Oseltamivir Side Effects


Oseltamivir (trade name Tamiflu), is a medication that’s been approved by the Food and Drug Administration for the treatment of influenza virus which causes seasonal flu. It is approved for adults and children age one year and older.

The typical adult dosage for flu is 75 mg, orally twice a day, for 5 days. For protection against influenza if you are or have been in close contact with someone who has the flu, a typical dose for an adult is 75 mg orally once a day for a minimum of 10 days.

To date, Oseltamivir is the most frequently prescribed flu medication. The manufacturer, Roche, believes that the first step in treating and preventing the flu is the use of Oseltamivir which must be taken within the first 48 hours of symptoms.

Tamiflu is available in capsule form and fruit flavored liquid form for dosages in younger children. It can be taken with or without food. At this time the medication has also been approved for flu prevention.(1,2)

Oseltamivir Pediatric Use

In 2009, the British Medical Journal reported that the medication may not be as safe in the treatment of children as previously thought. The recommendation was that the use of the medication be reserved for those who are in a high risk group where the virus would not typically cause severe symptoms.(3,4)

Nevertheless, as much as it may be enticing to use medication to decrease the effects of the influenza virus or to prevent the contraction of the flu, there have been some significant side effects from the medication reported in the literature which begs the answer to the question of risk versus benefit.

Oseltamivir is not intended to be used in place of getting a yearly flu shot and should not be used if you have had the flu vaccine nasally within the past two weeks.

Individuals who suffer lung disease, any condition causing swelling or any disorder of the brain or any other serious disease or health problem should also not use Oseltamivir. This medication is recognized as pregnancy category C., which means that it is unknown whether or not it is harmful to an unborn baby.(5)

Stevens Johnson Syndrome

In January 2010 the news media reported that a 19-year-old woman became blind after taking the medication, and reportedly did not have the flu. She was advised to take the medication by the National Health Services in Great Britain and within 72 hours was in the hospital on life support.

She suffered from Stevens Johnson syndrome and toxic epidermal necrolysis. Doctors have told her it could take up to two years for her to recover and they aren’t sure that her eyesight will return.(6)

Reported Side Effects of Oseltamivir

Patients who take the medication also report side effects such as:

• hallucinations
• hot flashes
• dry mouth
• nausea
• stomach pain
• dizziness
• fast heartbeat
• loss of memory
• delirium
• strange dreams
• night sweats
• lack of appetite
• cold sweats
• shaking
• buzzing in the body
• anxiety
• numbness and tingling in the hands, arms and feet
• extreme lack of energy

In fact, some individuals report that the side effects from the medication are worse than the disease it is supposed to treat.

A 2014 review study found a dose-response effect on psychiatric events. In trials of prevention in adults one person was harmed for every 94 treated. This included events such as nervousness, aggression, hallucinations, psychosis, suicide ideation and paranoia.8

However, neither the US FDA nor the European Medicines Agency found any psychiatric harms when they licensed oseltamivir.

A 2009 survey by the Health Protection Agency and the European Centre for Disease Prevention and Control found that out of 85 children treated with the drug 18% reported a neuropsychiatric side effect. They defined these events as one or more of the following symptoms: poor concentration or unable to think clearly, problems sleeping, feeling dazed or confused, bad dreams or nightmares, and behaving strangely.9

The manufacturer reports that the medication is only supposed to help an individual decrease the amount of time they are suffering symptoms by 24 hours.

In some cases, and considering the menu of potential side effects, it may be better to wait out the flu virus symptoms, providing the individual with good care, than it would be to take the medication and potentially experience side effects which are worse than the illness itself.

Oseltamivir Insurance Coverage

Oseltamivir is also expensive and not always covered by insurance companies. A full treatment of the 75 mg twice daily dose will cost about $110 – $120 for those paying out of pocket.

Many insurance plans classify it as a Tier 2 drug, which means a moderately high co-payment. The average co-pay for insured people is around $35. Most insurance companies, however, do cover Oseltamivir way way or another, including Medicare and Medicaid.

In August 2009 the news reported that the number of side effects being reported after the use of this medication had more than doubled, seemingly overnight. Most of the side effects included heart and psychiatric disorders.

These particular figures were published only days after a study was released which showed that more than half of the children who took the medication also suffered from nausea, nightmares and other reactions.(7)

Physicians in Great Britain have also learned that Oseltamivir may put a significant number of individuals at greater risk for a stroke when on the medication. It apparently is a combination of an interaction with warfarin, a blood thinning medication, which is taken by more than 600,000 people in Great Britain.

While there may be good reason to give the medication to individuals who have underlying medical conditions that place them at greater risk for developing serious complications from the flu, it appears that those same individuals are also at greater risk for developing serious side effects from the medication which would be used to treat the flu.


(1) Center for Disease Control and Prevention: 2011-2012 Influenza Antiviral Medications

(2) PubMed Health: Oseltamivir

(3) British Medical Journal Group Blog: Helen Macdonald on Side Effects, Tamiflu and the Swine Flu Hotline

(4) The Guardian: Don’t Give Tamiflu or Relenza to Under-12s, Warns Researchers

(5) Drugs.com: Tamiflu

(6) Health Freedom Alliance: Girl, 19, Lft Battling Blindness After Taking Tamiflu

(7) NHS Choices: Tamiflu Side Effects in Children

(8) Jefferson T, Jones MA, Doshi P, et al. (2014). “Neuraminidase inhibitors for preventing and treating influenza in healthy adults and children”. Cochrane Database Syst Rev 4: CD008965. doi:10.1002/14651858.CD008965.pub4. PMID 24718923.

(9) Cohen, D. (9 April 2014). “Oseltamivir: another case of regulatory failure?”. BMJ 348 (apr09 8): g2591–g2591. doi:10.1136/bmj.g2591.