Tamiflu not the final answer: Tamiflu is effective but only in them who may not need it.

HCFI New Thursday 13th August Delhi: Off late a lot of confusion has been created amongst the public mind about the safety of the drug oseltamivir in the media. But the available evidence based literature is clear about that it is safe said Dr. KK Aggarwal President, Heart Care Foundation of India, BSNL Dil Ka Darbar, MTNL Perfect Health Mela and Director, IMA AKN Sinha Institute but its efficacy in people who needs is in doubt.

Only 2% require admission and are the ones who have underlying chronic comorbid condition. We must learn from the evidences from      US.
1. Among 30 hospitalized patients in California, 19 (64 percent) had underlying medical conditions, five were pregnant (17 percent), six (20 percent) required intensive care unit admission, and four (13 percent) had respiratory failure. Of the 25 patients who had chest radiographs, 15 (60 percent) showed evidence of pneumonia. None had microbiologic evidence of secondary bacterial pneumonia.

2. Among 553 patients with confirmed or probable pandemic H1N1 influenza A in California, the most common risk factors for influenza complications were chronic lung disease (asthma or chronic obstructive pulmonary disease, 37 percent), immunosuppressive conditions (17 percent), cardiac disease (17 percent), pregnancy (17 percent), diabetes mellitus (13 percent), and obesity (13 percent). In short non pregnant high risk groups were COPD (37%), Heart patients diabetes obesity combined (43%) and immuno-compromised 17%.
Although elderly patients are considered to be at an increased risk for complications of influenza, pandemic H1N1 influenza A infections in such individuals have been uncommon to date possibly as a result of preexisting immunity against antigenically similar influenza viruses that circulated prior to 1957.

Tamiflu has some disease-related concerns:
 1. Cardiovascular disease: Use with caution in patients with chronic cardiac disease; efficacy has not been established.
 2. Respiratory disease: Use with caution in patients with respiratory disease; efficacy has not been established.
 3. Immunocompromised patients: Use with caution in immunocompromised patients; safety and efficacy for treatment or prophylaxis in immunocompromised patients have not been established.
4. Hepatic impairment: Use with caution in patients with severe hepatic impairment; safety and efficacy have not been established.
5. Renal impairment: Use with caution in patients with renal impairment; dosage adjustment is required for creatinine clearance <30 mL/minute.
6. Efficacy has not been established if treatment begins >40 hours after the onset of symptoms.

The drug is safe in general population: prophylaxis
The most common toxicities reported with oseltamivir have been nausea and vomiting, which occur in approximately 15 percent of recipients. These side effects are usually mild and limited to the first day or two of treatment.

Post marketing reports have identified rare, but serious adverse events in patients with influenza who are taking neuraminidase inhibitors. These events include neuropsychiatric effects (delirium, hallucinations, confusion, abnormal behavior, convulsions, and encephalitis), severe skin reactions, and death. Most of the reports of neuropsychiatric events involved oseltamivir and occurred in children living in Japan, where the use of neuraminidase inhibitors is widespread. However, a subsequent study has not demonstrated a causal association between neuraminidase inhibitors and abnormal behavior, and Japan's health
ministry is considering whether to modify the warning.

Both zanamivir and oseltamivir are generally well tolerated. The delivery system for zanamivir (inhaled dry powder) has raised concerns about use in patients with pulmonary disease, such as chronic obstructive pulmonary disease (COPD) or asthma. Respiratory distress associated with zanamivir has been reported in a patient presenting with an exacerbation of COPD.The safety of this drug in patients with severe COPD or asthma has not been established, and data from a placebo-controlled trial enrolling such patients suggest an increased risk of a substantial (greater than 20 percent) reduction in FEV1 in zanamivir recipients.

Zanamivir is not recommended for individuals with underlying respiratory disease such as asthma or chronic obstructive pulmonary disease. If it is used in such patients, a fast-acting bronchodilator should be readily available.