How Effective is Tamiflu? What are the Risks of Tamiflu?
Influenza is the name of the virus that causes the flu. The flu usually means you have general body
aches and muscle aches. You have a fever, which can be very high, up to 104-105 or
it can be a low grade fever of 101-102. If you have a severe headache with a fever,
you need to go to the hospital or urgent care to be sure you do not have meningitis.
If it hurts to bend your head/neck, go to the hospital ER or urgent care for this reason
as well. If you are unable to keep liquids and solid foods in your stomach due to
vomiting, or if you feel faint or light headed, go to the ER/Urgent Care.
aches and muscle aches. You have a fever, which can be very high, up to 104-105 or
it can be a low grade fever of 101-102. If you have a severe headache with a fever,
you need to go to the hospital or urgent care to be sure you do not have meningitis.
If it hurts to bend your head/neck, go to the hospital ER or urgent care for this reason
as well. If you are unable to keep liquids and solid foods in your stomach due to
vomiting, or if you feel faint or light headed, go to the ER/Urgent Care.
The best way to avoid the flu is to avoid people who have the flu, and to wash your hands
before you touch your nose, mouth, and eyes, and to not allow anyone to sneeze on you.
Often this is impossible, especially if you are a mom or doctor.
Other than this, the influenza vaccine is the most effective means to prevent influenza,
but it does not provide complete protection even in those vaccinated. Sometimes, the vaccine is
ineffective due to antigentic mismatch between the virus de jour of the season
circulating in your area versus the virus antigents put in the vaccine.
before you touch your nose, mouth, and eyes, and to not allow anyone to sneeze on you.
Often this is impossible, especially if you are a mom or doctor.
Other than this, the influenza vaccine is the most effective means to prevent influenza,
but it does not provide complete protection even in those vaccinated. Sometimes, the vaccine is
ineffective due to antigentic mismatch between the virus de jour of the season
circulating in your area versus the virus antigents put in the vaccine.
Here is where Anti-Virals come in. There are also not 100% perfect but help in many
cases. Tamiflu, the best known among, them is not without risks. Read below for the
risks.**
cases. Tamiflu, the best known among, them is not without risks. Read below for the
risks.**
There are 2 types of Anti-Virals against Influenza
1. Adamantanes
2. Neuraminidase Inhibitors (NAI)s: Oseltamivir ==Tamiflu
1. Adamantanes: amantadine and rimantadine
target the viral M2 protein required for virus uncoating during replication.
2. Neuraminidase Inhibitors (NAI)s: Oseltamivir ==Tamiflu:
Is TamiFlu Safe?
WARNINGS AND PRECAUTIONS
Stevens Johnson Syndrome has been associated with Tamiflu (see Reference below).
INTRODUCTION
Tamiflu impairs the release of the virus from infected host (your) cells.
Resistance by these viruses to Tamiflu is still low but was reported to be widespread in
2009 treatment of seasonal influenza A viruses due to widespread viral resistance
2009 treatment of seasonal influenza A viruses due to widespread viral resistance
More recently, there have been reports of Oseltamivir-resistant H1N1pdm09 viruses.
NAI’s have limited effectiveness when given >48 hours after onset of symptoms.
NAI’s have limited effectiveness when given >48 hours after onset of symptoms.
The risks of an adverse effect are low, but if it does happen to your child, it is devastating and
life changing. I have not given Tamiflu to any of my kids but would take it likely myself
if I got the flu.
life changing. I have not given Tamiflu to any of my kids but would take it likely myself
if I got the flu.
**
The key reported risks of taking Tamiflu are:
1. Stevens-Johnson Syndrome: it is rare, but I have seen a couple of cases.
2. Optic Neuritis: rare. I have not seen a case of this yet.
References are below:
1.
