Tuesday, November 24, 2009

Buprenorphine Detox and Treatment

Close to a million individuals in US are addicted to opioids and yet less than 20% receive any treatment for their addiction. The best management for these chronic addicts is medical treatment which decreases their addiction and improves their social status in society. For the past 4 decades, methadone has been the treatment of choice for the treatment of drug addicts. However, all methadone programs have long waiting lists, have rigid admission criteria and the majority of methadone programs are only found in large urban cities. Current data indicate that buprenorphine, which is a partial opioid receptor agonist, may also be effective for treatment of opioid addiction.

The Drug Addiction Treatment Act of 2000 allowed physicians to provide office-based treatment for opioid addiction. This Federal Legislation allowed physicians to prescribe Schedule III, IV, or V "narcotic" medications that were approved by the U.S. Food and Drug Administration for patients with opioid addiction. In 2002, the FDA approved buprenorphine and combination ofbuprenorphine/naloxone (Suboxone) to manage opioid dependence.

Buprenorphine (Suboxone)

Buprenorphine, is an opioid drug with partial agonist and antagonist activity. Buprenorphine was first marketed in the 1980s as an analgesic, yet today it is primarily used for the treatment of opioid addiction. It has a longer duration of action than morphine, and sublingual administration offer an analgesic effect which lasts 6 to 8 hours. Because the drug can not be reversed by naloxone, it is not recommended for pain control.

When used for opioid dependence, buprenorphine remains effective in the body for up to 48 hours, decreases the tendency for withdrawal syhimptoms and counteracts the effects of concomitant opioids that may be taken by the patient.

Side Effects

Buprenorphine does have some side effects and these include nausea, vomiting, drowsiness, dizziness, headache, itch, dry mouth, meiosis, orthostatic hypotension, dfficulty with ejaculation, decreased libido, urinary retention, and constipation. Rare cases of liver necrosis and hepatitis with jaundice have been reported with the use of buprenorphine. For those who receive buprenorphine, the liver function is regular monitored. The most severe and serious adverse reaction associated with buprenorphine use is respiratory depression which can be fatal. This is particularly problematic with buprenorphine because unlike morphine, there is no effective antidote.

Additionally, concurrent use of buprenorphine and CNS depressants (such as alcohol or benzodiazepines) is contraindicated as it may lead to fatal respiratory depression.

Dependence

As with other opioids, buprenorphine can produce both physical and psychological dependence. However, unlike other opioids, users of buprenorphine rarely develop a tolerance to the drug. Maintenance dosages can remain at the same moderate level and in many cases even lowered, without causing withdrawal symptoms.

Treatment of Opioid Dependence

Sublingual buprenorphine preparations are often used in the management of opioid dependence (such as heroin, oxycodone, hydrocodone,morphine). The use of buprenorphine replacement therapy in the management of opioid dependence is regulated and monitored. In the United States, a special federal waiver is required to prescribe Subutex on an outpatient basis. Each Federally approved physician is allowed to manage only 30 patients on buprenorphine for opioid addiction as outpatients.

Withdrawal Symptoms

The partial agonist/antagonist activity of buprenorphine means that it may precipitate withdrawal symptoms when an opioid-dependent patient is commenced on the drug soon after the use of another opioid drug. Patients are advised to wait between 24 and 36 hours after their last use of short-acting opioids (such as heroin or oxycodone) before beginning treatment with buprenorphine. Those who are on
methadone should only be treated with buprenorphine once withdrawal symptoms are present. Beginning any earlier may result in extreme cases of opioid withdrawal.

BUPRENORPHINE vs. METHADONE

Buprenorphine and methadone are both used for short-term and long-term opioid maintenance therapy. Each agent has its relative advantages and disadvantages.

Buprenorphine sublingual tablets have a long duration of action which may allow dosing every two days, compared with the daily dosing required with methadone. In the United States, following initial management, a patient may be prescribed one month supply for self-administration on the condition that the patient receives other dependence therapy.

Buprenorphine may have a lower dependence-liability than methadone. Buprenorphine treatment typically lasts several months (though sometimes for only a few weeks or up to two or three years), as opposed to an indefinite, often life-long methadone regimen.

Buprenorphine itself appears to have less-severe withdrawal effects than methadone, and thus it is easier to discontinue use. Buprenorphine, as a partial μ-opioid receptor agonist, has been claimed to have a less euphoric effect compared to the full agonist methadone, and was therefore predicted to be less likely to be diverted to the black market.

DETOX AND REHABILITATION

The practice of using buprenorphine in an inpatient rehabilitation setting is increasing rapidly. These rehabilitation programs consist of "detox" and "treatment" phases. The detoxification phase consists of medically-supervised withdrawal from the drug of dependency, sometimes aided by the use of medications such as buprenorphine and valium.

Buprenorphine is sometimes used only during the detox protocol with the purpose of reducing the patient's use of mood-altering substances. It considerably reduces opioid
withdrawal symptoms that are normally experienced by opioid-dependent patients on cessation of those opioids, including diarrhea, vomiting, fever, chills, cold sweats, muscle and bone aches, muscle cramps and spasms, restless legs, agitation, gooseflesh, insomnia, nausea, watery eyes, runny nose and post-nasal drip, nightmares, etc. The buprenorphine detox protocol usually lasts about 7-10 days, provided that the patient does not need to be detoxed from any additional substances such as barbiturates, benzodiazepines, or alcohol.

Dosing

During detoxification Buprenorphine is administered on a daily basis. Generally, the patient receives a single dose each day to ensure a consistent active level of the medication remains in the patient's central nervous system. Typically, the initial daily dose totals around 8-16mg. The dosage is slowly tapered each day and the medication is usually stopped 36-48 hours prior to the end of the detox program, with the patient's vitals monitored up until discharge from the detox program.

Summary

Buprenorphine is an alternative and not a replacement agent for methadone in patients with opioid dependence for opioid agonist therapy in patients with opioid dependence. Buprenorphine is viable in the primary care setting, which enhances treatment accessibility, and may be a better initial choice for patients at greater risk of respiratory depression, such as elderly patients and those taking benzodiazepines. Choice of first-line treatment will depend on patient preference, expectations, past treatment experiences and side effect profile as well as availability, dispensing regulations, cost and government reimbursement schedules. However, regardless of choice of methadone or buprenorphine, patients with opioid dependence do best in a comprehensive program involving opioid agonist treatment, counseling and support.

No comments:

Post a Comment