Rapivab (Peramivir): Single-Dose IV Flu Treatment, Dosage, and Side Effects

Medically reviewed by Alan Lucks | MD on August 28th, 2026 and Veronica Hackethal | MD, MSc on November 5th, 2026.

Published on March 8th, 2026.

Key Takeaways

Peramivir is a single-dose IV antiviral for flu in people 6 months and older.
It's given once, as a 15 to 30 minute IV infusion in a clinic or hospital, so it suits people who are severely ill or can't take pills.
Common side effects are mild, but serious reactions are possible. Always report unusual symptoms to your doctor.
This medication works best when started early in flu illness, ideally within 2 days of symptom onset.

What Is Rapivab (Peramivir)?

Peramivir, marketed as Rapivab in its brand form, is an antiviral medication belonging to a class of drugs called neuraminidase inhibitors. These drugs work by blocking an enzyme on the flu virus surface that allows it to spread to healthy cells. By stopping the virus from multiplying, peramivir helps your body fight off the influenza infection more effectively. It's one of 4 FDA-approved flu antivirals.

Peramivir is primarily used for patients with confirmed or suspected influenza who are unable to take inhaled or oral antiviral medications. This includes severely ill hospitalized patients, those on breathing machines, or individuals with conditions that prevent them from using other flu treatments. Most adults get a single 600 mg IV infusion over 15 to 30 minutes. Children and people with reduced kidney function get a lower dose. This information is educational and doesn't replace advice from your healthcare provider.

Who Gets Peramivir

Peramivir is for people 6 months and older who need flu treatment as a single IV dose. It's given in a clinic, emergency department, infusion center or hospital.

Because it has to be infused into a vein, peramivir can't be prescribed through telehealth. A healthcare professional gives it to you in person.

Most people treated for flu at home take an oral antiviral instead, usually oseltamivir or baloxavir. A licensed doctor can prescribe these online after a video visit.

Peramivir Dosage (Adults, Children, Kidney Function)

Group	Standard Dose	Adjusted Dose	Notes
Normal kidney function	600 mg IV	No adjustment needed	Single infusion, 15 to 30 minutes
Mild kidney impairment	600 mg IV	No adjustment needed	Monitor kidney function before treatment
CrCl 30-49 mL/min	600 mg IV	200 mg IV	Reduced dose based on creatinine clearance
CrCl 10-29 mL/min	600 mg IV	100 mg IV	Significant reduction; weigh risks vs. benefits
Hemodialysis	600 mg IV	100 mg IV	Give after dialysis session
Children 6 months and older	Weight-based single IV dose	Up to 600 mg	Single infusion, 15 to 30 minutes

Important: Peramivir is a prescription medication that must be administered by a healthcare professional, so you cannot take it at home. The medication is most effective when started within 48 hours of flu symptom onset. If you're hospitalized and receive peramivir, your medical team will monitor you during and after the infusion to watch for any reactions. Tell your care team about any kidney problems before the infusion, since your dose depends on kidney function. For dosing details by age and kidney function, see the peramivir dosage chart.

Side Effects

Peramivir is generally well-tolerated, meaning most people experience few problems when taking it. However, like all medications, it may cause side effects in some individuals. Understanding what to expect helps you recognize normal reactions versus symptoms that need medical attention. For a closer look at both mild and serious reactions, read our full guide to peramivir side effects.

Common Side Effects

Nausea and vomiting: Stomach upset is the most frequently reported side effect, typically mild and temporary.
Diarrhea: Loose stools may occur during or shortly after treatment; staying hydrated helps.
Headache: Mild to moderate head pain may develop, similar to tension or flu-related headaches.
Insomnia or sleep problems: Some patients report difficulty sleeping or restlessness during recovery.
Increased liver enzymes: Blood tests may show elevated liver function markers, which usually return to normal after treatment ends.
Low blood sugar (hypoglycemia): Usually mild; people with diabetes should check glucose levels closely.

Serious Side Effects

Allergic reactions: Rash, hives, difficulty breathing, or facial swelling may indicate a serious allergy requiring immediate treatment.
Neurological complications: Confusion, hallucinations, altered mental state, or unusual behavior can occur, particularly in high-risk patients.
Severe bleeding or bruising: Unexplained or excessive bleeding may signal a serious blood disorder.
Severe kidney problems: Kidney function may decline; patients with pre-existing kidney disease face higher risk.
Stevens-Johnson syndrome (SJS): A rare but serious skin reaction causing blistering and peeling; seek emergency care immediately if suspected.