• Serious skin/hypersensitivity reactions such as Stevens-Johnson Syndrome (a terrible,
life changing horrid syndrome), toxic epidermal necrolysis and erythema multiforme:
Discontinue TAMIFLU and initiate appropriate treatment if allergic-like reactions occur
or are suspected. (5.1) The risk of Stevens-Johnson Syndrome is very rare.
life changing horrid syndrome), toxic epidermal necrolysis and erythema multiforme:
Discontinue TAMIFLU and initiate appropriate treatment if allergic-like reactions occur
or are suspected. (5.1) The risk of Stevens-Johnson Syndrome is very rare.
Summary Statistics
Reports of TAMIFLU causing STEVENS-JOHNSON SYNDROME: 81
Reports of any side effect of TAMIFLU : 9602
Percentage of TAMIFLU patients where STEVENS-JOHNSON SYNDROME is a
reported side effect: 0.8436%
reported side effect: 0.8436%
FDA reports of any drug causing STEVENS-JOHNSON SYNDROME : 12918
Average percentage for all medicated patients where STEVENS-JOHNSON
SYNDROME is reported as a complication: 0.0810%
SYNDROME is reported as a complication: 0.0810%
See below for more information about Stevens Johnson Syndrome **
• Neuropsychiatric events: Patients with influenza, including those receiving TAMIFLU, particularly pediatric patients, may be at an increased risk of confusion or abnormal behavior.
Published online 2017 Jan 4. doi: 10.2147/IMCRJ.S113217
PMCID: PMC5221811
PMID: 28115874
Optic neuritis and acute anterior uveitis associated with influenza A infection: a case report
Abstract
Background
A few reports have described ocular complications of influenza A infection, such as impaired ocular movement, parasympathetic ocular nerve, keratitis, macular lesion, and frosted branch angiitis. We encountered a rare case of acute anterior uveitis and optic neuritis associated with influenza A infection.
Case presentation
A 70-year-old man presented with symptoms of upper respiratory tract infection. A rapid diagnostic test showed a positive result for influenza A. At the same time, he developed ocular symptoms including blurred vision with optic disk edema and hemorrhage in the left eye, and bilateral red eyes. Multiplex polymerase chain reaction performed on aqueous humor sample detected no viral infection. Visual field testing with a Goldmann perimeter showed central and paracentral scotomas in the left eye. In addition to antiviral agent (oseltamivir phosphate 75 mg), the patient was prescribed topical prednisolone acetate ophthalmic suspension eye drops every 5 hours and high-dose intravenous methylprednisolone 1,000 mg daily for 3 days. Two months later, his best-corrected visual acuity improved to 20/50 with regression of visual field defects in his left eye.
Conclusion
We report a case of bilateral acute anterior uveitis and unilateral optic neuritis concomitant with influenza A infection. Topical and systemic corticosteroids were effective to resolve acute anterior uveitis and neuritis. Analysis of aqueous humor sample suggested that acute anterior uveitis and optic neuritis in this case were not caused by influenza A virus infection per se but by autoimmune mechanism.
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How to Prescribe Tamiflu?
Tamiflu comes in the following:
Capsules: 30 mg, 45 mg, 75 mg
For little kids, it comes in an oral suspension:
360 mg oseltamivir base supplied as powder (constituted to a final concentration of 6
mg/mL)
mg/mL)
DOSAGE AND ADMINISTRATION
Treatment of influenza
• Adults and adolescents (13 years and older): 75 mg twice daily for 5 days
• Pediatric patients 1 to 12 years of age: Based on weight twice daily for 5 days: So for
a 3rd grader who weights about 65lbs, I would give (65/2.2=32kg ==x3mg/kg==>
90mg per day==>so I would give 45mg tablet 2x per day for 5 days or 15ml per day
of the oral suspension/liquid or 8ml in the am & 8ml in the pm.
a 3rd grader who weights about 65lbs, I would give (65/2.2=32kg ==x3mg/kg==>
90mg per day==>so I would give 45mg tablet 2x per day for 5 days or 15ml per day
of the oral suspension/liquid or 8ml in the am & 8ml in the pm.
