Oseltamivir 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 influenza (flu) caused by the influenza virus. It works by stopping the flu virus from spreading inside your body, which can help you feel better faster or prevent you from getting sick if you've been exposed.
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. If it causes stomach upset, taking it with food may help. Continue taking the medication as directed by your doctor or healthcare provider, even if you start feeling 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 if needed; discuss this option 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 portion after 35 days if stored in the refrigerator. If you choose to store the suspension at room temperature, discard any unused portion after 5 days. Keep all medications in a safe location, 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 almost time for your next dose (less than 2 hours), skip the missed dose and resume your regular 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. If it causes stomach upset, taking it with food may help. Continue taking the medication as directed by your doctor or healthcare provider, even if you start feeling 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 if needed; discuss this option 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 portion after 35 days if stored in the refrigerator. If you choose to store the suspension at room temperature, discard any unused portion after 5 days. Keep all medications in a safe location, 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 almost time for your next dose (less than 2 hours), skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses.
Lifestyle & Tips
- Start treatment as soon as possible, ideally within 48 hours of flu symptom onset, for best results.
- Take with food to help reduce stomach upset (nausea or vomiting).
- Complete the full course of medication, even if you start to feel better.
- Practice good hygiene (hand washing, covering coughs/sneezes) to prevent spread of flu.
- Get adequate rest and stay hydrated.
Available Forms & 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:
Influenza Treatment:
75 mg BID for 5 days, initiated within 48 hours of symptom onset.
Influenza Prophylaxis:
75 mg QD for 10 days following exposure, or up to 6 weeks during community outbreak.
Pediatric Dosing
Neonatal:
Treatment (term neonates <2 weeks): 3 mg/kg orally twice daily. Prophylaxis: Not established for neonates <1 year.
Infant:
Treatment (1-12 months): 3 mg/kg orally twice daily. Prophylaxis: Not established for infants <1 year.
Child:
Treatment (âĨ1 year, weight-based): 15 kg or less: 30 mg BID; >15 kg to 23 kg: 45 mg BID; >23 kg to 40 kg: 60 mg BID; >40 kg: 75 mg BID. All for 5 days. Prophylaxis (âĨ1 year, weight-based): Same doses once daily for 10 days.
Adolescent:
Treatment: 75 mg orally twice daily for 5 days. Prophylaxis: 75 mg orally once daily for 10 days.
Dose Adjustments
Renal Impairment:
Mild:
No adjustment needed (CrCl >60 mL/min).
Moderate:
Treatment (CrCl 30-60 mL/min): 30 mg orally twice daily for 5 days. Prophylaxis: 30 mg orally once daily.
Severe:
Treatment (CrCl 10-30 mL/min): 30 mg orally once daily for 5 days. Prophylaxis: 30 mg orally every other day. (CrCl <10 mL/min): Not recommended unless benefit outweighs risk.
Dialysis:
Hemodialysis: Treatment: 30 mg orally after every other hemodialysis cycle. Prophylaxis: 30 mg orally after every other hemodialysis cycle. Peritoneal Dialysis: Treatment: 30 mg orally once weekly. Prophylaxis: 30 mg orally once weekly.
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. Neuraminidase is a viral enzyme essential for viral replication, facilitating the release of new virions from infected cells and preventing the aggregation of virions. By inhibiting neuraminidase, oseltamivir carboxylate prevents the spread of the virus within the host.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 80% (of oseltamivir carboxylate from oseltamivir phosphate)
Tmax:
Oseltamivir phosphate: 0.65 hours; Oseltamivir carboxylate: 3-4 hours
FoodEffect:
Food does not significantly affect absorption, but administration with food can improve tolerability by reducing gastrointestinal upset.
Distribution:
Vd:
Oseltamivir carboxylate: 23-26 L
ProteinBinding:
Oseltamivir carboxylate: Approximately 3%
CnssPenetration:
Limited, but detectable levels in CSF (approximately 10-15% of plasma levels)
Elimination:
HalfLife:
Oseltamivir carboxylate: 6-10 hours
Clearance:
Oseltamivir carboxylate: 16.3 L/hour (renal clearance)
ExcretionRoute:
Primarily renal (glomerular filtration and tubular secretion) as oseltamivir carboxylate.
Unchanged:
<20% of dose excreted as oseltamivir phosphate; >90% of absorbed dose excreted as oseltamivir carboxylate.
Pharmacodynamics
OnsetOfAction:
Symptom improvement typically seen within 1-2 days if initiated early.
PeakEffect:
Peak plasma concentrations of active metabolite reached in 3-4 hours.
DurationOfAction:
Plasma half-life of 6-10 hours supports twice-daily 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
Nervous system problems, particularly in people with the flu, which can lead to death, especially in children. Be aware of:
+ Confusion
+ Changes in behavior
+ Speech problems
+ Shakiness
+ Seizures
+ Hallucinations
A severe skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis), which can cause long-term health problems and may be fatal. Seek help immediately if you experience:
+ 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
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns, don't hesitate to reach out to 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
Nervous system problems, particularly in people with the flu, which can lead to death, especially in children. Be aware of:
+ Confusion
+ Changes in behavior
+ Speech problems
+ Shakiness
+ Seizures
+ Hallucinations
A severe skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis), which can cause long-term health problems and may be fatal. Seek help immediately if you experience:
+ 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
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns, don't hesitate to reach out to 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:
- Severe allergic reactions (rash, itching/swelling, severe dizziness, trouble breathing)
- Sudden confusion, delirium, hallucinations, or unusual behavior (especially in children and adolescents)
- Self-injury or suicidal thoughts (rare, but reported)
- Worsening flu symptoms or development of new symptoms (e.g., difficulty breathing, chest pain)
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 allergic reaction you experienced, including any symptoms that occurred.
