Can Dosage Of Hydrocodone Be Increased To Manage Pain?

my mother had gallbladder surgery. the prescription was wrote in oklahoma. cannot fill it here in texas. the pain killers that were prescibed to her was oxycodone 5mg 30qty. she also was given a refill on hydrocodone 7.5 325 mg. we could not fill them but the oncall dr talked w/ pharmacy and over the phone prescribed tramadol 5mg. it says to take 1 every 4 hrs. my mother is in horrible pain. question is , can she take 2 pills every 4 hrs instead of just the 1?