Fentanyl is metabolized mainly via the human cytochrome P450 3A4 isoenzyme system (CYP3A4); therefore potential interactions may occur when ABSTRAL is given concurrently with agents that affect CYP3A4 activity. The concomitant use of ABSTRAL with CYP3A4 inhibitors (e.g., indinavir, nelfinavir, ritonavir, clarithromycin, itraconazole, ketoconazole, nefazodone, saquinavir, telithromycin, aprepitant, diltiazem, erythromycin, fluconazole, grapefruit juice, verapamil, or cimetidine) may result in a potentially dangerous increase in fentanyl plasma concentrations, which could increase or prolong adverse drug effects and may cause potentially fatal respiratory depression. Patients receiving ABSTRAL who begin therapy with, or increase the dose of, CYP3A4 inhibitors need to be carefully monitored for signs of opioid toxicity over an extended period of time. Increase dosage conservatively. The concomitant use of ABSTRAL with CYP3A4 inducers (e.g., barbiturates, carbamazepine, efavirenz, glucocorticoids, modafinil, nevirapine, oxcarbazepine, phenobarbital, phenytoin, pioglitazone, rifabutin, rifampin, St. John's wort, or troglitazone) may result in a decrease in fentanyl plasma concentrations, which could decrease the efficacy of ABSTRAL. Patients receiving ABSTRAL who stop therapy with, or decrease the dose of, CYP3A4 inducers need to be monitored for signs of increased ABSTRAL activity and the dose of ABSTRAL must be adjusted accordingly. Drug Abuse And Dependence Controlled Substance ABSTRAL contains fentanyl, a Schedule II substance. Schedule II opioid substances such as fentanyl, hydromorphone, methadone, morphine, oxycodone, and oxymorphone have a high potential for abuse and addiction. ABSTRAL is also subject to misuse and criminal diversion. Abuse And Addiction Manage the handling of ABSTRAL to minimize the risk of misuse, including the restriction of access and accounting procedures as appropriate to the clinical setting and as required by law [see HOW SUPPLIED/Storage and Handling]. Concerns about abuse, addiction, and diversion must not prevent the proper management of pain. However, all patients treated with opioids require careful monitoring for signs of abuse and addiction, because use of opioid analgesic products carries the risk of addiction even under appropriate medical use. Addiction is a primary, chronic, neurobiologic disease, with genetic, psychosocial, and environmental factors influencing its development and manifestations. It is characterized by behaviors that include one or more of the following: impaired control over drug use, compulsive use, continued use despite harm, and craving. Drug addiction is a treatable disease, utilizing a multidisciplinary approach, but relapse is common. “Drug-seeking” behavior is very common in addicts and drug abusers. Abuse and addiction are separate and distinct from physical dependence and tolerance. Be aware that addiction may not be accompanied by concurrent tolerance and symptoms of physical dependence in all addicts. In addition, abuse of opioids can occur in the absence of addiction and is characterized by misuse for non-medical purposes, often in combination with other psychoactive substances. Since ABSTRAL may be diverted for nonmedical use, careful record keeping of prescribing information, including quantity, frequency, and renewal requests is strongly advised. Proper patient assessment, safe prescribing practices, periodic re-evaluation of therapy, and proper dispensing and storage are appropriate measures that help to limit abuse of opioid drugs. Contact your State Professional Licensing Board, or State Controlled Substances Authority for information on how to prevent and detect abuse or diversion of this product. Dependence Physical dependence is not ordinarily a concern in the treatment of patients with chronic cancer pain, and fear of tolerance and physical dependence must not deter using opiate doses that adequately relieve the pain. Guide the administration of Abstral by the response of the patient. Opioid analgesics may cause physical dependence that can result in withdrawal symptoms in patients who abruptly discontinue the drug. Withdrawal also may be precipitated through the administration of drugs with opioid antagonist activity (e.g., naloxone, nalmefene) or mixed agonist/antagonist analgesics (pentazocine, butorphanol, buprenorphine, nalbuphine). Physical dependence usually does not occur to a clinically significant degree until after several weeks of continued opioid usage. Tolerance, in which increasingly larger doses are required in order to produce the same degree of analgesia, is initially manifested by a shortened duration of analgesic effect, and subsequently, by decreases in the intensity of analgesia. Last reviewed on RxList: 11/12/2014
This monograph has been modified to include the generic and brand name in many instances.