Wednesday, October 13, 2010

Extended-Release Inectable dosage form of Naltrexone gets US FDA approval for treating patients with opioid-dependance

Extended-Release Injectable dosage form of Naltrexone gets US FDA approval for treating patients with opioid-dependence

The United States F D A has approved Injectable dosage form of naltrexone (Vivitrol) for treating patients having opioid dependence , for those who have undergone detoxification treatment to treat and prevent relapse of opoid dependence.
Vivitrol is an extended-release formulation containing naltrexone as an active ingredient It is an intramuscular injection which is administered once a month.

Naltrexone is the N-cyclopropylmethyl derivative of oxymorphone.Naltrexone closely resemble to morphine molecule , in morphine molecule there is a methyl group over tertiary amine that is replaced with cyclopropylemethyl group, because of this Naltrexone has capability to reduce the addiction or dependence of morphine by occupying morphine/opoiod receptors. Naltrexone works by blocking opioid receptors in the brain. It blocks the effects of drugs like morphine, heroin, and other opioids.

In opioid dependence detoxification patients are required to take daily dose of oral dosage form of Naltrexone for 12 months to prevent relapse of opioid dependence, and there are chances that patient may skip his dose one or the other time which makes him prone for reoccurrence of opioid dependence. The Vivitrol (Naltrexone) an extended-release formulation which requires to be administered once in a month intramuscularly will be able to make free from daily schedule of oral dose, and can over come disadvantages of oral dosage form Naltrexone
In 2006 Vivitrol is also approved by US FDA to for treatment of alcohol dependence.
Clinical Trial
Safety and efficacy study for Vivitrol was done for six months, it was observed that patients on Vivitrol treatment who were completed detoxification were found to be no longer physically dependent on opioids compared to placebo . About 36 % of the patients treated with Vivitrol were able to stay away from illicit drugs for the full six months of study without using drugs, compared with 23 percent in the placebo group.
It is required that patients must be free from any presence of opioid drugs in their system when they start taking Vivitrol ; otherwise, it is likely to that they may show withdrawal symptoms from the opioids. At the time when next dose schedule for Vivitrol is due patients may become more sensitive to opioids as well. It is likely that patients when miss a dose or after treatment with Vivitrol has ended, patients can accidentally overdose if they restart opioid use.
Side effects: of Vivitrol. dizziness, vomiting, nausea, tiredness, headache , decreased appetite, painful joints, and muscle cramps.
Other serious side effects included reactions at the site of the injection, which can be severe and may require surgical intervention, liver damage, allergic reactions such as hives, rashes, swelling of the face, pneumonia, depressed mood, suicide, suicidal thoughts, and suicidal behavior.

Vivitrol must be administered by a physician as an intramuscular injection, a special administration needles are also provided with Vivitrol and it must not be injected using any other needle

Vivitrol is manufactured by Alkermes, Inc. a pharmaceutical company based in USA Waltham, Massachusetts. They are in to the business of developing and marketing extended release drugs so that the drugs remain in body over a prolonged and desired period of time period.

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