• Pediatric patients 2 weeks to less than 1 year of age: 3mg/kg twice daily for 5 days
• Renally impaired adult patients (creatinine clearance >30-60 mL/min): Reduce to
30 mg twice daily for 5 days (2.4)
30 mg twice daily for 5 days (2.4)
• Renally impaired adult patients (creatinine clearance >10-30 mL/min): Reduce to
30 mg once daily for 5 days (2.4)
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. Treatment duration not to exceed 5 days (2.4)
every hemodialysis cycle. Treatment duration not to exceed 5 days (2.4)
• ESRD patients on CAPD: Reduce to a single 30 mg dose immediately (2.4)
Prophylaxis of influenza (2.3) • Adults and adolescents (13 years and older):
75 mg once daily for at least 10 days –
Prophylaxis of influenza (2.3) • Adults and adolescents (13 years and older):
75 mg once daily for at least 10 days –
Community outbreak: 75 mg once daily for up to 6 weeks
• Pediatric patients 1 to 12 years of age: Based on weight once daily for 10 days –
Community outbreak: Based on weight once daily for up to 6 weeks
Community outbreak: Based on weight once daily for up to 6 weeks
• Renally impaired adult patients (creatinine clearance >30-60 mL/min):
Reduce to 30 mg once daily (2.4)
Reduce to 30 mg once daily (2.4)
• Renally impaired adult patients (creatinine clearance >10-30 mL/min):
Reduce to 30 mg once every other day (2.4) • ESRD patients on hemodialysis: Reduce to 30 mg immediately and then 30 mg after alternate hemodialysis cycles for the recommended duration of prophylaxis (2.4)
Reduce to 30 mg once every other day (2.4) • ESRD patients on hemodialysis: Reduce to 30 mg immediately and then 30 mg after alternate hemodialysis cycles for the recommended duration of prophylaxis (2.4)
• ESRD patients on CAPD: Reduce to 30 mg immediately and then 30
Each patient needs to know the risks of taking Tamiflu.
The risks are low but can be very severe and permanent with terrible consequences
in the future.
The risks are low but can be very severe and permanent with terrible consequences
in the future.
Sandra Lora Cremers, MD, FACS
References:
2. . Pak J Med Sci. 2013 Nov-Dec; 29(6): 1450–1452.
PMCID: PMC3905385
Shama Parveen1 and M. Afzal Javed2
3.
3.
Br J Gen Pract. 2010 Feb 1; 60(571): 133–134.
PMCID: PMC2814276
Stevens–Johnson syndrome secondary to oseltamivir (Tamiflu®)
We write to highlight a serious cutaneous side effect of the drug oseltamivir or Tamiflu® which has recently been in widespread use due to the swine influenza epidemic.
A 17-year-old male presented to hospital with an erythematous rash over his limbs and trunk, oral ulceration, facial swelling, and blurred vision. He was well with no significant past medical history. Two weeks previously he had experienced a viral illness of headache, fever, and myalgia which was treated with oseltamivir (Tamiflu®) in the community. The day after completing the course he developed these symptoms. Other than paracetamol he had taken no other medication. Stevens–Johnson syndrome secondary to oseltamivir was diagnosed. He was found to have corneal ulceration requiring steroid eye drops and required admission and other supportive treatment before eventually recovering several weeks later.
Stevens–Johnson syndrome is a rare but recognised complication of oseltamivir (Tamiflu®) and the condition does have an associated mortality. To date there are no figures regarding adverse reactions of this nature, as most information comes from small previous studies.1 The most common events recorded are nausea and vomiting. A Cochrane Review showed that oseltamivir (Tamiflu®) slightly reduces time to alleviation of symptoms and is of use as post-exposure prophylaxis, but concludes low effectiveness.2There have been recent calls for caution in extensive use of this drug as these serious side effects become more apparent. Given the sometimes minimal benefits, it may be advisable to think twice before issuing a prescription; however, with increasing use, we are likely to see more cases of severe skin reactions in the future.
