Tamiflu 75mg Capsules
It is used to treat or prevent the flu. It may be given to you for other reasons. Talk with the doctor.
Drug Class
Antiviral
Pharmacologic Class
Neuraminidase Inhibitor
Pregnancy Category
Not available
FDA Approved
Oct 1999
DEA Schedule
Not Controlled
Overview
What is this medicine?
Oseltamivir is an antiviral medicine used to treat or prevent the flu (influenza). It works by stopping the flu virus from spreading in your body. It is most effective when started within 2 days of getting flu symptoms.
How to Use This Medicine
Taking Your Medication
To take this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food, but if it causes stomach upset, take it with food. Continue taking the medication as directed by your doctor or healthcare provider, even if you feel well.
If you have difficulty swallowing the medication, consult your doctor. In some cases, your doctor may advise you to mix the capsule contents with a sweet liquid, such as chocolate syrup, caramel topping, corn syrup, or light brown sugar dissolved in water. Alternatively, a liquid suspension can be prepared from the capsules, but you should discuss this with your doctor or pharmacist.
Storing and Disposing of Your Medication
Store the medication at room temperature in a dry place, avoiding bathrooms. If a liquid suspension is prepared from the capsules, store it in the refrigerator, but do not freeze. Discard any unused suspension after 35 days if stored in the refrigerator, or after 5 days if stored at room temperature. Keep all medications in a safe place, out of the reach of children and pets.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it is less than 2 hours until your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses.
To take this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food, but if it causes stomach upset, take it with food. Continue taking the medication as directed by your doctor or healthcare provider, even if you feel well.
If you have difficulty swallowing the medication, consult your doctor. In some cases, your doctor may advise you to mix the capsule contents with a sweet liquid, such as chocolate syrup, caramel topping, corn syrup, or light brown sugar dissolved in water. Alternatively, a liquid suspension can be prepared from the capsules, but you should discuss this with your doctor or pharmacist.
Storing and Disposing of Your Medication
Store the medication at room temperature in a dry place, avoiding bathrooms. If a liquid suspension is prepared from the capsules, store it in the refrigerator, but do not freeze. Discard any unused suspension after 35 days if stored in the refrigerator, or after 5 days if stored at room temperature. Keep all medications in a safe place, out of the reach of children and pets.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it is less than 2 hours until your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses.
Lifestyle & Tips
- Take with food to reduce stomach upset.
- Complete the full course of medication, even if you start feeling better.
- Oseltamivir is not a substitute for the annual flu vaccine.
- Practice good hand hygiene and avoid close contact with sick individuals to prevent flu spread.
Available Forms & Alternatives
Available Strengths:
Generic Alternatives:
Dosing & Administration
Adult Dosing
Standard Dose:
Treatment: 75 mg orally twice daily for 5 days. Prophylaxis: 75 mg orally once daily for 10 days (or up to 6 weeks during community outbreak).
Dose Range:
75 - 75 mg
Condition-Specific Dosing:
treatment:
Initiate within 48 hours of symptom onset.
prophylaxis:
Initiate within 48 hours of exposure.
Pediatric Dosing
Neonatal:
Treatment (full-term infants >2 weeks to <1 year): Weight-based dosing (e.g., 3 mg/kg twice daily). Prophylaxis: Not routinely recommended for infants <1 year.
Infant:
Treatment (1 to <12 months): Weight-based dosing (e.g., 3 mg/kg twice daily). Prophylaxis: Not routinely recommended for infants <1 year.
Child:
Treatment (1 to 12 years, >40 kg): 75 mg twice daily. Prophylaxis (1 to 12 years, >40 kg): 75 mg once daily. Lower weights use weight-based dosing (e.g., 30 mg, 45 mg, 60 mg twice daily for treatment based on weight band).
Adolescent:
Treatment (>13 years): 75 mg twice daily for 5 days. Prophylaxis (>13 years): 75 mg once daily for 10 days.
Dose Adjustments
Renal Impairment:
Mild:
No adjustment needed (CrCl >60 mL/min).
Moderate:
Treatment: 30 mg once daily. Prophylaxis: 30 mg every other day (CrCl 30-60 mL/min).
Severe:
Treatment: 30 mg once daily. Prophylaxis: 30 mg every other day (CrCl 10-30 mL/min).
