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Tamiflu Side Effects

Please note - some side effects for Tamiflu may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).


Side Effects of Tamiflu - for the Consumer

Tamiflu

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Tamiflu:

Diarrhea; nausea; stomach pain; vomiting.

Seek medical attention right away if any of these SEVERE side effects occur when using Tamiflu:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); abnormal behavior; confusion; hallucinations; mood or mental changes; reddened, blistered, peeling, or swollen skin; seizures; severe or persistent nausea, vomiting, or diarrhea; symptoms of infection (eg, fever, chills, persistent sore throat).

Tamiflu Suspension

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Tamiflu Suspension:

Diarrhea; nausea; stomach pain; vomiting.

Seek medical attention right away if any of these SEVERE side effects occur when using Tamiflu Suspension:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); abnormal behavior; confusion; hallucinations; mood or mental changes; reddened, blistered, peeling, or swollen skin; seizures; severe or persistent nausea, vomiting, or diarrhea; symptoms of infection (eg, fever, chills, persistent sore throat).

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Tamiflu Side Effects - for the Professional

Tamiflu

Treatment Studies in Adult Patients

A total of 1171 patients who participated in adult phase III controlled clinical trials for the treatment of influenza were treated with Tamiflu. The most frequently reported adverse events in these studies were nausea and vomiting. These events were generally of mild to moderate degree and usually occurred on the first 2 days of administration. Less than 1% of subjects discontinued prematurely from clinical trials due to nausea and vomiting.

Adverse events that occurred with an incidence of ≥1% in 1440 patients taking placebo or Tamiflu 75 mg twice daily in adult phase III treatment studies are shown in Table 3. This summary includes 945 healthy young adults and 495 "at risk" patients (elderly patients and patients with chronic cardiac or respiratory disease). Those events reported numerically more frequently in patients taking Tamiflu compared with placebo were nausea, vomiting, bronchitis, insomnia, and vertigo.

Prophylaxis Studies in Adult Patients

A total of 4187 subjects (adolescents, healthy adults and elderly) participated in phase III prophylaxis studies, of whom 1790 received the recommended dose of 75 mg once daily for up to 6 weeks. Adverse events were qualitatively very similar to those seen in the treatment studies, despite a longer duration of dosing. Events reported more frequently in subjects receiving Tamiflu compared to subjects receiving placebo in prophylaxis studies, and more commonly than in treatment studies, were aches and pains, rhinorrhea, dyspepsia and upper respiratory tract infections. However, the difference in incidence between Tamiflu and placebo for these events was less than 1%. There were no clinically relevant differences in the safety profile of the 942 elderly subjects who received Tamiflu or placebo, compared with the younger population.

Table 3 Most Frequent Adverse Events in Studies in Naturally Acquired Influenza in Patients 13 Years of Age and Older
Treatment Prophylaxis
Adverse Event Placebo

N=716
Oseltamivir
75 mg bid
N=724
Placebo/No Prophylaxis*
N=1688
Oseltamivir
75 mg qd
N=1790
*
The majority of subjects received placebo; 254 subjects from a randomized, open-label post exposure prophylaxis study in households did not receive placebo or prophylaxis therapy.
Nausea (without vomiting) 40 (6%) 72 (10%) 56 (3%) 129 (7%)
Vomiting 21 (3%) 68 (9%) 16 (1%) 39 (2%)
Diarrhea 70 (10%) 48 (7%) 40 (2%) 50 (3%)
Bronchitis 15 (2%) 17 (2%) 22 (1%) 15 (1%)
Abdominal pain 16 (2%) 16 (2%) 25 (1%) 37 (2%)
Dizziness 25 (3%) 15 (2%) 21 (1%) 24 (1%)
Headache 14 (2%) 13 (2%) 306 (18%) 326 (18%)
Cough 12 (2%) 9 (1%) 119 (7%) 94 (5%)
Insomnia 6 (1%) 8 (1%) 15 (1%) 22 (1%)
Vertigo 4 (1%) 7 (1%) 4 (<1%) 4 (<1%)
Fatigue 7 (1%) 7 (1%) 163 (10%) 139 (8%)

Adverse events included are: all events reported in the treatment studies with frequency ≥1% in the oseltamivir 75 mg bid group.

