Article by Dalia Ghoniem For biomed Middle East
When the WHO declared H1N1 virus (swine flu ) as a pandemic, Tamiflu became the most known drug. A lot of rumors have arisen regarding Tamiflu ranging from it’s administration to it’s side effects.
So what are the facts about Tamiflu ?
Mechanism of action of Oseltamivir is suppression and decreasing the spread of influenza A and B viruses. It does this by blocking the action of neuraminidase, an enzyme produced by the viruses that enables them to be spread from infected cells to healthy cells. By preventing the spread of virus from cell to cell, the symptoms and duration of influenza infection are reduced.
On average, oseltamivir reduces the duration of symptoms by one and a half days if treatment is started within forty-eight hours of the beginning of symptoms. A huge advantage of Oseltamivir is that it was FDA approved in October 1999 as an antiviral medication.
But it also should be mentioned that Tamiflu is not a substitute for the flu shot; vaccination is still the first line of defense for flu protection. However, as it is known flu strains vary from area to area, so if you are exposed to a strain of the flu that is not the same strain as the one your vaccination protects against, you may still get the flu — and that’s where Tamiflu may be able to help. This means that Tamiflu can be used within 48 hours after the appearance of the symptoms and should not be taken as a prophylactic medication.
Although Tamiflu seems essential nowadays a lot of people are afraid of using it due to its side effects, of course not everyone taking the medication will suffer from side effects. Usual side effects are nausea, vomiting, diarrhea, bronchitis, abdominal pain, headache and dizziness. These side effects mainly occur due to oral administration of the medication and can be significantly reduced by taking the tablets after meals.
Unfortunately more serious side effects have occurred and they should be reported immediately, for example rare but serious skin reactions and allergic reactions have been reported. Some People, particularly children and adolescents, may be at an increased risk of self injury, confusion, seizures, panic attacks, delusions, delirium, depression, loss of consciousness, and even suicide shortly (24-48 hr) after taking Tamiflu. If any of these side effects appear Tamiflu should be stopped and a physician contacted immediately.
A lot of the schools are taking leaves due to the widespread of swine flu through them, so a lot of parents asking what should I do if my child got sick?!!! Should my child take antiviral medication or not??!!!!!
Although Tamiflu is supposed to be safe for children under 12 .The drugs were found to reduce the duration of the flu by a day, yet not to reduce the complications of the flu such as fewer asthma problems in children with existing asthma or the need to use antibiotics to treat secondary ear infections arising as part of the flu illness process. On the other hand, 1 in 20 children develop nausea and vomiting from these drugs which can cause life-threatening dehydration in any child.
It also should be pointed out that the FDA added a warning label to Tamiflu back in November of 2006, based on numerous reports of delirium and suicide in children. The FDA warning states “People with the flu, particularly children, may be at an increased risk of self-injury and confusion shortly after taking Tamiflu and should be closely monitored for signs of unusual behavior”
This data suggests that the benefit to risk ratio should be properly assessed in children on the basis of individual cases and according to the severity of the flu case.
A disturbing revelation nowadays is that the swine flu virus is becoming resistant to Tamiflu which is the most effective antiviral drugs for treatment. Flu viruses normally swap genes as part of their normal evolution; that means resistant viruses could quickly spread worldwide. But it is comforting that pandemic (Swine) flu is still largely vulnerable to the drug, unlike many seasonal flu viruses, which are now broadly resistant and more difficult to treat.
Studies inform us that as of November 2009, only 52 out of over 10,000 samples of 2009 swine flu tested worldwide have shown resistance to oseltamivir and World Health Organization (WHO) reported 57 cases of Tamiflu-resistant swine flu virus and additional cases are being investigated in the U.S. and U.K.
But regarding the seasonal flu, Tamiflu is not very effective in the 2008 seasonal H1N1 virus anymore due to acquired resistance in 99.6% of all 2008 seasonal H1N1 strains, up from 12% in 2007-2008 flu season, as declared by the CDC.
Finally we have to say that most people infected with flu virus will get well with rest and fluids. A hard-to-treat virus can be deadly for some patients, such as pregnant women or children with asthma or cerebral palsy, generally speaking patients who have weak immunity; these patients will need an effective treatment.
However the hopes are still high that Tamiflu will continue to be effective against the pandemic swine flu virus to prevent a worldwide disaster of further spread of the virus.