What is Zanamivir, and How Does It Work?
Zanamivir, marketed under the brand name Relenza, is an inhaled medication designed for the treatment and prevention of influenza, commonly known as the flu. This drug plays a pivotal role in reducing the spread of both influenza A and B viruses, the causative agents of the flu. Its mechanism of action involves inhibiting neuraminidase, an enzyme produced by viruses that facilitate their spread between infected and healthy cells. By impeding this viral transfer, Zanamivir helps alleviate symptoms and shorten the duration of influenza infection. Typically, initiating treatment within forty-eight hours of symptom onset yields optimal results, reducing symptom duration by an average of one day.
Zanamivir received FDA approval in July 1999 and is available over-the-counter.
What are the Side Effects of Zanamivir?
While Zanamivir is generally well-tolerated, some individuals may experience side effects. The most common ones include headaches, diarrhea, nausea, coughing, vomiting, disturbances in temperature regulation, and dizziness. Additionally, other noteworthy side effects encompass changes in appetite, fever, chills, weakness, sinusitis, ear-nose-throat infections, skin reactions, muscle or joint pain, allergic reactions, bronchospasm, and behavioral disturbances.
Patients with respiratory conditions may encounter breathing difficulties due to irritation caused by Zanamivir particles from the inhaler. If respiratory issues arise, discontinuation of Zanamivir is advised. Individuals with asthma or heightened sensitivity to inhaled particles should keep a fast-acting bronchodilator on hand to manage potential breathing problems associated with Zanamivir use.
What is the Dosage for Zanamivir?
Zanamivir is administered via oral inhalation. The recommended dosage involves two inhalations (5 mg each) twice daily, approximately 12 hours apart, for five days. On the first treatment day, two doses separated by at least two hours are suggested. For influenza prevention within a household setting, the recommended dose is 10 mg once daily for ten days. In a community setting, the preventive dose is 10 mg once daily for 28 days. Prompt initiation of treatment upon symptom development enhances efficacy.
Which Drugs or Supplements Interact with Zanamivir?
Zanamivir may interfere with live attenuated flu vaccine injections due to its impact on viral replication. Therefore, live attenuated flu vaccine administration should be avoided from 2 weeks before to 48 hours after Zanamivir use. The trivalent inactivated influenza vaccine, however, is considered safe during Zanamivir usage.
Is Zanamivir Safe During Pregnancy or Breastfeeding?
The Centers for Disease Control (CDC) states that Zanamivir is not contraindicated during pregnancy, as the benefits outweigh potential risks. While it is uncertain whether Zanamivir is excreted in breast milk, nursing women who develop the flu after childbirth are recommended to undergo antiviral drug treatment.
Additional Considerations for Zanamivir
Zanamivir is available in inhalation powder form with a concentration of 5 mg per inhalation. It should be stored at room temperature between 15°C to 30°C (59°F to 86°F).
In summary, Zanamivir (Relenza) is a prescription inhaled medication effective in treating and preventing influenza, including H1N1 (swine flu). Prior to usage, it is crucial to review the side effects, drug interactions, warnings, precautions, and patient information associated with this medication.