Opiates subjective effects

Benzodiazepine abuse is different from other substance abuse disorders (opiates, amphetamines, and nicotine) because benzodiazepines cause much less euphoria and do not activate the classic reward systems that are activated with other substances (mainly the mesolimbic and mesocortical dopaminergic projections). In fact, most people do not find the subjective effects of benzodiazepines pleasant beyond their therapeutic anxiolytic or sleep-inducing effects. Therefore, abuse of benzodiazepines is usually secondary to other substance-abuse disorders, with the benzodiazepine being taken for relief from symptoms induced by the use of another drug. As potential drugs of abuse, short-acting benzodiazepines seem to be preferred among addicts because of the rapidity of their onset of action (aiprazoiam, fiunitrazepam, and iorazepam). 

The most useful modality for dealing with the societal aspects of opiate abuse (as well as some of the medical and personal aspects) has been methadone maintenance. In consideration of the pharmacology of opiate dependence 4,17,45,58,87,88,131,140,172,185 Dole and Nyswander 51 proposed that maintenance of opiate addicts on relatively large doses of oral methadone would inhibit drug seeking behavior, "block" the subjective effects of parenteral heroin injection because of the tolerance induced, break the needle habit because of lack of reinforcement by this route, and make the addict more available for psychiatric treatment and rehabilitation, breaking the cycle of crime and punishment. Methadone maintenance has been... 

The effects of corticosteroids, cyclooxygenase blockers, leukotriene blockers, PAF antagonists, anti-TNF antibodies, oxygen radical scavengers, opiate antagonists, antihistamines, and calcium channel blockers in endotoxic shock were reviewed in 1990 (H17). In this section studies on this subject that have been published during the last few years are summarized. 

Acute physiological responses to opiate administration occur rapidly and include constricted pupils, decreased pulse rate, reduced body temperature, slowed respiration rate and impaired reflexes. In addition, there is a marked slowing of the digestive system through an altering of the tonus and motility of the stomach and intestines, allowing for greater water absorption. This last effect is not subject to tolerance, and constipation is a common side effect even for chronic users. Indeed, some report that this is the worst side effect of opiate use. 

In Table 1.3 I have included the areas of physical and psychological health, which often do not feature in reviews. Methadone has significant adverse effects, as discussed below, and by no means do all patients report subjective improvements in health on the drug, as opposed to when taking street heroin or other opiates. However, if methadone treatment is adhered to, there is normalization of various circadian rhythms and endocrine effects... 

Most opiates are subject to significant first-pass metabolism in the liver, and for this reason, parenteral administration is more effective than per os, although the latter is often of longer duration.07 418 At therapeutic plasma levels, about one-third of the drug is bound to plasma protein. Codeine, which has the morphine 3-OH masked, behaves rather differently, and because of a lower first-pass loss, has a significantly greater po efficacy (about two thirds the parental effect). 

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