Before using zanamivir,
tell your doctor and pharmacist if you are allergic to zanamivir, any other medications, any food products, or lactose (milk proteins).
tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
tell your doctor if you have or have ever had asthma or other breathing problems; bronchitis (swelling of the air passages that lead to the lungs); emphysema (damage to air sacs in the lungs); or heart, kidney, liver, or other lung disease.
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking zanamivir, call your doctor.
you should know that zanamivir may cause serious or life-threatening breathing problems, more commonly in patients with an airways disease such as asthma or emphysema. If you have trouble breathing or have wheezing or shortness of breath after your dose of zanamivir, stop using zanamivir and get medical attention immediately. If you have difficulty breathing, and have been prescribed a rescue medication, use your rescue medication immediately and then call for medical attention. Do not inhale any more zanamivir without first talking to your doctor.
you should know that people, especially children and teenagers, who have the flu may become confused, agitated, or anxious, and may behave strangely, have seizures or hallucinate (see things or hear voices that do not exist), or harm or kill themselves. You or your child may develop these symptoms whether or not you or your child uses zanamivir, and the symptoms may begin shortly after starting treatment if you do use the medication. If your child has the flu, you should watch his or her behavior very carefully and call the doctor right away if he or she becomes confused or behaves abnormally. If you have the flu, you, your family, or your caregiver should call the doctor right away if you become confused, behave abnormally, or think about harming yourself. Be sure that your family or caregiver knows which symptoms may be serious so they can call the doctor if you are unable to seek treatment on your own.
ask your doctor if you should receive a flu vaccination each year. Zanamivir does not take the place of a yearly flu vaccine. If you received or plan to receive the intranasal flu vaccine (FluMist; flu vaccine that is sprayed into the nose), you should tell your doctor before taking zanamivir. Zanamivir may interfere with the activity of the intranasal flu vaccine if it is taken up to 2 weeks after or up to 48 hours before the vaccine is administered.