Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0278080 (physical dependence)
 1,658 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tobacco is one of the major toxic agents in our civilization. The extent and severity of the current smoking epidemics are due to the use of industrial cigarettes: their smoke, less irritant than that of cigars and pipe, can be inhaled intensively with rapid absorption of all toxic compounds. Tobacco smoke is composed of a gas phase (CO2, CO, CNH, etc.) and a particle phase (a very fine aerosol) in which more than 4000 substances have been identified. The main toxic compounds in tobacco are Co, nicotine and tars. CO binds to haemoglobin to form COHb, a major factor of hypoxia and vascular accidents. Within a few seconds, nicotine reaches the brain where it binds to specific receptors, which explains its psycho-active effects (psychological dependence) and the induction of physical dependence. This dual dependence is responsible for the failures and relapses observed in attempted withdrawals. Furthermore, nicotine stimulates the sympathetic system with hypersecretion of catecholamines resulting in vascular complications. Tars contain carcinogenic substances, such as aromatic hydrocarbons, which exert local effects on the respiratory tract and systemic effects since they are absorbed by the lungs; this explains the remote neoplasias such as cancer of the bladder. Tars also contain irritant agents (acrolein, formaldehyde, etc.) and oxidative substances responsible for chronic bronchitis and emphysema. Thus, all organs and tissues can be damaged by the toxic compounds that are present in tobacco and, in particular, in tobacco smoke.
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PMID:[Toxicology of tobacco]. 823 55

The potentiation of morphine analgesia by dextromethorphan raises the issue of whether dextromethorphan also potentiates those actions of morphine that lead to abuse. Clinical pharmacology experiments indicated that dextromethorphan does not potentiate the euphorigenic and miotic actions of morphine. Morphine suppresses the dysphoric action of dextromethorphan. A second set of experiments indicated that dextromethorphan does not alter the response to naloxone-precipitated withdrawal. In a third set of experiments, dextromethorphan did not alter the morphine-induced depression in the slope of the increase in minute volume in response to breathing increased CO2. In contrast to potentiation of analgesia, dextromethorphan does not enhance the euphorigenic, physical dependence, and respiratory depressant actions of morphine. These findings indicate that dextromethorphan does not enhance the abuse potential of morphine and that the potentiation of analgesia appeared to be selective.
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PMID:Abuse potential of morphine/dextromethorphan combinations. 1068 36