Use of Fentanyl Patch in Partial Doses Than the Original

Fentanyl is considered a potent synthetic opioid widely used in anesthesiology, for short and long-term pain management, and for sedation. The fentanyl patch is constructed like a matrix, a system based on a polyacrylate net with fentanyl that attaches directly onto the skin. The doses available today are from 12µg/h, 25, 50, 75, to 100 µg/h. Despite the variable doses available, often in certain patients as the elderly or children, there is a need for slower titration than the 12 µg/h currently available. In this study, the investigators aim to evaluate pain control and to examine the blood fentanyl concentration of patients on a fix dose of fentanyl patch up to 100 µg/h every two or three days, and compare it with pain control and concentration levels obtained from a similar dose patch, but after cutting the patch into two. The study will take place at the pain clinic of Clalit Health Services-South District (CHS-SD), and the Negev home palliative care unit. In CHS-SD there are approximately 300 patients treated regularly with opioids and about 120 patients in the home palliative care unit. A sample of 95 patients will be recruited. Once consent form is signed, blood samples will be collected twice: 1. At the time of the visit; 2. After 144 hours (about 6 days) from the first sample, and at least 36 hours after replacing the cut patch. Pain management will be evaluated at both visits using the Brief Pain Inventory (Hebrew version) - BPI questionnaire, and rescue doses used before and after the cutting of the patch. The blood samples will be transferred to the laboratory for testing of fentanyl concentration levels.

A sample of 95 patients will be recruited. Once consent form is signed, blood samples will be collected twice: 1. At the time of the visit; 2. After 144 hours (about 6 days) from the first sample, and at least 36 hours after replacing the cut patch. Pain management will be evaluated at both visits using the Brief Pain Inventory (Hebrew version) - BPI questionnaire, and rescue doses used before and after the cutting of the patch. The blood samples will be transferred to the laboratory for testing of fentanyl concentration levels.

2 ml blood samples will be transferred under refrigerated conditions to the lab for a chromatography test using spectrometry testing for fentanyl and nurofentanyl. The change of blood concentration levels of fentanyl and nurofentanyl will be examined.

1. At the time of the visit; 2. After 144 hours (about 6 days) from the first sample, and at least 36 hours after replacing the cut patch

Pain management will be evaluated at both visits using the Brief Pain Inventory (Hebrew version) - BPI questionnaire. We will examine the change of patients pain assessment

1. At the time of the visit; 2. After 144 hours (about 6 days) from the first sample, and at least 36 hours after replacing the cut patch

Inclusion Criteria: patients suffering from chronic pain on a fixed dose of fentanyl patch for over two weeks, with a maximum dose of 100 µg/h every two or three days, and have given their informed consent will be included in the study. Exclusion Criteria: Patients with cognitive problems non-Hebrew speaking patients that their medical condition prevents them from participation in the study.