dose of 10 mg per kg IM given 2 times a day is recommended. For infants and children who are weighing < 40 kg recommends a dose of 25 mg per kg IM 2 times a day
For infants and children who are weighing > 40 kg recommends a dose of 500 mg IM every 4-6hrs hours a day
Severe: A dose of 1 g IM given every 4hrs a day
AHA Recommends for 1 year and above, a dose of 200 mg per kg per day given IV divided in every 4-6hrs
The total dose per day recommended is 12g
The duration of treatment is 4-6 weeks
IDSA Recommends for neonates 0-7 days a dose of 75 mg per kg per day IV given and divided in every 8-12hrs
IDSA Recommends for neonates 8-28 days a dose of 100-150 mg per kg per day IV divided every 6-8hrs
IDSA Recommends for infants and children a dose of 200 mg per kg per day given IV divided in every 6hrs
The total dose per day recommended is 12g
PDS and IDSA Recommends for infants and children 3 months and above, a dose of 150-200 mg per kg per day IV or IM given divided in every 6-8hrs
The total dose per day recommended is 12g
IDSA Recommends for 1month and above a dose of 50 mg per kg IV divided in every 6hrs a day
IDSA Recommends for MSSA Skin and soft tissue infection a dose of 100-150 mg per kg per day IV in 4 divided doses a day
Reffer Adult dosing
When naficillin combines with cariprazine, nafcillin will decrease the effect of action of cariprazine by affecting enzyme CYP3A4 metabolism.
When naficillin combines with cobimetinib, nafcillin will decrease the effect of action of cobimetinib by affecting enzyme CYP3A4 metabolism.
When naficillin combines with dienogest or estradiol valerate, nafcillin will decrease the effect of action of dienogest or estradiol valerate by affecting enzyme CYP3A4 metabolism.
When naficillin combines with doravirine, nafcillin will decrease the effect of action of doravirine by affecting enzyme CYP3A4 metabolism.
When naficillin combines with fostemsavir, nafcillin will decrease the effect of action of fostemsavir by affecting enzyme CYP3A4 metabolism.
When naficillin combines with isavuconazonium, nafcillin will decrease the effect of action of isavuconazonium by affecting enzyme CYP3A4 metabolism.
When naficillin combines with lonafarnib, nafcillin will decrease the effect of action of lonafarnib by affecting enzyme CYP3A4 metabolism.
When naficillin combines with lorlatinib, nafcillin will decrease the effect of action of lorlatinib by affecting enzyme CYP3A4 metabolism.
When nafcillin combines with lumacaftor/ivacaftor, nafcillin will decrease the effect of action of lumacaftor or ivacaftor by affecting enzyme CYP3A4 metabolism.
When nafcillin combines with lumefantrine, nafcillin will decrease the effect of action of lumefantrine by affecting enzyme CYP3A4 metabolism.
When nafcillin combines with naloxegol, nafcillin will decrease the effect of action of naloxegol by affecting enzyme CYP3A4 metabolism.
When nafcillin combines with panobinostat, nafcillin will decrease the effect of action of panobinostat by affecting enzyme CYP3A4 metabolism.
When nafcillin combines with praziquantel, nafcillin will decrease the effect of action of praziquantel by affecting enzyme CYP3A4 metabolism.
When nafcillin combines with regorafenib, nafcillin will decrease the effect of action of regorafenib by affecting enzyme CYP3A4 metabolism.
When nafcillin combines with roflumilast, nafcillin will decrease the effect of action of roflumilast by affecting enzyme CYP3A4 metabolism.
When nafcillin combines with vandetanib, nafcillin will decrease the effect of action of vandetanib by affecting enzyme CYP3A4 metabolism.
When nafcillin combines with abemaciclib, nafcillin will decrease the effect of action of abemaciclib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of alpelisib by synergism.
nafcillin will decrease the effect of action of apremilast by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of avapritinib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of axitinib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of BCG vaccine by antagonism.
nafcillin will decrease the effect of action of bedaquiline by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of bosutinib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of brigatinib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of cabozantinib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of calcitriol by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of capmatinib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of ceritinib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of cholera vaccine by antagonism.
nafcillin will decrease the effect of action of cobicistat by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of copanlisib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of daridorexant by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of deflazacort by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of demeclocycline by antagonism.
nafcillin will decrease the effect of action of doxycycline by antagonism.
