Opiates, medications derived either naturally or synthetically from the opium plant, bind to the opiate receptors in the body to block pain signals and induce euphoria. Opiates also act to depress the respiratory system and, in the case of overdose, can cause breathing to stop. An opiate antagonist is a medication that blocks the opiate receptors, therefore blocking the effects of the opiate. Antagonists such as naltrexone, naloxone or buprenorphine are often used to combat the overdose effects of an opiate or to help break an addiction to an opiate medication.
Naltrexone is either an oral or injection medication, and is commonly prescribed to help fight an addiction to either alcohol or opiate medications (legal or illegal). Naltrexone works by blocking the opiate receptors in the brain and blocking the feeling of euphoria felt when alcohol or an opiate is ingested. This in turn decreases the craving for the substance, according to the National Institutes of Health.
Naltrexone does not combat the withdrawal symptoms experienced when initially stopping the opiate medication. Naltrexone is therefore usually given once the initial dependence on the drug is over. Naltrexone alone will not cure the addiction, according to doctors at the Mayo Clinic, it is a part of an overall treatment program that includes counseling and support meetings.
Naloxone, most commonly known as Narcan, is an opiate antagonists that is used to treat the effects of an opiate drug overdose. Heroin overdose is one of the highest causes of preventable deaths in the United States, according to a study published in the January 2007 issue of the "Journal of Urban Health." Death from an overdose typically occurs within one to three hours after the overdose injection, which means there is plenty of time for medical intervention.
Naloxone, administered either by injection or inhaled through the nose, acts within minutes to reverse the effects of the opiate medication. In the case of a near fatal overdose, naloxone can restore breathing and blood pressure. Once naloxone is administered, withdrawal symptoms from the opiate medication will begin.
Buprenorphine is an opiate medication similar to morphine. Buprenorphine has a strong binding affinity for the opiate receptors in the body, and stays bound to the opiate receptors longer than other opiate medications, resulting in longer pain relief and a low level of physical dependence. These characteristics make buprenorphine a potent opiate antagonist that is often used to help treat opiate addiction.