Additional adverse events occurring in <1% of patients receiving Tamiflu for treatment included unstable angina, anemia, pseudomembranous colitis, humerus fracture, pneumonia, pyrexia, and peritonsillar abscess.

Treatment Studies in Pediatric Patients

A total of 1032 pediatric patients aged 1 to 12 years (including 698 otherwise healthy pediatric patients aged 1 to 12 years and 334 asthmatic pediatric patients aged 6 to 12 years) participated in phase III studies of Tamiflu given for the treatment of influenza. A total of 515 pediatric patients received treatment with Tamiflu for Oral Suspension.

Adverse events occurring in ≥1% of pediatric patients receiving Tamiflu treatment are listed in Table 4. The most frequently reported adverse event was vomiting. Other events reported more frequently by pediatric patients treated with Tamiflu included abdominal pain, epistaxis, ear disorder, and conjunctivitis. These events generally occurred once and resolved despite continued dosing. They did not cause discontinuation of drug in the vast majority of cases.

The adverse event profile in adolescents is similar to that described for adult patients and pediatric patients aged 1 to 12 years.

Prophylaxis in Pediatric Patients

Pediatric patients aged 1 to 12 years participated in a postexposure prophylaxis study in households, both as index cases (134) and as contacts (222). Gastrointestinal events were the most frequent, particularly vomiting. The adverse events noted were consistent with those previously observed in pediatric treatment studies.

Table 4 Most Frequent Adverse Events Occurring in Children Aged 1 to 12 Years in Studies in Naturally Acquired Influenza
Treatment Trials* Household Prophylaxis Trial
Adverse Event Placebo

N=517
Oseltamivir
2 mg/kg bid
N=515
No Prophylaxis
N=87
Prophylaxis with Oseltamivir
QD
N=99
*
Pooled data from Phase III trials of Tamiflu treatment of naturally acquired influenza.
A randomized, open-label study of household transmission in which household contacts received either prophylaxis or no prophylaxis but treatment if they became ill. Only contacts who received prophylaxis or who remained on no prophylaxis are included in this table.
Unit dose = age-based dosing
Vomiting 48 (9%) 77 (15%) 2 (2%) 10 (10%)
Diarrhea 55 (11%) 49 (10%) - 1 (1%)
Otitis media 58 (11%) 45 (9%) 2 (2%) 2 (2%)
Abdominal pain 20 (4%) 24 (5%) - 3 (3%)
Asthma (including aggravated) 19 (4%) 18 (3%) 1 (1%) 1 (1%)
Nausea 22 (4%) 17 (3%) 1 (1%) 4 (4%)
Epistaxis 13 (3%) 16 (3%) - 1 (1%)
Pneumonia 17 (3%) 10 (2%) 2 (2%) -
Ear disorder 6 (1%) 9 (2%) - -
Sinusitis 13 (3%) 9 (2%) - -
Bronchitis 11 (2%) 8 (2%) 2 (2%) -
Conjunctivitis 2 (<1%) 5 (1%) - -
Dermatitis 10 (2%) 5 (1%) - -
Lymphadenopathy 8 (2%) 5 (1%) - -
Tympanic membrane disorder 6 (1%) 5 (1%) - -
Age Prophylaxis (10 days)
1-2 years 30 mg QD
3-5 years 45 mg QD
6-12 years 60 mg QD

Adverse events included in Table 4 are: all events reported in the treatment studies with frequency ≥1% in the oseltamivir 75 mg bid group.

Observed During Clinical Practice

The following adverse reactions have been identified during postmarketing use of Tamiflu. Because these reactions are reported voluntarily from a population of uncertain size, it is not possible to reliably estimate their frequency or establish a causal relationship to Tamiflu exposure.

Body as a Whole: Swelling of the face or tongue, allergy, anaphylactic/anaphylactoid reactions

Dermatologic: Dermatitis, rash, eczema, urticaria, erythema multiforme, Stevens-Johnson Syndrome, toxic epidermal necrolysis

Digestive: Hepatitis, liver function tests abnormal

Cardiac: Arrhythmia

Gastrointestinal disorders: Gastrointestinal bleeding, hemorrhagic colitis

Neurologic: Seizure

Metabolic: Aggravation of diabetes

Psychiatric: Delirium, including symptoms such as altered level of consciousness, confusion, abnormal behavior, delusions, hallucinations, agitation, anxiety, nightmares

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Side Effects by Body System

General

The use of oseltamivir has been studied in nearly 1200 patients with influenza in adult phase 3 controlled clinical trials. Less than 1% of these patients discontinued oseltamivir therapy early due to the most commonly reported adverse side effects--nausea and vomiting. No other side effects associated with the use of oseltamivir were more common among treated patients compared with placebo. In phase 3 studies there was no relationship between drug exposure and adverse events or laboratory abnormalities at dosages up to 1000 mg per day.