Dialysis:
Hemodialysis: Treatment: 30 mg after each hemodialysis cycle. Prophylaxis: 30 mg after every other hemodialysis cycle. Peritoneal Dialysis: Treatment: 30 mg once, then 30 mg once weekly. Prophylaxis: 30 mg once every 7 days.
Hepatic Impairment:
Mild:
No adjustment.
Moderate:
No adjustment.
Severe:
No adjustment.
Pharmacology
Mechanism of Action
Oseltamivir is a prodrug that is hydrolyzed to oseltamivir carboxylate, an active metabolite. Oseltamivir carboxylate is a potent and selective inhibitor of influenza A and B virus neuraminidase enzymes. Neuraminidase is a viral enzyme that is essential for viral replication, release of new virions from infected cells, and further spread of the virus within the respiratory tract. By inhibiting neuraminidase, oseltamivir prevents the release of new viral particles, thereby reducing viral spread and disease severity.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 80% (of oseltamivir carboxylate)
Tmax:
Oseltamivir: 0.5-1 hour; Oseltamivir carboxylate: 3-4 hours
FoodEffect:
Minimal effect on bioavailability; taking with food may improve tolerability (reduce GI upset).
Distribution:
Vd:
Oseltamivir carboxylate: 23-26 L
ProteinBinding:
Oseltamivir carboxylate: <3%
CnssPenetration:
Limited, but detectable levels in CSF (approximately 10-30% of plasma levels).
Elimination:
HalfLife:
Oseltamivir: 1-3 hours; Oseltamivir carboxylate: 6-10 hours
Clearance:
Primarily renal clearance of oseltamivir carboxylate.
ExcretionRoute:
Renal (glomerular filtration and tubular secretion)
Unchanged:
Oseltamivir: <20% (excreted as unchanged drug); Oseltamivir carboxylate: >90% (excreted as unchanged active metabolite).
Pharmacodynamics
OnsetOfAction:
Rapid (within hours of first dose)
PeakEffect:
Within 3-4 hours (peak plasma concentration of active metabolite)
DurationOfAction:
Approximately 12 hours (supports BID dosing)
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Neurological problems, particularly if you have the flu, which can lead to death, especially in children. Seek help if you experience:
+ Confusion
+ Changes in behavior
+ Speech problems
+ Shakiness
+ Seizures
+ Hallucinations
A severe skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis), which can cause serious health issues and even death. Get medical help right away if you notice:
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Red or irritated eyes
+ Sores in your mouth, throat, nose, or eyes
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. Contact your doctor or seek medical help if you experience:
Diarrhea
Upset stomach
Vomiting
* Headache
These are not all the possible side effects that may occur. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Neurological problems, particularly if you have the flu, which can lead to death, especially in children. Seek help if you experience:
+ Confusion
+ Changes in behavior
+ Speech problems
+ Shakiness
+ Seizures
+ Hallucinations
A severe skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis), which can cause serious health issues and even death. Get medical help right away if you notice:
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Red or irritated eyes
+ Sores in your mouth, throat, nose, or eyes
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. Contact your doctor or seek medical help if you experience:
Diarrhea
Upset stomach
Vomiting
* Headache
These are not all the possible side effects that may occur. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Worsening flu symptoms
- Difficulty breathing
- Chest pain
- Confusion
- Severe vomiting or diarrhea
- Signs of unusual behavior, delirium, or hallucinations (especially in children and adolescents)
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced as a result of the allergy.
If you have kidney disease, as this may affect your ability to take this medication.
This list is not exhaustive, and it is crucial to discuss all your health conditions and medications with your doctor. Please provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
* Your complete medical history, including any health problems you are experiencing
Before starting, stopping, or changing the dose of any medication, including this one, you must consult with your doctor to ensure your safety. It is vital to verify that it is safe to take this medication in combination with all your other medications and health conditions.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced as a result of the allergy.
If you have kidney disease, as this may affect your ability to take this medication.
This list is not exhaustive, and it is crucial to discuss all your health conditions and medications with your doctor. Please provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
* Your complete medical history, including any health problems you are experiencing
Before starting, stopping, or changing the dose of any medication, including this one, you must consult with your doctor to ensure your safety. It is vital to verify that it is safe to take this medication in combination with all your other medications and health conditions.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
This medication is not a substitute for a flu shot. If your doctor has recommended that you receive a flu shot, it is crucial that you follow their advice and get vaccinated. This medication is specifically designed to treat the flu, not the common cold.
