In general, buprenorphine treatment should start at least 6 to 12 hours after the last heroin dose or 24 to 72 hours after the last dose of long-acting opioids. 187 Initiating buprenorphine at a lower dose can reduce the risk of precipitated withdrawal. An initial dose of 2 to 4mg is recommended, followed by observation for signs of precipitated withdrawal. If withdrawal symptoms are not experienced within 60 to 90 minutes, additional doses can be given in increments of 2 to 8mg as needed. 187 Buprenorphine has a lower risk of overdose when compared with full agonist opioids; respiratory depression is limited with a ceiling effect at higher doses. Caution is still advised, particularly when combining buprenorphine with alcohol, hypnotics, or anxiolytics, as respiratory depressive effects can be enhanced by these substances. Caution is also advised when using in patients with hepatic impairment. Buprenorphine is generally well-tolerated, but headache, anxiety, constipation, fluid retention and sleep disturbances have been reported. 187 Unlike methadone, buprenorphine can be prescribed on an outpatient basis, with some restrictions outlined in the Drug Addiction Treatment Act of 2000 (DATA 2000). Through this act, providers can apply for waivers to prescribe certain controlled substances, such as buprenorphine, from their office settings rather than from opioid treatment programs, in order to expand access to medications to treat substance use disorders. A clinician must obtain a DATA 2000 waiver, which allows trained physicians to prescribe CIII-V medications to treat opioid use disorder in an office or clinic. The physician must have a valid medical license, a DEA number, and one additional criteria such as addiction certification, board certification in addiction medicine, or other additional training. Both buprenorphine and buprenorphine/naloxone may be prescribed with a DATA 2000 waiver. However, the DATA 2000 act limits the number of patients who can be treated at one time. The 2018 Substance Use-Disorder Prevention that Promotes Opioid Recovery and Treatment (SUPPORT) for Patients and Communities Act expanded DATA 2000 to include nurse practitioners and physician assistants to increase access to treatment. More information on training and registration is available at buprenorphine.samhsa. gov. 187 Prescribers will receive a DATA 2000 waiver identification number that begins with X. Both their DEA number and DATA 2000 waiver number must be provided on prescriptions. The “Buprenorphine Pharmacy Lookup” tool on the SAMHSA website can be used to verify a physician’s DATA waiver and the number of patients they may treat at one time. 188 Since buprenorphine can be prescribed on an outpatient basis, some additional steps are recommended to decrease diversion. The American Society of Addiction Medicine recommends frequent office visits to obtain refills, observed dosing, and pill counts, as well as urine drug screens and frequent access to state prescription drug monitoring programs. Like methadone, buprenorphine should be used in
conjunction with psychosocial treatment. There are no well-established recommendations for length of therapy. 187 Methadone Once the mainstay of opioid withdrawal treatment, methadone is less commonly used for the treatment of withdrawal symptoms. It acts as an agonist at the opioid receptor to produce its effect, essentially acting as a replacement drug for opioids of abuse. Its slow onset of action creates less of a rewarding effect compared with other opioids, while preventing symptoms of withdrawal. Methadone is a schedule II controlled substance and can only be administered for medically supervised withdrawal at federally designated outpatient treatment programs or inpatient hospital settings. This is because if taken in high doses, methadone can cause respiratory depression and lead to an overdose, so administering the medication in a controlled environment is necessary for the treatment of withdrawal. 187 Methadone has several unique qualities that complicate its use. It has a long half-life, which means the drug will accumulate in the body faster than it is eliminated over a 24-hour period. While this becomes less of an issue over time as drug levels reach steady state, the long half-life requires cautious dosing in the beginning of treatment to prevent overdosing. The risk of overdose is high in the first two weeks of methadone treatment, so federal law dictates that the first dose should not exceed 30mg, and the total daily dose for the first day of medically supervised withdrawal should not exceed 40mg. In general, doses should not be tapered daily – increasing at intervals of 5mg every 2 to 3 days, or 10mg every 5 days, are recommended to reduce the risk of overdose. When tapering on to methadone, patients should be carefully monitored for signs of overdose. it is important to remember that due to the long half-life, it takes time to realize the full benefits of treatment, and patients can still feel opioid withdrawal symptoms during the first few days of treatment. 187 Maintenance doses of methadone can range from 30 to 120mg per day. Studies have shown that higher doses, such as between 80 to 100mg per day, are associated with better outcomes than lower doses. It is thought that these dosing levels create enough opioid tolerance to minimize the euphoria felt if patients decide to take additional opioids on their own. 187 Methadone has significant adverse effects on the heart. It can prolong the QTc interval, causing potentially fatal arrhythmias such as torsades de pointes. It should not be used in patients with a pre-existing long QTc interval. It should also be used cautiously in patients with an increased risk of hypokalemia, hypomagnesemia, hypocalcemia, and bradycardia, as these can increase the risk of prolonging the QTc interval. Methadone should be avoided in combination with other medications that can prolong the QTc interval such as antipsychotics amongst others. In patients with risk factors for QT prolongation, a baseline ECG is suggested before starting methadone treatment.
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Book Code: CA23CME
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