nafcillin will decrease the effect of action of dronedarone by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of duvelisib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of elbasvir/grazoprevir by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of eliglustat by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of elvitegravir by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of encorafenib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of erdafitinib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of erythromycin ethylsuccinate by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of erythromycin lactobionate by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of erythromycin stearate by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of everolimus by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of fedratinib by affecting enzyme CYP3A4 metabolism.
nafcillin will increase the effect of action of fexinidazole by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of finerenone by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of ganaxolone by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of glasdegib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of ibrutinib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of idelalisib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of infigratinib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of irinotecan by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of istradefylline by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of ivabradine by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of ivacaftor by affecting enzyme CYP3A4 metabolism.
nafcillin or probenecid, both increase the levels of other action by decreasing renal clearance.
nafcillin will decrease the effect of action of ranolazine by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of selumetinib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of sildenafil by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of silodosin by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of simvastatin by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of tazemetostat by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of tepotinib by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of tetracycline by antagonism.
nafcillin will decrease the effect of action of typhoid vaccine by antagonism.
when both drugs are combined, there may be an increased level of serum concentration of alpelisib   
when both drugs are combined, there may be a reduced effect of abemaciclib by affecting hepatic or intestinal enzyme cyp3a4 metabolism  
nafcillin decreases the effect of ixazomib by altering intestinal/hepatic CYP3A4 enzyme metabolism
when both drugs are combined, there may be a reduced effect of nafcillin  
when both drugs are combined, there may be a decreased effect of nafcillin
tetracycline may decrease the therapeutic effects of penicillins by interfering with its bactericidal effects
tetracycline may decrease the therapeutic effects of penicillins by interfering with its bactericidal effects
nafcillin and asprin, both either increase the levels of others by plasma protein binding or by decreasing renal clearance.
nafcillin and asprin rectal, both either increase the levels of others by plasma protein binding or by decreasing renal clearance.
aspirin citric acid sodium bicarbonate
nafcillin and aspirin/citric acid/sodium bicarbonate, both either increase the levels of others by plasma protein binding or by decreasing renal clearance.
nafcillin will decrease the effect of action of atogepant by affecting enzyme CYP3A4 metabolism.
bazedoxifene conjugated estrogens
bazedoxifene/conjugated estrogens: nafcillin will decrease the effect of action of bazedoxifene/conjugated estrogens by affecting enzyme CYP3A4 metabolism or by altering intestinal flora.
nafcillin will decrease the effect of action of belumosudil by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of bendroflumethiazide by decreasing the renal clearance.
nafcillin will decrease the effect of action of cyclosporin by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of dantrolene by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of darifenacin by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of darunavir by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of diazepam by affecting enzyme CYP3A4 metabolism.
nafcillin will increase the levels of digoxin by altering the intestinal flora.
nafcillin will decrease the effect of action of diltiazem by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of erlotinib by affecting enzyme CYP3A4 metabolism
nafcillin will decrease the effect of action of escitalopram by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of estradiol by affecting enzyme CYP3A4 metabolism or by altering intestinal flora.
nafcillin will decrease the effect of action of tamoxifen by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of tamsulosin by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of temsirolimus by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of teniposide by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of terbinafine by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of tiagabine by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of ticagrelor by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of warfarin by affecting enzyme CYP3A4 metabolism.
nafcillin will decrease the effect of action of willow bark by decreasing renal clearance.
bismuth subcitrate, metronidazole and tetracycline
The interaction may depress the therapeutic efficacy of tetracyclines
The interaction may depress the therapeutic efficacy of tetracyclines
The interaction may depress the therapeutic efficacy of tetracyclines
The interaction may depress the therapeutic efficacy of tetracyclines
The interaction may depress the therapeutic efficacy of tetracyclines
penicillins may decrease the serum concentration of aminoglycosides.
penicillins may decrease the serum concentration of aminoglycosides.
penicillins may decrease the serum concentration of aminoglycosides.
penicillins may decrease the serum concentration of aminoglycosides.
penicillins may decrease the serum concentration of aminoglycosides.
