Wedgewood compounds 1gm Naltrexone pellets
 Naltrexone
is an opiate antagonist that reduces the euphoric effect of opiates
and alcohol. It was approved by the FDA in 1984 for the treatment
of opiate addiction, in 1994 for the treatment of alcoholism and
in 2006 as a depot injectable. Naltrexone and its active metabolite,
6- -naltrexol, are inverse agonists of -and - opiod receptors, and
to a lesser extent at -opioid receptors.[1]
They serve to block the effects of endorphins, endogenous opioid
peptides in the brain, thus indirectly attenuating the dopaminergic
reinforcement/reward system activity following alcohol intake.[2]
The endogenous opioid system is involved in the reinforcement of
alcohol use and naltrexone, by blocking the pleasurable effects
or 'high' of alcohol, presumably helps in the treatment of alcoholism.[3,
4] As a consequence, naltrexone reduces the quantity and
frequency of drinking among alcoholics who relapse.[5-7]
A systematic meta-analysis of 24 placebo-controlled trials presented
in 32 papers with a total of 2861 patients treated concluded that
naltrexone produced a consistent decrease in relapse rate to heavy
drinking and in drinking frequency, although it did not appear to
enhance absolute abstinence.[8]
Naltrexone is rapidly absorbed, with peak blood levels achieved
approximately one hour following oral administration.[9] It is primarily
metabolized by the liver, and converted to 6- -naltrexol, which
has a plasma half life of 10 hours. Approximately 20 percent of
the active metabolite is bound to plasma protein and distributed
widely, with relatively high amounts found in the brain, fat, spleen,
heart, testes, kidney and urine.[9]
Naltrexone and its metabolite 6- -naltrexol, with less than 1 percent
of naltrexone, are excreted unchanged. Despite the relatively short
half lives of both compounds, the duration of naltrexone blockade
is much longer. Typically, an oral dose of 50mg naltrexone as been
shown to produce 80 percent inhibition of radiolabeled carfentanyl
binding for 72 hours.[10]
In alcohol dependence, naltrexone is considered a safe medication.
Control of liver values prior to initiation of treatment is recommended.
There has been some controversy regarding the use of opioid-receptor
antagonists, such as naltrexone, in the long-term management of
opioid dependence due to the effect of these agents in sensitizing
opioid receptors. Following therapy, the opioid receptors continue
to have increased sensitivity for a period during which the patient
is at increased risk of opioid overdose. This effect reinforces
the necessity of monitoring of therapy and provision of patient
support measures by medical practitioners.
References
- Shader, R.I., Antagonists, inverse agonists,
and protagonists. J Clin Psychopharmacol, 2003. 23(4):
p. 321-2.
- Benjamin, D., E.R. Grant, and L.A. Pohorecky,
Naltrexone reverses ethanol-induced dopamine release in the
nucleus accumbens in awake, freely moving rats. Brain Res,
1993. 621(1): p. 137-40.
- Volpicelli, J.R., et al., Effect of naltrexone
on alcohol "high" in alcoholics. Am J Psychiatry,
1995. 152(4): p. 613-5.
- O'Malley, S.S., et al., Experience of a
"slip" among alcoholics treated with naltrexone or placebo.
Am J Psychiatry, 1996. 153(2): p. 281-3.
- O'Malley, S.S., et al., Naltrexone and
coping skills therapy for alcohol dependence. A controlled study.
Arch Gen Psychiatry, 1992. 49(11): p. 881-7.
- Volpicelli, J.R., M.A. Davis, and J.E. Olgin,
Naltrexone blocks the post-shock increase of ethanol consumption.
Life Sci, 1986. 38(9): p. 841-7.
- Anton, R.F., et al., Naltrexone and cognitive
behavioral therapy for the treatment of outpatient alcoholics:
results of a placebo-controlled trial. Am J Psychiatry, 1999.
156(11): p. 1758-64.
- Srisurapanont, M. and N. Jarusuraisin, Naltrexone
for the treatment of alcoholism: a meta-analysis of randomized
controlled trials. Int J Neuropsychopharmacol, 2005. 8(2):
p. 267-80.
- Gonzalez, J.P. and R.N. Brogden, Naltrexone.
A review of its pharmacodynamic and pharmacokinetic properties
and therapeutic efficacy in the management of opioid dependence.
Drugs, 1988. 35(3): p. 192-213.
- Lee, M.C., et al., Duration of occupancy
of opiate receptors by naltrexone. J Nucl Med, 1988. 29(7):
p. 1207-11.
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actions, precautions, side effects, or interactions of the products
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Information and statements have not been evaluated by the Food and
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