Adverse effects in prophylaxis studies with adults and adolescents were similar to those in treatment studies. Side effects that occurred more frequently than in treatment studies were aches and pains, rhinorrhea, dyspepsia and upper respiratory tract infections. Gastrointestinal side effects occurred most frequently in prophylaxis studies with pediatric patients.

Gastrointestinal

Gastrointestinal side effects have been the most commonly reported and have included nausea (7% to 9.9%), vomiting (2.1% to 9.4%), diarrhea (3.2% to 6.6%), abdominal pain (2%), and pseudomembranous colitis (less than 1%). While treated patients might be expected to have nausea and vomiting anyway, the incidence of these problems among treated patients was 2 to 3 times higher among patients who received oseltamivir. Gastrointestinal bleeding and hemorrhagic colitis have been reported during postmarketing experience.

Respiratory

Respiratory side effects have included bronchitis (0.7% to 2.3%) and cough (1.2% to 5.6%). The incidences were similar or higher among placebo patients and may represent symptoms of underlying influenza infection. Pneumonia has been reported (less than 1%) and may also be a symptom of underlying disease. Nasopharyngitis, congestion, rhinitis, and dry, sore throat have also been reported.

Nervous system

Nervous system side effects have included dizziness (2.1%), headache (1.8% to 20.1%), insomnia (1.2%), and vertigo (0.3% to 1%). (The incidences were similar or higher among placebo patients and may represent symptoms of underlying influenza infection.) Seizure has been reported during postmarketing experience.

Psychiatric

Psychiatric side effects have included delirium (including symptoms such as altered level of consciousness, confusion, abnormal behavior, delusions, hallucinations, agitation, anxiety, nightmares) during postmarketing experience.

Abnormal behavior and delirium leading to injury, with fatal outcomes in some cases, with the use of oseltamivir in influenza patients have been reported. Although frequency is unknown, based on oseltamivir usage, these events appear to be uncommon. These events were primarily reported in pediatric patients and often had an abrupt onset and rapid resolution. Since influenza may be associated with neurologic and behavioral symptoms (including hallucinations, delirium, and abnormal behavior, with fatal outcomes in some cases), oseltamivir's contribution to these effects has not been established.

Other

Other side effects have included fatigue (1% to 7.9%), humerus fracture (less than 1%), pyrexia (less than 1%), and peritonsillar abscess (less than 1%). Causality has not been established. Drowsiness and malaise have also been reported.

Hematologic

Hematologic side effects have included anemia (less than 1%) and pancytopenia. Causality has not been established.

Hypersensitivity

Hypersensitivity reactions have included anaphylaxis, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, and swelling of the face or tongue.

Dermatologic

Dermatologic side effects have included rash, toxic epidermal necrolysis, and erythema multiforme.

Hepatic

Hepatic side effects have included hepatitis and abnormal liver function tests. Hepatic failure has also been reported; however, causality has not been established.

Cardiovascular

Cardiovascular side effects have included angina (less than 1%), arrhythmia, and sudden cardiopulmonary arrest. Causality has not been established.

Metabolic

Metabolic side effects have included aggravation of diabetes and hyperglycemia. Causality has not been established.

Immunologic

Immunologic side effects have included sepsis. Causality has not been established.

Musculoskeletal

Musculoskeletal side effects have included arthralgia in at least one patient.

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More resources:

Drugs.com Tamiflu

PDR Tamiflu

MedFacts Tamiflu

Micromedex Tamiflu - Includes detailed dosage instructions.

FDA Tamiflu

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date, and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This information does not endorse drugs, diagnose patients, or recommend therapy. This drug information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug of drug combination is safe, effective, or appropriate for any given patient. Drugs.com does not assume any responsibility for any aspect of healthcare administered with the aid of information provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse, or pharmacist.


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