As a workaround, you can download a local dictionary of medical and pharmacy terms, and then fuzzy-match your sub-string to the tokens in your local dictionary. You may be able to get tokens from the API itself, for example, and end-point that returns a list of all drug names.
This isn't real fuzzy-matching, because you are finding sub-tokens in tokens, and not changing spellings, e.g.
url = 'https://api.fda.gov/drug/label.json?search=brand_name:'
text = 'anadol'
with open('meddict.txt','r') as f:
d = f.readlines()
# d = ['panadol','aspirin','ibuprofin']
for item in d:
if text in item:
print 'fuzzy match',item,text
r = requests.get(url+item)
But you can also do a fuzzy-match between your search string and the medical dictionary, and then pass the words with a high-enough match score to the web service.
I'll search a bit for an open medical dictionary, and perhaps it's worth opening a new question.