PHARMACOTHERAPY III PHCY 510 University of Nizwa College of Pharmacy and Nursing School of Pharmacy PHARMACOTHERAPY III PHCY 510 Lecture 8 Infectious Diseases “Influenza” Dr. Sabin Thomas, M. Pharm. Ph. D. Assistant Professor in Pharmacy Practice School of Pharmacy, CPN University of Nizwa

Course Outcome Upon completion of this lecture the students will be able to Describe the epidemics, pandemics and antigenic shift, pathogenesis, prevention, post exposure prophylaxis for Influenza. Individualize the treatment of influenza.

Influenza is a viral illness among persons younger than age 65 years. Seasonal influenza epidemics result in millions influenza cases and death each year. The route of influenza transmission is person-to-person via inhalation of respiratory droplets, which can occur when an infected person coughs or sneezes. The incubation period for influenza ranges between 1 and 4 days, with an average incubation of 2 days. Adults are considered infectious until 5 days after the onset of illness, while children can be infectious for longer than 10 days.

Signs and Symptoms Rapid onset of fever, myalgia, headache, malaise, nonproductive cough, sore throat, and rhinitis. Nausea, vomiting, and otitis media are common in children. It resolves in approximately 3 to 7 days, although cough and malaise may persist for more than 2 weeks. Lab Test Gold standard for diagnosis of influenza is viral culture.

Prevention Prevent infection through vaccination. Hand hygiene, basic respiratory etiquette (cover your cough, throw tissues away), and contact avoidance, are also important in preventing the spread of influenza. The two vaccines currently available for prevention of influenza are the trivalent influenza vaccine (TIV) and the live-attenuated influenza vaccine (LAIV). The specific strains included in the vaccine each year change based on antigenic drift.

The most frequent adverse effect associated with TIV is soreness at the injection site that lasts for less than 48 hours. TIV may cause fever and malaise in those who have not previously been exposed to the viral antigens in the vaccine. Allergic-type reactions (hives, systemic anaphylaxis) rarely occur after influenza vaccination and are likely a result of a reaction to residual egg protein in the vaccine.

Vaccination should be avoided in persons Who are not at high risk for influenza complications. Who have experienced Guillain-Barré syndrome within 6 weeks of receiving a previous influenza vaccine. LAIV administration ADRs included runny nose, congestion, sore throat, and headache. LAIV should not be given to immunosuppressed patients.

Postexposure Prophylaxis The neuraminidase inhibitors Oseltamivir and zanamivir are used for treatment and prevention of Influenza A (H1 N1; Swine & Avian) and B. Amantadine was used for influenza A virus (? Now Resistant) Pregnant women, regardless of trimester, should receive annual influenza vaccination with TIV but not with LAIV. Adamantanes and neuraminidase inhibitors are not recommended during pregnancy because of concerns regarding the effects of the drugs on the fetus.

Immunocompromised hosts should receive annual influenza vaccination with TIV but not LAIV. TREATMENT Individual at risk and eligible for treatment are: Persons at high risk of serious illness and/or complications who cannot be vaccinated. Asthma and COPD patients Cardiovascular disease patients Chronic kidney disease patients Diabetic patients Immunosuppressed patients (HIV, Cancer) Those who are over 65 years

Treatment Two classes of antiviral drugs available for treatment of influenza Adamantanes, amantadine and rimantadine Neuraminidase inhibitors, oseltamivir and zanamivir Oseltamivir is approved for treatment in those older than the age of 1 year. Zanamivir is approved for treatment in those older than the age of 7 years.