REFERENCES
1. Khazeni N, Bravata DM, Holty JE, et al. Safety and efficacy of extended-duration antiviral chemoprophylaxis against pandemic and seasonal influenza. Ann Intern Med. 2009;151(7):464–473.[PubMed]
2. Jefferson TO, Demicheli V, Di Pietrantonj C, et al. Neuraminidase inhibitors for preventing and treating influenza in healthy adults. Cochrane Database Syst Rev. 2006;3 CD001265. [PubMed]
Stevens–Johnson Syndrome (SJS), a dermatological emergency is a rare condition;
with a reported incidence of around 2.6 to 6.1 cases per million people per year with a
mortality rate of around 5%.1 SJS is named after two American pediatricians,
Albert Mason Stevens and Frank Chambliss Johnson, who jointly published the
first description of the disorder in the American Journal of Diseases of Children in
1922.
Stevens-Johnson Syndrome (SJS) is an immune-complex-mediated
hypersensitivity reaction that characteristically involves skin and mucous membrane.
The main known cause is hypersensitivity to certain drugs, followed by infections and,
rarely, cancers.3,4
with a reported incidence of around 2.6 to 6.1 cases per million people per year with a
mortality rate of around 5%.1 SJS is named after two American pediatricians,
Albert Mason Stevens and Frank Chambliss Johnson, who jointly published the
first description of the disorder in the American Journal of Diseases of Children in
1922.
Stevens-Johnson Syndrome (SJS) is an immune-complex-mediated
hypersensitivity reaction that characteristically involves skin and mucous membrane.
The main known cause is hypersensitivity to certain drugs, followed by infections and,
rarely, cancers.3,4
Although reported as a rare event Stevens–Johnson Syndrome (SJS) has been found to
be more common in adults than in children. Women are affected more often than men,
with cases occurring at a two to one (2:1) ratio. SJS is linked to a number of drugs,
infections & carcinomas; people with AIDS are also at an increased risk of developing
this disorder.1
be more common in adults than in children. Women are affected more often than men,
with cases occurring at a two to one (2:1) ratio. SJS is linked to a number of drugs,
infections & carcinomas; people with AIDS are also at an increased risk of developing
this disorder.1
SJS and toxic epidermal necrolysis (TEN) are two forms of this life-threatening skin
condition, in which cell death causes the epidermis to separate from the dermis.
Toxic Epidermal Necrolysis (TEN) is a more severe form of SJS and may be
associated with high morbidity and mortality. Toxic Epidermal Necrolysis (TEN)
can be classified by the extent of body surface area detachment as SJS –
A “minor form of TEN,” with less than 10% body surface area (BSA) detachment,
Overlapping SJS/TEN – Detachment of 10-30% BSA and TEN –
Detachment of more than 30% BSA.5
condition, in which cell death causes the epidermis to separate from the dermis.
Toxic Epidermal Necrolysis (TEN) is a more severe form of SJS and may be
associated with high morbidity and mortality. Toxic Epidermal Necrolysis (TEN)
can be classified by the extent of body surface area detachment as SJS –
A “minor form of TEN,” with less than 10% body surface area (BSA) detachment,
Overlapping SJS/TEN – Detachment of 10-30% BSA and TEN –
Detachment of more than 30% BSA.5
More recently, localised
clusters of oseltamivir-resistant H1N1pdm09 viruses have been detected [14, 15].
Aside from concerns regarding resistance, the effectiveness of the NAIs is limited when
Aside from concerns regarding resistance, the effectiveness of the NAIs is limited when
delivered >48 hours after the onset of symptoms.
More recently, localised clusters of oseltamivir-resistant H1N1pdm09 viruses have been detected [14, 15]. Aside from
concerns regarding resistance, the effectiveness of the NAIs is limited when delivered >48 hours
after the onset of symptoms.