The top diagnosis for a wheezing cat is asthma.  Pneumonia, allergies, heart disease, and other causes cannot be ruled out.  Your veterinarian will examine your cat, auscultate (listen) to the chest, and take x-rays to evaluate the lung fields, heart, and vessels in the thoracic cavity.
Asthma is treated with oral steroids, oral bronchodilators (medications that open the airways), and some inhalant medications.  Eliminating aerosol irritants like smoke, cleaners and sprays often do a great job at controlling asthma.
Do NOT use your inhaler on your cat without consulting your veterinarian and without a diagnosis.  Not all human medications are safe for cats and the doses often vary.

 I am not a vet but I am in the medical field. Inhalers are calculated doses according to condition etc. You must inhale deeply to get it in the lungs. Then rinse your mouth to avoid a buildup on the tongue and throat. Usually those who use inhalers feel better to gargle after taking there inhaler to avoid a fungus type growth from the inhaler and buildup. If you give your cat an inhaler how much do you know how to give him --you cant know-you cant tell him to breath deep while inhaling and breath out slowly. A cat also cant cup his mouth around the inhaler-You cant have him breath hard enough to check his O2 saturation so I guess the answer would be no. The medicine would stay in his/her mouth and throat. Also inhalers tend to speed up the heart to open the air passages- if you should give to much like an adult does the cats heart would never make it. Talk to a vet but don't try human meds for animals they have a total different response.