DURAGESIC (fentanyl transdermal system) is a transdermal system containing fentanyl. The chemical name is N-Phenyl-N-(1-(2-phenylethyl)-4-piperidinyl) propanamide.
The molecular weight of fentanyl base is 336.5, and the empirical formula is C22H28N2O. The n-octanol: water partition coefficient is 860:1. The pKa is 8.4.
System Components And Structure
The amount of fentanyl released from each system per hour is proportional to the surface area (25 mcg/h per 10.5 cm²). The composition per unit area of all system sizes is identical.
DURAGESIC is indicated for the management of pain in opioid-tolerant patients, severe enough to require daily, around-the-clock, long-term opioid treatment and for which alternative treatment options are inadequate.
Patients considered opioid-tolerant are those who are taking, for one week or longer, at least 60 mg of morphine daily, or at least 30 mg of oral oxycodone daily, or at least 8 mg of oral hydromorphone daily, or an equianalgesic dose of another opioid.
Limitations Of Use
Because of the risks of addiction, abuse, and misuse with opioids, even at recommended doses, and because of the greater risks of overdose and death with extended-release opioid formulations, reserve DURAGESIC for use in patients for whom alternative treatment options (e.g., non-opioid analgesics or immediate-release opioids) are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain.
DURAGESIC should be prescribed only by healthcare professionals who are knowledgeable in the use of potent opioids for the management of chronic pain.
Due to the risk of respiratory depression, DURAGESIC is only indicated for use in patients who are already opioid-tolerant. Discontinue or taper all other extended-release opioids when beginning DURAGESIC therapy. As DURAGESIC is only for use in opioid-tolerant patients, do not begin any patient on DURAGESIC as the first opioid.
Patients considered opioid-tolerant are those who are taking at least 60 mg of morphine daily, or at least 30 mg of oral oxycodone daily, or at least 8 mg of oral hydromorphone daily or an equianalgesic dose of another opioid for a week or longer.
Initiate the dosing regimen for each patient individually, taking into account the patient’s prior analgesic treatment experience and risk factors for addiction, abuse, and misuse [see WARNINGS AND PRECAUTIONS]. Monitor patients closely for respiratory depression, especially within the first 24-72 hours of initiating therapy with DURAGESIC when serum concentrations from the initial patch will peak [see WARNINGS AND PRECAUTIONS].
The recommended starting dose when converting from other opioids to DURAGESIC is intended to minimize the potential for overdosing patients with the first dose.
Discontinue all other around-the-clock opioid drugs when DURAGESIC therapy is initiated.
While there are useful tables of opioid equivalents readily available, there is substantial interpatient variability in the relative potency of different opioid drugs and products. As such, it is preferable to underestimate a patient’s 24-hour fentanyl requirements and provide rescue medication (e.g., immediate-release opioid) than to overestimate the 24-hour fentanyl requirements which could result in adverse reactions. In a DURAGESIC clinical trial, patients were converted from their prior opioid to DURAGESIC using Table 1 as a guide for the initial DURAGESIC dose.
Consider the following when using the information in Table 1:
This is not a table of equianalgesic doses.
The conversion doses in this table are only for the conversion from one of the listed oral or parenteral opioid analgesics to DURAGESIC.
The table cannot be used to convert from DURAGESIC to another opioid. Doing so will result in an overestimation of the dose of the new opioid and may result in fatal overdose.
Nausea, vomiting, constipation, lightheadedness, dizziness, drowsiness, or headache may occur. Mild irritation, itching, or redness at the application site may also occur. Some of these side effects may decrease after you have been using this medication for a while. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
To prevent constipation, eat dietary fiber, drink enough water, and exercise. You may also need to take a laxative. Ask your pharmacist which type of laxative is right for you.
To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if you have any serious side effects, including: interrupted breathing during sleep (sleep apnea), mental/mood changes (such as agitation, confusion, hallucinations), severe stomach/abdominal pain, difficulty urinating, slow/fast/pounding heartbeat, signs of your adrenal glands not working well (such as loss of appetite, unusual tiredness, weight loss).
Get medical help right away if you have any very serious side effects, including: fainting, seizure, slow/shallow breathing, severe drowsiness/difficulty waking up.
This medication may increase serotonin and rarely cause a very serious condition called serotonin syndrome/toxicity. The risk increases if you are also taking other drugs that increase serotonin, so tell your doctor or pharmacist of all the drugs you take (see Drug Interactions section). Get medical help right away if you develop some of the following symptoms: fast heartbeat, hallucinations, loss of coordination, severe dizziness, severe nausea/vomiting/diarrhea, twitching muscles, unexplained fever, unusual agitation/restlessness.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.