Could This Drug Replace Methadone and Buprenorphine in Opioid Dependent Patients?
Opioid dependence is one of the most severe drug dependencies and is currently growing in many countries around the world, with the increased availability of illicit supplies of clinically relevant medicines like Fentanyl and Oxycodone becoming used as party drugs and the increase in the number of prescriptions issued to patients for long term pain therapy who tend become very dependent on them.
Naltrexone is a medication that completely blocks the subjective and other effects of opioids and, when administered to detoxified opioid addicts and taken as directed, prevents relapse and helps maintain abstinence. The major problem with naltrexone had been poor compliance, particularly in countries in which there is a treatment alternative based on substitution of illicit opioids such as heroin with orally administered opioid agonists (methadone) or partial agonist/antagonists (buprenorphine)
In Russia, substitution therapy is forbidden by law, and naltrexone is the only available pharmacotherapy for heroin dependence. Due to the lack of alternatives to naltrexone , naltrexone is more effective for relapse prevention and abstinence stabilization in Russia than in Western countries. Long-acting, sustained-release formulations (injectable and implantable) seem particularly effective compared with oral formulations
Naltrexone is a perfect antagonist for treating heroin dependence, as 50 mg (one tablet) blocks the subjective effects of heroin for 24 to 36 h; it is easy to administer (one tablet per day or two tablets every other day), safe (no common serious adverse events if used in recommended doses)
Vivitrol, Released Prisoners and Inplants
In 2010 though a new formulation was of Naltrexone introduced to the US Market called Vivitrol. It’s been called a magic shot or miracle drug for opioid addiction even though it was originally indicated for alcohol dependency.
Vivitrol, is a sustained release formulation of Naltrexone, given by intramuscular injection only once a month and it appears to cut the risk of relapse in half, at least while people are still getting the injection.
A study was conducted in an especially vulnerable group: opioid addicts who had recently been released from prison to test the efficacy of Vivitrol and studies prior to this one show that about three-quarters of jailed addicts will relapse within 3 months of their release. Even when they were referred to medication-assisted treatments with the drugs methadone or buprenorphine (Suboxone) — treatments that have been proven to help people stay clean — one study found only 8% followed through and got help.
The new study, which was published in the New England Journal of Medicine, followed about 300 people, mostly middle-aged men, who had recently been released from prison. Nearly 90% of them were addicted to heroin.
Half the group was randomly chosen to get the usual treatment, which consisted of referrals to relapse prevention services, counseling, and prescriptions for methadone or Suboxone — pills that can prevent a relapse. The other half got counseling and a monthly injection of Vivitrol.
After 6 months, only 43% of the people in the Vivitrol group had relapsed compared to 64% of the group that got the usual treatment. Vivitrol cut the risk that a person would relapse by almost half for the 6 months people were taking the drug.
What’s more, even a year after stopping the treatment, there were no overdoses in the Vivitrol group, but there were seven in the group that got the usual treatment.
Vivitrol, isn’t without side effects. And it’s expensive. Although the drug has been FDA approved to treat opioid addiction since 2010, it hasn’t been widely used due to its impressive price tag.There’s sticker shock when you tell people it costs $1,200 per month and not covered on most insurance plans.
The real benefit of the drug is compliance. With methadone, people have to travel to a clinic to get a daily dose until they’re considered stable enough to do it on their own, or they have to remember to take a daily Suboxone pill.
Naltrexone in another formulation is also being investigated, it is an implant form of the medication and it went on trial in Ireland last year .The ‘bar’ is placed into the lower abdomen during a minor surgical procedure with the patient under local anaesthetic. Unlike tablets or injections of Naltrexone, the effects of the implant last for up to three months before it needs to be replaced. The implant is fitted by the One Step Clinic from its base in Dublin City University , but a clinic has also been set up at Cork University Hospital.
But any patient seeking to have a Naltrexone bar fitted would already have had to undergone a detox programme and be tested on the day of any procedure to ensure there are no drugs in their system.
At present the model is that the patient pays, with the cost of each implant coming in at €950. a client was likely to have to use the implants for between 18 months and two years to minimise the chances of a relapse.
Treating drug dependencies is a very difficult business, and more often than not, in the current system , a lot of addiction enabling factors are never removed before a patient is started on methadone therapy in clinics or in pharmacies with taxpayers footing the bill. The inherent pharmacological need for the patient to be without any other opioids in their system before they start on either of the two versions of naltrexone mentioned above,coupled with the inability to reverse the dose or skip a dose, for a long period of time, may present a situation where will-power may not be as big a factor as other therapies , there by yielding better results, and costing a lot less in the long run.
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