In my experience, there are many reasons why pain may not be controlled including patients avoiding taking their breakthrough medications due to unpleasant side effects. (I see you mentioned this may be the case). This is where open lines of communication between patient/family and provider is key. It is sometimes hard to talk about pain issues, but this is such an important topic!
Pain management in cancer is very dynamic. If one regimen does not work, then another must be attempted. Opioid rotation, or switching from one opioid to another may be necessary, as well as adjustments in dosage.
I frequently see Fentanyl patches used to manage pain, along with an oral opioid for breakthrough pain. I also see exactly what your MIL is receiving, a long acting opioid and a short acting for breakthrough. If her current prescribed medications are not dropping her pain below a 5/10 on a 0-10 scale (and she is taking them as prescribed) then it is time for medication adjustment.
One important teaching topic which I discuss with patients and families very often, is to understand that there may still be pain, but to decide on what pain level is tolerable. What I mean by tolerable, is the pain level that the patient is comfortable at, where they are able to function well without being sedated. For some people this is 1/10, and others it is higher. It is good to try to understand how the individual feels about their pain, and what their expectations are as far as management.
As a nurse, I am generally concerned if a patient has pain upwards of 4-5 as they may escalate rapidly, so I generally medicate accordingly before the pain is out of control. It is much more difficult to decrease pain if it has gotten to an 8,9,10/10 then if at a 4 or 5/10.
http://www.mayoclinic.org/diseases-cond … 45118?pg=1
Regarding concerns about a low platelet count or thrombocytopenia, 45 is low, but I see physicians often wait to transfuse until 15-10,000 (10) or less. (Due to chemotherapy). Of course, always watch for signs or symptoms of bleeding, i.e., a nose bleed that does not stop, bleeding from the gums after brushing the teeth, blood in the urine or stool, a cut that will not stop bleeding, excessive bruising, petechiae, or a sudden and severe headache. If a fall occurs and the patient with a low platelet count bumps their head, bring them to the ER as they should get a CT of the head done.
Platelet count will rebound between chemotherapy infusions as well as RBCs, hemoglobin/hematocrit. Sometimes it may take longer though due to many factors.
Here is some info on thrombocytopenia (low platelets)
http://news.cancerconnect.com/thrombocy … -overview/
http://www.cancer.net/navigating-cancer … ocytopenia
Another issue with platelets (and blood for that matter), is that there is a nationwide shortage of blood products. Blood banks and physicians are very judicious in their use of blood and blood products, and transfusions do not come without risk as well. Benefit versus harm must always be taken into consideration.
https://www.medpagetoday.com/hospitalba … tice/66488
I hope this information helps you! I know it is a lot!