What it's used for
Oseltamivir phosphate is used for the treatment of acute, uncomplicated influenza A and B in patients 2 weeks of age and older who have been symptomatic for no more than 48 hours, and for the prophylaxis of influenza in patients 1 year and older.
Source: U.S. FDA-approved prescribing information (openFDA).
Typical dosing
For adults and adolescents 13 years and older, the treatment dose is 75 mg twice daily for 5 days, while pediatric and renally impaired patients have weight- or kidney-function-based dosing adjustments.
Dosing shown here is the general FDA-labeled range. Your prescribing clinician determines the exact dose, form, and schedule for you — this is not a substitute for medical advice.
Common side effects
The most common adverse reactions in treatment studies include nausea, vomiting, and headache.
Covered strengths on the Tab $0 list
Covered at $0 with an active Tab membership when filled at a participating pharmacy nationwide or through mail order. A licensed clinician must prescribe the medication.
Related medications
Other antibiotics & antivirals medications covered at $0 with an active Tab membership.
Oseltamivir Phosphate cost without insurance
Cash prices for Oseltamivir Phosphate without insurance vary widely by pharmacy, strength and quantity — the same prescription can cost very different amounts at two pharmacies in the same town. That is the problem a membership solves.
Oseltamivir Phosphate is on Tab's covered $0 generic list. With an active Tab membership, every covered strength is $0 — not a percentage off, not a coupon that changes month to month — at participating pharmacies nationwide or through mail order. You do not need insurance, and Tab works whether or not you have a health plan.
Tab is a membership, not insurance. Covered medications require a prescription from a licensed clinician.
Oseltamivir Phosphate dosage and administration
Treatment of influenza Adults and adolescents (13 years and older): 75 mg twice daily for 5 days ( 2.2 ) Pediatric patients 1 to 12 years of age: Based on weight twice daily for 5 days ( 2.2 ) Pediatric patients 2 weeks to less than 1 year of age: 3mg/kg twice daily for 5 days ( 2.2 ) Renally impaired adult patients (creatinine clearance >30 to 60 mL/min): Reduce to 30 mg twice daily for 5 days ( 2.4 ) Renally impaired adult patients (creatinine clearance >10 to 30 mL/min): Reduce to 30 mg once daily for 5 days ( 2.4 ) ESRD patients on hemodialysis: Reduce to 30 mg immediately and then 30 mg after every hemodialysis cycle.
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Your prescribing clinician decides the exact dose, form and schedule for you — this is not medical advice.
Oseltamivir Phosphate side effects
The following serious adverse reactions are discussed below and elsewhere in the labeling: Serious skin and hypersensitivity reactions [see Warnings and Precautions (5.1) ] Neuropsychiatric events [see Warnings and Precautions (5.2) ] Most common adverse reactions (> 1% and more common than with placebo): Treatment studies – Nausea, vomiting, headache. ( 6.1 ) Prophylaxis studies – Nausea, vomiting, headache, pain. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Lannett Company, Inc.
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. This is not a complete list. Report side effects to your clinician, and seek care for anything severe or unexpected.
Oseltamivir Phosphate drug interactions
Live attenuated influenza vaccine (LAIV), intranasal: Avoid administration of LAIV within 2 weeks before or 48 hours after oseltamivir phosphate for oral suspension use, unless medically indicated. ( 7 ) 7.1 Influenza Vaccines Live Attenuated Influenza Vaccine The concurrent use of oseltamivir phosphate with live attenuated influenza vaccine (LAIV) intranasal has not been evaluated. However, because of the potential for oseltamivir phosphate to inhibit replication of live vaccine virus and possibly reduce the efficacy of LAIV, avoid administration of LAIV within 2 weeks before or 48 hours after oseltamivir phosphate administration, unless medically indicated. Inactivated Influenza Vaccine Inactivated influenza vaccine can be administered at any time relative to use of oseltamivir phosphate.
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Tell your clinician and pharmacist about every medication, supplement and over-the-counter product you take.
