I was hoping for some additional information from you, but I know you must be busy, so I'll send your answer, now.
Samantha could be wheezing due to asthma, bronchitis or another respiratory condition.
Wheezing may also be due to allergies. If you use scented candles, spray, plug in or solid air fresheners, or if there's a smoker in the house, these and other items may be causing an allergic reaction in Samantha. In addition, there are other medications that should not be given at the same time as methimazole. Please see the following:
It would be best to have Samantha evaluated in person by a vet, as soon as possible, so you can get a definite diagnosis and treatment, if needed.
I hope all will be well with Samantha! I'll check back with you in a few days, to see how she's doing.
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