Opiate pain relievers addiction

The risk of becoming addicted to an opiate pain reliever increases the longer the drug is taken (over a period of weeks or... 

Although not everyone becomes severely addicted to opiate pain relievers, there are certain people for whom the drugs become irresistible. The addiction may drive these ordinarily upstanding individuals to criminal behavior to satisfy their craving and compulsive need for these medications. 

As seen in Figure 3.7, the most widely abused opiate pain relievers are Darvocet , Darvon , and Tylenol with codeine , followed by Vicodin, Lortab , and Lorcet . Methadone is the least addicting of the opiate pain relievers and stays in the body the longest. Because of this, methadone is often used as a substitute for morphine, heroin, and other more addictive opiates to wean people off the drug to which they are addicted. 

Addiction occurs after a variable period of time. Although it usually requires more than 2 weeks of repeated use of a narcotic, addiction may develop in a few days and, in some unstable personalities, after only a few doses. Physical dependence has been shown to develop within 2 d by the use of nalorphine. Great care should therefore be exercised not to prescribe a narcotic for a longer period of time than is absolutely necessary, and to avoid clocklike regularity in its administration. The continued employment of an opiate to relieve pain in terminal illnesses or neoplastic diseases does not come under the scope of the present discussion, and addiction under such circumstances is often unavoidable. 

Doctors are most likely to prescribe morphine or other opiates when pain is severe and expected to be short-lasting (a few days to a week), such as after injury or major surgery. This is because short-term use of opiates is less likely to lead to tolerance (loss of potency with repeated use of the drug) and dependence (addiction). However, the problem becomes more complex when the severity of the pain requires the use of pain-relieving medication for more than a few weeks, because this is when tolerance and addiction to opiates tend to develop (see the section on Opiate Addiction on page 48). 

Pharmacologists have been unable to come up with analgesics (pain relievers) ot medium strength to fill the gap between aspirin and morphine. They have given us several derivatives of opiates that they claimed were more powerful than aspirin but safer and less addicting than morphine. If these drugs are effective at controlling pain, however, they always turn out to be attractive to opiate addicts and are likely to cause dependence. 

Use of the opium poppy (Papaver somniferum) to ameliorate pain dates back thousands of years, and the active metabolite morphine (2) was isolated first from its extracts in 1806 followed by codeine (53) in 1832 (27, 28). Morphine and its derivatives are agonists of opiate receptors in the central nervous system and are some of the most effective pain relievers known and prescribed for postoperative pain. Morphine and codeine differ by substitution by methyl ether. Unfortunately, addictive properties of these compounds limit their use. Efforts have been made to reduce the addictive properties of morphine, which resulted in a semisynthetic derivative buprenorphine (54) (29). This compound is 25 to 50 times more potent than morphine with lower addictive potential and has been indicated for use by morphine addicts. 

Meperidine (Schedule II) is a synthetic analgesic with opiate activity. It has 10-20% of the potency of morphine with all of the addictive side effects. It has a rapid onset of action and duration which makes its useful for relieving the pain associated with labor or as a preanesthetic before surgery. Its biotransformation produces normeperidine which has been associated with seizures. It was a botched clandestine attempt to synthesize a meperidine modification which produced the toxic drug that induced parkinson-type destruction of DA neurons in its users. 

Narcotics (opiates and opioids) are natural, semisynthetic, and synthetic derivatives of the opium poppy. Drugs such as morphine, codeine, heroin, methadone, Darvon, and Percodan fall into this category. They are all depressants, but they are also potent painkillers, and except for heroin (which is illegal) they are prescribed to relieve pain and to control coughing and diarrhea. But because of their pleasurable effects and addictive properties, they can cause problems when taken for nonmedical reasons. Most nonmedical users take these drugs to experience euphoria, to avoid pain, and to relieve withdrawal symptoms. —... 

Pentazocin was the first clinically approved drug that was both an agonist and antagonist of opiate receptors that would relieve pain. The antagonist action was to prevent addiction. It has been used to treat heroin addicts. 

Billions of dollars are invested every year to develop drugs that affect behavior. Penta-zocin was the first clinically approved mixed agonist/antagonist that would relieve pain. For decades, this long-acting opiate agonist has also been given to treat heroin addicts. 

The discovery of a naturally occurring peptide called endorphin in the brain led to a search for pain-killing drugs that would be less addictive than morphine or other opiates used to relieve pain. The new drugs would be as natural as endorphin, and they could provide new insight into the molecular processes of addiction. 

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