Who should not take oseltamivir phosphate
Oseltamivir phosphate for oral suspension is contraindicated in patients with known serious hypersensitivity to oseltamivir or any component of the product. Severe allergic reactions have included anaphylaxis and serious skin reactions including toxic epidermal necrolysis, Stevens-Johnson Syndrome, and erythema multiforme [see Warnings and Precautions (5.1) ] . Patients with known serious hypersensitivity to oseltamivir or any of the components of oseltamivir phosphate for oral suspension ( 4 )
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Whether this medication is appropriate for you is a clinical decision made by your prescribing clinician.
Common questions
Is oseltamivir Phosphate covered at $0 with Tab?
Yes. Oseltamivir Phosphate is on Tab's covered $0 generic list — every covered strength is $0 with an active membership, at participating pharmacies nationwide or by mail order.
Do I need insurance to get oseltamivir Phosphate through Tab?
No. Tab is a membership, not insurance. Covered medications are $0 with an active membership whether or not you have a health plan.
How do I get an oseltamivir Phosphate prescription with Tab?
Book a video visit with a licensed Tab clinician (unlimited visits are included with membership). If it's clinically appropriate, they send the prescription to your chosen participating pharmacy or by mail order.
How much does oseltamivir phosphate cost without insurance?
Without insurance, retail cash prices for oseltamivir phosphate vary by pharmacy, strength and quantity. Oseltamivir Phosphate is on Tab's covered $0 generic list, so every covered strength is $0 with an active Tab membership at participating pharmacies nationwide or by mail order.
What is the cheapest way to get oseltamivir phosphate?
For medications on Tab's covered list, a Tab membership is the cheapest route: covered strengths of oseltamivir phosphate are $0 with an active membership, and unlimited video visits with a licensed clinician are included, so the visit that produces the prescription is covered too.
What is the usual dose of oseltamivir phosphate?
Treatment of influenza Adults and adolescents (13 years and older): 75 mg twice daily for 5 days ( 2.2 ) Pediatric patients 1 to 12 years of age: Based on weight twice daily for 5 days ( 2.2 ) Pediatric patients 2 weeks to less than 1 year of age: 3mg/kg twice daily for 5 days ( 2.2 ) Renally impaired adult patients (creatinine clearance >30 to 60 mL/min): Reduce to 30 mg twice daily for 5 days ( 2.4 ) Renally impaired adult patients (creatinine clearance >10 to 30 mL/min): Reduce to 30 mg once daily for 5 days ( 2.4 ) ESRD patients on hemodialysis: Reduce to 30 mg immediately and then 30 mg after every hemodialysis cycle. (FDA-approved label, retrieved 2026-09-15. Your clinician sets your dose.)
What are the side effects of oseltamivir phosphate?
The following serious adverse reactions are discussed below and elsewhere in the labeling: Serious skin and hypersensitivity reactions [see Warnings and Precautions (5.1) ] Neuropsychiatric events [see Warnings and Precautions (5.2) ] Most common adverse reactions (> 1% and more common than with placebo): Treatment studies – Nausea, vomiting, headache. ( 6.1 ) Prophylaxis studies – Nausea, vomiting, headache, pain. (FDA-approved label, retrieved 2026-09-15.)
What interacts with oseltamivir phosphate?
Live attenuated influenza vaccine (LAIV), intranasal: Avoid administration of LAIV within 2 weeks before or 48 hours after oseltamivir phosphate for oral suspension use, unless medically indicated. ( 7 ) 7.1 Influenza Vaccines Live Attenuated Influenza Vaccine The concurrent use of oseltamivir phosphate with live attenuated influenza vaccine (LAIV) intranasal has not been evaluated. (FDA-approved label, retrieved 2026-09-15. Tell your clinician about every medication and supplement you take.)
Oseltamivir Phosphate is $0 on the covered list
Members pay $0 for covered generics at participating pharmacies nationwide or by mail order — plus unlimited virtual primary care, urgent care and dermatology visits. No insurance needed.
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