opioid narcotics are the cornerstone drugs for managing severe cancer pain , with or without adjuvant drugs .
fentanyl is a synthetic opioid - agonist that primarily interacts with the mu - opioid receptor .
transdermal fentanyl patches are designed to deliver fentanyl at a constant rate from a reservoir .
there have been many studies on the efficacy and convenience of transdermal fentanyl patches for controlling both cancer pain and non - cancer pain [ 2 - 4 ] . compared with other opioids ,
fentanyl patches have been associated with better pain relief , less constipation and they enhance the quality of life .
especially , these patches are a good choice for patients with dysphagia , changes of consciousness and those who need opioid rotation due to side effects .
although it is well known that there is no upper dose limit when using opioids , high doses of opioids are commonly feared by physicians , patients and caregivers .
we describe here a patient with advanced cholangiocarcinoma who obtained a good pain control with high doses of transdermal fentanyl for cancer pain .
a 52-year - old man was referred to our hospital because of cancer pain that was 4/10 to 5/10 on a numeric rating scale ( nrs ) .
three months previously , he had been diagnosed with locally advanced cholangiocarcinoma at other hospital ( fig .
he was taking non - steroidal anti - inflammatory drugs due to his mild abdominal pain .
his pain was mainly dull , being located in the right upper quadrant of the abdomen .
the cancer pain diminished his appetite and it often woke him from sleeping at night .
we initially prescribed tramadol ( 300 mg / day ) and amitriptyline ( 10 mg / day ) , but his background pain was not effectively relieved .
thus , we administered transdermal fentanyl patches ( 12.5 g / hr ) for the background pain and oxycodone immediate release ( oir ) tablets for the breakthrough pain , and this treatment brought a dramatic improvement of his pain . yet after 10 days , the background pain was abruptly aggravated ( 6/10 on the nrs ) .
the dose of fentanyl was gradually increased to 250 g / hr over 2 months and his pain became tolerable ( 2/10 on nrs ) .
after about 4 weeks on this dose of fentanyl patch , his pain intensity became worse and it eventually reached up to 8/10 to 9/10 on nrs . on admission , we added oxycodone ( 20 to 200 mg / day ) and increased the dose of amitriptyline to 40 mg / day , but the patient failed to obtain an analgesic effect .
abdominal ct was done to find any unknown pain - relieving factors at that time , and the ct showed a severe intrahepatic ductal dilatation ( fig .
percutaneous transhepatic biliary drainage was performed at once , which did not relieve his pain .
thereafter , he refused all invasive procedures , including celiac plexus block or epidural block .
in the 2 weeks before the patient 's death , the dose of transdermal fentanyl reached 1,050 g / hr ( fig .
the patient obtained a good pain control ( nrs 2/10 to 3/10 ) with no exacerbation of side effects .
although most cancer pain can be relieved , effectively controlling the pain of cancer patients is often problematic .
one of the reasons for this is related to the so - called opioidphobia by physicians , patients and caregivers .
many clinicians are afraid that high - dose opioids may lead to respiratory depression and hasten the death of patients .
however , studies describing the morphine dosage used for hospice patients demonstrated that high - dose morphine has a high safety profile and it does n't adversely affect the survival of the patients . for our case reported here , we mostly applied transdermal fentanyl patches for the cancer pain .
we initially administered a 12.5 g / hr fentanyl patch for background pain that was 4/10 to 5/10 on the nrs , which brought about dramatic pain control . with time , however , the patient 's cancer pain was aggravated and the dose of transdermal fentanyl was gradually increased to 250 g / hr . when the patient 's pain intensity became worse ( 8/10 to 9/10 on nrs ) in spite of being on 250 g / hr transdermal fentanyl , we added oxycodone tablets .
several preliminary data suggested that partial opioid rotation and opioid combinations may be beneficial for patients with a poor analgesic effect after dose escalation . yet for our patient , adding the second opioid failed to achieve a good analgesic effect .
the highest dose of transdermal fentanyl reported in the english medical literature was 3,400 g / hr ( 34 patches of 100
g / hr each ) , which used for a 58-year - old woman with neuropathic pain due to a pancoast tumor of the lung .
however , this huge dose had no effect for relieving her from neuropathic pain . in our patient , we increased the dose of transdermal fentanyl to 1,050 g / hr ( 21 patches of 50
g / hr each ) over 3 weeks after discontinuing the oxycodone . at this dose ,
the patient could obtain good pain control during the last 2 weeks of his life , with no exacerbation of side effects .
to the best of our knowledge , we have reported here on the highest dose of transdemal fentanyl that was successfully used for a patient suffering from visceral cancer pain .
the administered fentanyl dose was equianalgesic to about a 4,000 mg dose of oral morphine/24 hours .
our experience suggests that if it is needed for controlling cancer pain , administering high - doses of opioids should not be feared .
however , orally administering this dose of opioids inevitably requires a large amount of tablets to be taken daily , which may induce more side effects and make patients uncomfortable .
therefore , high doses of fentanyl patches may be a good choice for those patients who need a megadose of opioids to control their cancer pain .
 we describe here a patient who obtained a good analgesic effect with high - dose fentanyl patches for controlling cancer pain . 
 a 52-year - old man was referred to our hospital because of severe cancer pain that was 7/10 on a numeric rating scale ( nrs ) . 
 he had been diagnosed with locally advanced cholangiocarcinoma 3 months previously . 
 we prescribed weak opioids and an antidepressant , but his pain was not relieved . 
 we introduced strong opioids ( transdermal fentanyl patches for the background pain and a short - acting opioid for the breakthrough pain ) and his pain was tolerable on 250 g / hr of fentanyl patches for 3 months . with time , however , his pain intensity became worse and this reached up to 8/10 to 9/10 on the nrs . 
 percutaneous transhepatic biliary drainage was performed , which did not relieve his pain . 
 we increased gradually the dose of transdermal fentanyl to 1,050 g / hr ( 20 patches ) . at this dose , 
 the patient was mentally alert , with good pain control ( nrs 2/10 to 3/10 ) and no exacerbation of side effects . 
 to the best of our knowledge , we report here on the highest dose of transdermal fentanyl that has been successfully used for treating a patient suffering from visceral cancer pain . 
INTRODUCTION
CASE REPORT
DISCUSSION