Therapeutically morphine

In the case of heroin, the indicator used is nonexclusive of heroin consumption, as it is also excreted to a high extent after administration of therapeutic morphine and in minor proportions after use of other opioids, such as codeine, pholcodine, and ethylmorphine. In order to obtain comparable results to previous studies [25, 31], an average medical administration of morphine of 10 mg/capita/year [45] and an excretion rate of 85% of morphine after therapeutic use [25, 31] were considered in the calculations. 

Morphine is the most abundant of the opium alkaloids. It constitutes as much as 15 percent of the plant extract. Morphine has been used as a medicine and narcotic for thousands of years. Therapeutically, morphine has three principal uses as an analgesic for the relief of acute and chronic pain, as a respiratory depressant, and as an antidiarrheal agent. The analgesic properties are morphine s most important clinical use. 

Morphine has certain undesirable side effects. Among these are respiratory depression, nausea, and vomiting, depression of the cough reflex, cardiovascular depression and hypotension, smooth muscle contraction (constipation), and histamine release (93). Morphine s onset of action, duration, and low therapeutic indices have prompted a search for a more effective opiate iv anesthetic. Extreme simplification of the complex morphine molecule has resulted in anilido —piperidines, the fentanyl class of extremely potent opiate iv anesthetics (118,119). 

Administration of sufficient doses of an opioid antagonist after only a single therapeutic dose of morphine results in withdrawal phenomena (Bickel et al. 1987 Heishman et al. 1989 Jones 1979). Some degree of physical dependence... 

There are a number of side-effects of opiates that are due to their actions on opiate receptors outside the central nervous system. Opiates constrict the pupils by acting on the oculomotor nucleus and cause constipation by activating a maintained contraction of the smooth muscle of the gut which reduces motility. This diminished propulsion coupled with opiates reducing secretion in the gut underlie the anti-diarrhoeal effect. Opiates contract sphincters throughout the gastrointestinal tract. Although these effects are predominantly peripheral in origin there are central contributions as well. Morphine can also release histamine from mast cells and this can produce irritation and broncho-spasm in extreme cases. Opiates have minimal cardiovascular effects at therapeutic doses. 

Drugs with no therapeutic use (cannabis, LSD) and so are not prescribed Drugs with medical use — heroin and morphine for pain relief, amphetamine for narcolepsy and cocaine... 

Some implantation devices have extended well beyond the classic diffusional systems and have included not only bioerodible devices, but also implantable therapeutic systems that can be activated. There are devices activated by change in osmotic pressure to deliver insulin [225], morphine release trigger by vapor pressure [226], and pellets activated by magnetism... 

Rectal Administration. The administration of drugs by a solid rectal dosage form (i.e., suppositories) results in a wide variability in the rate and extent of absorption in children [79]. This fact, coupled with the inflexibility of a fixed dose, makes this a route that should not be promoted for pediatric patients. At least one death involving a 7-month-old infant can be directly attributed to the use of solid rectal dosage form of a therapeutic dose of morphine [80]. 

The biochemistry and pharmacology of 5-HT receptors have been reviewed [74], therapeutic implications presented [75, 76], and functional classification proposed [77], Recently, the neuroanatomy, physiology and pharmacology of 5-HT, receptors have been reviewed [78]. It is evident that major advances have been made since the Gaddum and Picarelli proposal to subdivide 5-HT receptors into D (dibenzyline sensitive) and M (morphine sensitive) types [79]. Subsequently, the D and M receptors have been identified as 5-HT2 and 5-HT, type, respectively. 

Axelrod, J. (1955) The enzymatic conversion of codeine to morphine. Journal of Pharmacology and Experimental Therapeutics, 115 (3), 259-267. 

Opioid levels in the brain are significant within seconds to minutes after injection. As mentioned before, heroin is more lipid soluble than morphine, so a greater amount penetrates the brain. Lipid solubility and ionization are the predominant factors that determine the distribution of opioids (Mather 1987). At therapeutic concentrations, about one-third of morphine is bound to protein in the blood. 

Finally, aside from strictly illegal substances and their metabolites, psychoactive substances or dmgs of abuse may also include active ingredients from pharmaceutical products with legal therapeutic uses such as morphine. 

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