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 medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. They will help you determine if it is safe to take this medication in combination with your other medications and health conditions.
Remember, do not start, stop, or change the dose of any medication without first consulting your doctor to ensure your safety.
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 allergic reaction you experienced, including any symptoms that occurred.
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 medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. They will help you determine if it is safe to take this medication in combination with your other medications and health conditions.
Remember, do not start, stop, or change the dose of any medication without first consulting your doctor to ensure your safety.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
Note that this drug is not a substitute for a flu shot. If your doctor recommends a flu shot, it is crucial to get vaccinated as advised. This medication does not treat the common cold and will not prevent the spread of the flu to others.
Before receiving a flu vaccine, discuss with your doctor if you have recently taken this medication. Conversely, if you have just received a flu vaccine, consult with your doctor before starting this medication.
If you are pregnant, planning to become pregnant, or are breastfeeding, notify your doctor. You and your doctor will need to discuss the potential benefits and risks of this medication to both you and your baby.
Note that this drug is not a substitute for a flu shot. If your doctor recommends a flu shot, it is crucial to get vaccinated as advised. This medication does not treat the common cold and will not prevent the spread of the flu to others.
Before receiving a flu vaccine, discuss with your doctor if you have recently taken this medication. Conversely, if you have just received a flu vaccine, consult with your doctor before starting this medication.
If you are pregnant, planning to become pregnant, or are breastfeeding, notify your doctor. You and your doctor will need to discuss the potential benefits and risks of this medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Nausea
- Vomiting
- Diarrhea
- Abdominal pain
- Headache
- Dizziness
- In rare cases, seizures or altered mental status
What to Do:
Call 1-800-222-1222 (Poison Control Center) immediately or seek emergency medical attention. Treatment is supportive.
Drug Interactions
Moderate Interactions
- Probenecid (increases oseltamivir carboxylate exposure by ~2.5-fold via competition for renal tubular secretion; clinical significance generally minor, but may require monitoring in patients with renal impairment)
- Live Attenuated Influenza Vaccine (LAIV) (Oseltamivir may inhibit the replication of LAIV, reducing its effectiveness. Avoid administration of LAIV within 48 hours after oseltamivir, or administer oseltamivir at least 2 weeks after LAIV.)
Monitoring
Routine Monitoring
Resolution of influenza symptoms (fever, cough, body aches)
Frequency: Daily during treatment
Target: Symptom improvement/resolution
Action Threshold: Lack of improvement or worsening symptoms after 2-3 days of treatment may indicate resistance or alternative diagnosis; consider re-evaluation.
Renal function (CrCl)
Frequency: Prior to initiation and periodically during treatment in patients with known or suspected renal impairment
Target: Not applicable
Action Threshold: Adjust dose based on CrCl as per dosing guidelines.
Symptom Monitoring
- Nausea
- Vomiting
- Diarrhea
- Headache
- Neuropsychiatric events (e.g., delirium, hallucinations, abnormal behavior, self-injury, especially in pediatric patients)
Special Patient Groups
Pregnancy
Oseltamivir is generally recommended for pregnant women with confirmed or suspected influenza due to the increased risk of severe complications from influenza during pregnancy. Observational studies have not shown an increased risk of major birth defects or adverse pregnancy outcomes.
Trimester-Specific Risks:
First Trimester:
No increased risk of major birth defects observed in human studies.
Second Trimester:
No increased risk of adverse outcomes observed.
Third Trimester:
No increased risk of adverse outcomes observed.
Lactation
Oseltamivir and its active metabolite are excreted into breast milk in low amounts. The amount ingested by a breastfed infant is expected to be very low and unlikely to cause adverse effects. It is generally considered compatible with breastfeeding, and the benefits of treating the mother outweigh the potential risks to the infant.
Infant Risk:
Low risk
Pediatric Use
Oseltamivir is approved for treatment of influenza in patients 2 weeks of age and older, and for prophylaxis in patients 1 year of age and older. Dosing is weight-based. Close monitoring for neuropsychiatric events is recommended, especially in children and adolescents.
Geriatric Use
No specific dose adjustment is required based on age alone. However, geriatric patients are more likely to have decreased renal function, which may necessitate dose adjustment based on creatinine clearance. Monitor renal function.
Clinical Information
Clinical Pearls
- Oseltamivir is most effective when initiated within 48 hours of influenza symptom onset.
- It is effective against both influenza A and B viruses.
- Administer with food to minimize gastrointestinal side effects (nausea, vomiting).
- While rare, monitor patients, especially children and adolescents, for unusual behavior or neuropsychiatric symptoms.
- Resistance to oseltamivir can occur, but remains uncommon in circulating seasonal influenza strains.
- Consider for post-exposure prophylaxis in high-risk individuals or during outbreaks.
Alternative Therapies
- Zanamivir (Relenza) - inhaled neuraminidase inhibitor
- Peramivir (Rapivab) - intravenous neuraminidase inhibitor
- Baloxavir marboxil (Xofluza) - cap-dependent endonuclease inhibitor
Cost & Coverage
Average Cost:
$30 - $150 per 10 capsules (generic)
Generic Available:
Yes
Insurance Coverage:
Tier 1-3 (generic typically Tier 1-2, brand Tier 2-3)
General Drug Facts
If your symptoms or health issues persist or worsen, it is 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 it's a good idea to check with your pharmacist. If you have any questions or concerns about your 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 detailed information about the overdose, including the medication taken, the amount, and the time it occurred.