When to Seek Medical Attention

Contact your healthcare provider right away if you develop fever, severe headache, confusion, difficulty breathing, unusual bruising, or signs of allergic reaction during or after peramivir treatment. While serious side effects are uncommon, catching them early makes a significant difference. If your symptoms feel life-threatening, call emergency services or go to the nearest emergency room. Don't wait to see if symptoms improve on their own.

Drug Interactions

Peramivir may interact with other medications, supplements, or substances you're taking. These interactions can reduce how well peramivir works or increase your risk of side effects. Inform your healthcare provider of all medications before receiving this drug. For more detailed information, review what to avoid when you're taking peramivir.

Live Flu Vaccine

Live attenuated influenza vaccine (LAIV) can be less effective if peramivir is given from 5 days before to 2 weeks after the vaccine; ask your doctor about timing or choose the flu shot.

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

NSAIDs like ibuprofen may increase kidney stress when combined with peramivir, particularly in patients with pre-existing kidney disease or dehydration.

Medications That Affect Kidney Function

Diuretics, ACE inhibitors, and other drugs affecting kidney function may reduce peramivir clearance and increase drug levels in your bloodstream.

Immunosuppressant Medications

Drugs that suppress your immune system (used for transplants or autoimmune conditions) may reduce your body's ability to fight off the flu virus while on peramivir.

Nephrotoxic Drugs

Medications toxic to the kidneys (such as aminoglycosides or amphotericin B) compound kidney injury risk when combined with peramivir.

Over-the-Counter Cold Remedies

Check labels on cold medicines; some contain ingredients that may interact or increase side effects when combined with peramivir.

Pros and Cons

Pros

Single-dose convenience: One intravenous infusion eliminates the need for multiple daily doses or oral medications.
Works for difficult cases: Suits people who are severely ill, can't swallow, or can't take other antivirals.
Fast action: Delivered directly into the bloodstream for rapid antiviral effect.
Well-studied safety profile: Used since 2014, with established safety data in hospitalized populations.

Cons

Must be given by IV in a healthcare setting: A healthcare professional gives it through an IV line, which some people find uncomfortable.
Limited effectiveness window: Must be started within 48 hours of symptom onset to be most effective.
Kidney function concerns: Patients with kidney disease need dose adjustments; may worsen kidney function in some cases.
Neurological side effects possible: Confusion or behavioral changes, though uncommon, can occur in hospitalized patients.

Frequently Asked Questions

Get answers to common questions about Rapivab (peramivir).

Peramivir is best suited for hospitalized patients, those on mechanical ventilation, or people who cannot take oral or inhaled antivirals. If you're severely ill with flu or unable to take other medications by mouth, your doctor may recommend peramivir's single-dose intravenous approach as the most practical option.

Peramivir begins working immediately when infused into your vein, as it enters the bloodstream directly. However, symptom improvement typically takes 2-5 days, similar to other flu antivirals. Starting treatment within 48 hours of symptom onset produces the best results.

Yes, but with caution and dose adjustments. If you have any kidney disease or reduced kidney function, inform your doctor before treatment. Your kidney function will be tested, and your dose will likely be reduced. Regular kidney function monitoring during treatment is important to catch any worsening early. Some drugs that affect kidney function can raise peramivir levels, so go over the list of peramivir interactions with your doctor.

Neurological symptoms like confusion, hallucinations, or unusual behavior are uncommon but possible, especially in hospitalized patients. If you or a family member notice these symptoms during or after peramivir treatment, report them to your medical team immediately. Some symptoms may be related to severe flu infection itself, while others may be drug-related, but all warrant medical evaluation.

No. Peramivir is given as an IV infusion in person, so it can't be prescribed through telehealth. For flu at home, you can get oral flu treatment online: a licensed doctor on Doctronic can prescribe an oral antiviral after a video visit.

Still have questions?

Ask Doctronic's medical AI for free, any hour, or talk to a licensed doctor by video.

The Bottom Line

Peramivir (Rapivab) is an effective antiviral medication that offers a practical single-dose option for people with serious influenza who can't take other flu treatments. Its intravenous delivery suits hospitalized patients, those on breathing support, or anyone unable to take oral medications. While side effects are usually mild, kidney function and neurological symptoms require monitoring. Starting treatment within 48 hours of flu symptom onset gives you the best chance at faster recovery. If you've been diagnosed with influenza and your doctor recommends peramivir, discuss any kidney concerns or medication allergies beforehand.

Treating flu at home? Ask Doctronic's medical AI for free, any hour, or see a licensed doctor by video in minutes for $39 to talk about oral antivirals.

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