When nafcillin is used together with clomocycline, this leads to a reduction in therapeutic effectiveness of nafcillin
Concomitant use of nafcillin and willow bark may result in increased levels of both drugs due to decreased renal clearance
when both drugs are combined, there may be an increased metabolism of paclitaxel 
when both drugs are combined, there may be a decreased level of serum concentration of erlotinib  
increases serum level of cabazitaxel by affecting the enzyme CYP3A4
nafcillin decreases the effect of gefitinib by altering the intestinal/ hepatic CYP3A4 enzyme metabolism
it increases the effect or level of palbociclib by altering the intestinal or hepatic CYP3A4 enzyme metabolism
penicillins may enhance the hypokalemic effect of dichlorphenamide
bismuth subcitrate, metronidazole and tetracycline
tetracyclines may diminish the therapeutic effect of penicillins
tetracyclines may diminish the therapeutic effect of penicillins
tetracyclines may diminish the therapeutic effect of penicillins
tetracyclines may diminish the therapeutic effect of penicillins
tetracyclines may diminish the therapeutic effect of penicillins
may have a decrease in excretion when combined with nafcillin
azithromycin decreases the effects of nafcillin by antagonism.
chlorothiazide increases the effects of nafcillin by decreasing the renal clearance.
nafcillin will decrease the effect of action of ondansetron by decreasing renal clearance.
nafcillin will decrease the effect of action of paclitaxel by decreasing renal clearance.
nafcillin will decrease the effect of action of vincristine liposomal by decreasing renal clearance.
nafcillin will decrease the effect of action of vinorelbine by decreasing renal clearance.
nafcillin will decrease the effect of action of ziprasidone by decreasing renal clearance.
Adverse drug reactions:Â
Frequency definedÂ
0.7-10%Â
HypersensitivityÂ
Allergic reactionsÂ
NeutropeniaÂ
Interstitial nephritisÂ
Possible hypokalemiaÂ
PainÂ
<1%Â
Neurotoxicity Â
Pseudomembranous colitisÂ
PhlebitisÂ
Frequency not definedÂ
laryngeal edemaÂ
LaryngospasmÂ
HypotensionÂ
AngioedemaÂ
SwellingÂ
InflammationÂ
PhlebitisÂ
ThrombophlebitisÂ
Black Box Warning Â
No specific warnings are available
Contraindication/Caution:Â
Contraindication:Â
Hypersensitivity Â
Caution:Â
AllergyÂ
Renal insufficiencyÂ
Hepatic insufficiencyÂ
Interstitial nephritisÂ
Renal tubular damageÂ
Pregnancy consideration:Â Â
Lactation:Â Â
Pregnancy category:Â Â
Category A: Studies that were well-controlled and met expectations revealed no risk to the fetus in either the first or second trimester.Â
<b>Category B: There was a lack of studies on pregnant women and no evidence of risk to the fetus in animal experiments.  Â
Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.   Â
Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.  Â
Category X: Drugs listed in this category outweigh the risks over benefits. Hence, these categories of drugs need to be avoided by pregnant women.   Â
Category N: There is no data available for the drug under this category
Pharmacology:Â
Nafcillin belongs to the peÂnicillin group of antibiotics. It is considered a narrow-spectrum,beÂta-lactamase-resistant penicillin.Â
Pharmacodynamics:Â
Nafcillin is an antibiotic made from 6-amino-peÂnicillanic acid. It works well against different typeÂs of Staphylococcus bacteria. This includes bacteria that make enzymes called peÂnicillinases. Penicillinases usually breÂak down other antibiotics. But Nafcillin resists these enzymes. So it can still fight the bacteÂria.Â
Pharmacokinetics:Â
AbsorptionÂ
Nafcillin doesn’t geÂt absorbed well when takeÂn by mouth.Â
DistributionÂ
It spreads widely in body fluids, bile, and boneÂs, even crossing the placeÂnta. Around 90% of Nafcillin in the bloodstream attaches to proteÂins.Â
MetabolismÂ
The liver breaks down most Nafcillin.Â
Elimination and excretionÂ
Nafcillin leÂaves the body mainly through the liveÂr, with 10-30% exiting via the kidneys. Its half-life lasts 33 to 61 minutes, showing its short-term effeÂcts in the body.Â
Administration:Â
Intravenous injeÂction should happen slowly – about 5 to 10 minutes. Intramuscular injections geÂt put deeply into large muscleÂs. If using IV drip, administer medication gradually for 30 to 60 minutes. DiffeÂrent methods guarantee the medicine works beÂst for the patient’s sickness. PropeÂr administration routes optimize medication deÂlivery and effectiveÂness.Â
Patient information leaflet
Generic Name: nafcillinÂ
Pronunciation: ba–kam-PIH-sil-inÂ
Why do we use nafcillin?Â
Nafcillin belongs to the family of penicillins. It fights infections from germs calleÂd Staphylococcus. These germs are tough because they make penicillinase. This enzyme breaks down other penicillins, but nafcillin reÂsists it. So doctors prescribe nafcillin when patieÂnts have infections from penicillinaseÂ-producing Staphylococcus strains. The antibiotic battles the bacteÂria successfully, making nafcillin a vital medicine.Â
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