Additionally, taking this medication will not prevent you from spreading the flu to others.
If you are considering getting a flu vaccine, it is important to discuss the timing with your doctor, both before taking this medication and after completing your treatment.
Before starting this medication, you should also inform your doctor if you are pregnant, planning to become pregnant, or are breastfeeding. This will allow you to have a thorough discussion about the potential benefits and risks of the medication to both you and your baby.
This medication is not a substitute for a flu shot. If your doctor has recommended that you receive a flu shot, it is crucial that you follow their advice and get vaccinated. This medication is specifically designed to treat the flu, not the common cold.
Additionally, taking this medication will not prevent you from spreading the flu to others.
If you are considering getting a flu vaccine, it is important to discuss the timing with your doctor, both before taking this medication and after completing your treatment.
Before starting this medication, you should also inform your doctor if you are pregnant, planning to become pregnant, or are breastfeeding. This will allow you to have a thorough discussion about the potential benefits and risks of the medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Nausea
- Vomiting
- Diarrhea
- Abdominal pain
- Headache
- Tremor
- Seizures (rare)
What to Do:
Call 1-800-222-1222 (Poison Control) or seek immediate medical attention. Treatment is supportive.
Drug Interactions
Moderate Interactions
- Probenecid
- Live attenuated influenza vaccine (LAIV)
Monitoring
Routine Monitoring
Influenza symptoms (e.g., fever, cough, sore throat, body aches)
Frequency: Daily during treatment
Target: Resolution or improvement of symptoms
Action Threshold: Lack of improvement or worsening symptoms after 2-3 days of treatment may indicate treatment failure, resistance, or alternative diagnosis. Seek medical attention.
Renal function (CrCl)
Frequency: Prior to initiation and periodically during treatment for patients with known or suspected renal impairment.
Target: Not applicable (used for dose adjustment)
Action Threshold: CrCl <60 mL/min requires dose adjustment.
Symptom Monitoring
- Fever
- Cough
- Sore throat
- Body aches
- Headache
- Fatigue
- Nausea
- Vomiting
- Unusual behavior (especially in pediatric patients)
Special Patient Groups
Pregnancy
Oseltamivir is generally considered acceptable for use during pregnancy when the potential benefits outweigh the risks, especially given the risks of severe influenza in pregnant women. Data from observational studies and registries have not shown an increased risk of major birth defects or adverse pregnancy outcomes.
Trimester-Specific Risks:
First Trimester:
Limited data, but no clear evidence of increased risk.
Second Trimester:
More data available, no increased risk observed.
Third Trimester:
More data available, no increased risk observed.
Lactation
Oseltamivir and its active metabolite are excreted into breast milk in low amounts. The amount ingested by a breastfed infant is generally considered to be subtherapeutic. The benefits of breastfeeding and the mother's need for the drug should be weighed against any potential risk to the infant. Generally considered compatible with breastfeeding.
Infant Risk:
Low risk; monitor for gastrointestinal upset (e.g., diarrhea, vomiting) or rash.
Pediatric Use
Approved for treatment of influenza in full-term infants >2 weeks of age and for prophylaxis in individuals >1 year of age. Dosing is weight-based for younger children. Close monitoring for neuropsychiatric events is recommended.
Geriatric Use
No specific dose adjustment is required based on age alone. However, elderly patients are more likely to have age-related decreases in renal function, which may necessitate dose adjustment based on creatinine clearance.
Clinical Information
Clinical Pearls
- Oseltamivir is most effective when initiated within 48 hours of influenza symptom onset for treatment.
- For prophylaxis, it should be started within 48 hours of exposure to an infected individual.
- It is not a substitute for the annual influenza vaccine.
- Patients should be advised to complete the full course of therapy, even if symptoms improve.
- Monitor for neuropsychiatric events, especially in pediatric patients, and advise caregivers to seek medical attention if such symptoms occur.
Alternative Therapies
- Zanamivir (Relenza) - inhaled neuraminidase inhibitor
- Baloxavir marboxil (Xofluza) - cap-dependent endonuclease inhibitor
- Peramivir (Rapivab) - IV neuraminidase inhibitor
Cost & Coverage
Average Cost:
Varies widely, typically $100-$200 per 10 capsules (75mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (generic), Tier 3 (brand)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about this medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the medication, including the amount taken and the time it happened, to facilitate prompt and effective treatment.