Addictive potential

Hydromorphone [466-99-9] (31) and hydrocodone [125-29-1] (32) are isomers of morphine and codeine, respectively. Hydromorphone can be prepared by catalytic rearrangement of morphine (49) or by oxidation of the aliphatic hydroxyl group of dihydromorphine (50). Hydrocodone can be similarly prepared. As an antitussive, hydromorphone is several times more active than morphine and hydrocodone is slightly more active than codeine. Hydromorphone has a much higher addiction potential than hydrocodone. 

Dihydrocodeine [125-28-0] (33), introduced in Germany before 1930, and dihydrocodeinone enol acetate [466-90-0] (34) both have clinical activity and addiction potential comparable to codeine. 

More radical dissection of the morphine molecule was in progress concurrently with the work above. The chemistry of the series of analgesics that rely on an acyclic skeleton, the compounds related to methadone, is discussed earlier. Suffice it to say that this series of agents, with the possible exception of propoxyphene, seem to share abuse and addiction potential with their polycyclic counterparts. 

Addiction potential. The ability of a compound to elicit compulsive self-administration. 

Dezocine (30) represents a class of bridged aminotetralins possessing morphine-like analgesic properties. It appears to be roughly equivalent in potency and addiction potential to morphine. The molecule combines molecular features of precedent aminotetralins and benzomor-phans and its structure fits the classical Morphine Rule. The 1-enantiomer is the more active and the p-epimer (equatorial NHj) is the active diastereomer. 

Like the barbiturates, the miscellaneous drugp sedative or hypnotic effects diminish after approximately 2 weeks. Ffersons taking these dragp for periods longer than 2 weeks may have a tendency to increase the dose to produce the desired effects (eg, sleep, sedation). Physical and psychological dependence may occur, especially after prolonged use of high doses. However, their addictive potential appears to be less than that of the... 

The amphetaminesand anorexiants have abuse and addiction potential. Long-term use of amphetaminesfor obesity may result in tolerance to the drug and a tendency to increase the dose. Extreme psychological dependency may also occur. 

Another important animal model of the addictive potential of drugs is the conditioned place paradigm. When administered a drug that has rewarding/ pleasurable effects, animals will spend more time in the place associated with... 

Gaoni Y, Mechoulam R Isolation, structure, and partial synthesis of an active constituent of hashish. J Am Chem Soc 86 1646—1647, 1964 Gardner EL Addictive potential of cannabinoids the underlying neurobiology. Chem Phys Lipids 121 267-290, 2002... 

Lack of addiction potential—Although the medication affects certain chemicals in the brain, it is not addicting. 

Morphine and related opiates are known to suppress the cough reflex these compounds have thus been used extensively in antitussive preparations. Since this activity is not directly related to the analgesic potency, the ideal agent is one that has much reduced analgesic activity and thus, presumably, lower addiction potential. The weak analgesic codeine (4) is... 

Which factors influence the addiction potential for cocaine and amphetamine ... 

Given the low incidence of severe withdrawal symptoms and the modest effects on the mesolimbic dopamine (reward) system, most investigators have found that cannabis has a low abuse or addiction potential. However, it has been argued that if cannabis is a non-addictive substance, why is its use so widespread and why are there so many longterm and heavy users Finally, contrary to the evidence that cannabis can produce chronic tolerance, some regular users report that they require less drug to achieve the same high, or sensitisation (Chapter 3). Three possible explanations may account for this. First, chronic users may focus on the effects that they wish to achieve. Second, the... 

Outline the reasons for the high addiction potential of heroin. 

Despite public misconceptions, there is little firm evidence that the typical and atypical antidepressants produce dependence in clinical users. A review of 21 case reports of antidepressant addiction revealed that 12 were associated with tranylcypromine, although 8 of these 12 had a previous history of substance misuse (Haddad, 1999). Tranylcypromine s structural similarity to amphetamine may account for the significant number of reports of its addictive potential, but even here the term (mild) discontinuation reaction rather than withdrawal reaction should be used to allay any concerns patients might have (Haddad, 1999). 

The answer is c. (Hardman, pp 528-537.) Morphine is a pure agonist opioid drug with agonist activity toward all the opioid subtype receptor sites. In high doses, deaths associated with morphine are related to the depression of the respiratory center in the medulla. Morphine has a high addiction potential related to the activity of heroin or dihydromorphine. Codeine has a significantly lower addiction potential. 

Opiates and opioid derivatives delay the transit of intraluminal content or increase gut capacity, prolonging contact and absorption. The limitations of the opiates are addiction potential (a real concern with long-term use) and worsening of diarrhea in selected infectious diarrheas. 

Amphetamines should generally be avoided because of their powerful stimulant and addictive potential. 

Cannabis carries some potential for dependence and addiction. Compared to cocaine, heroin, alcohol, and nicotine, cannabis has lesser addictive potential and withdrawal effects, but some users do develop compulsive and maladaptive use patterns that require treatment (Taylor 1998). Individuals with underlying psychopathology or tendencies for substance abuse should be particularly leery of using cannabis in the interests of avoiding compulsive use patterns. 

The acid-base chemistry of nicotine is now well known and investigations have shown that nicotine in tobacco smoke or in smokeless tobacco prodncts can exist in pH-dependent protonated or nnprotonated free-base forms. In tobacco smoke, only the free-base form can volatilize readily from the smoke particnlate matter to the gas phase, with rapid deposition in the respiratory tract. Using volatility-based analytical measurements, the fraction of nicotine present as the free-base form can be quantitatively determined. For smokeless tobacco products, the situation differs because the tobacco is placed directly in the oral cavity. Hence, the pH of smokeless tobacco prodncts can be measured directly to yield information on the fraction of nicotine available in the nnprotonated free-base form. It is important to characterize the fraction of total nicotine in its conjugate acid-base states as this dramatically affects nicotine bioavailability, because the protonated form is hydrophilic while the nnprotonated free-base form is lipophilic and thus readily diffuses across membranes (Armitage and Turner 1970 Schievelbein et al. 1973). As drug delivery rate and addiction potential are linked (Henningfield and Keenan 1993), increases in delivery rate due to increased free-base levels affect the addiction potential. 

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