There are many important precautions and warnings with flunisolide inhalers to be aware of. Among these precautions are the possibility that the flunisolide inhaler may slow the growth of some children and teenagers and the risk of infections, thrush, and glaucoma or cataracts in some people who take this medicine. There are also certain people who should not use a flunisolide inhaler at all, such as those who are allergic to any components used to make the medication.

• Not had chickenpox or the measles (or have not been vaccinated against them)
• Eczema (or atopic dermatitis)
• Tuberculosis, herpes, or any other infections
• Glaucoma or cataracts
• Any allergies, including allergies to food, dyes, or preservatives.
   

• Pregnant or thinking of becoming pregnant
• Breastfeeding.
   

• If you are switching from an oral steroid to a flunisolide inhaler (which is an inhaled steroid), your healthcare provider should decrease your dose of oral steroid very slowly. Stopping an oral steroid too quickly can be very dangerous.
   
• The flunisolide inhaler is not a fast-acting asthma medication and cannot replace fast-acting rescue inhalers. Do not use a flunisolide inhaler to treat an asthma attack. Everyone using a flunisolide inhaler should also have a rescue asthma medication available at all times. Let your healthcare provider know if you need to use your rescue inhaler more frequently than usual, as this may be a sign of worsening asthma.
   
• Flunisolide inhalers can cause an immediate worsening of asthma symptoms. If this happens, use your rescue inhaler (such as albuterol) as needed and contact your healthcare provider for further instruction.
   
• Flunisolide is a steroid and may suppress the immune system. Although this is more likely to occur with oral steroids, it is still possible with inhaled steroids (such as flunisolide inhalers). You may be at a higher risk of infections. Certain infections (such as chickenpox or the measles) may be more dangerous if you are using a flunisolide inhaler. During treatment with a flunisolide inhaler, let your healthcare provider know right away if you are exposed to chickenpox or the measles (if you have not had these infections and have not been vaccinated against them).
   
• Like all steroids, flunisolide inhalers may slow the growth of children and teenagers. Usually, this slowing of growth is small, with children growing about half a centimeter less per year. Contact your child's healthcare provider if you are concerned about slow growth in your child.
   
• Flunisolide inhalers can cause thrush (a yeast infection of the mouth or throat). In order to help prevent this, rinse your mouth with water (without swallowing) after each dose.
   
• Inhaled steroids (including flunisolide inhalers) can cause glaucoma or cataracts (conditions of the eyes).
   
• Before starting a flunisolide inhaler, be sure to tell your healthcare provider if you currently have any type of infection. Also let your healthcare provider know if you have ever had tuberculosis or a herpes infection of the eye, as the flunisolide inhaler may weaken the immune system, allowing these infections to worsen.
   
• Flunisolide inhalers can interact with certain other medications (see Drug Interactions With Flunisolide Inhalers).
   
• Flunisolide inhalers are considered a pregnancy Category C medication. This means that they may not be safe to use during pregnancy. Talk with your healthcare provider about the risks and benefits of using a flunisolide inhaler during pregnancy (see Aerobid and Pregnancy for more information).
   
• It is not known if inhaled flunisolide (the active ingredient of the flunisolide inhaler) passes through breast milk. Therefore, if you are breastfeeding or plan to start breastfeeding, be sure to talk with your healthcare provider about using a flunisolide inhaler (see Aerobid and Breastfeeding for more information).