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This paper aims to evaluate the anti-emetic efficacy of cannabinoids in cancer patients receiving chemotherapy using a systematic review of literature searched within electronic databases such as PUBMED, EMBASE, PSYCINFO, LILACS, and 'The Cochrane Collaboration Controlled Trials Register'. Studies chosen were randomized clinical trials comprising all publications of each database until December 2006. From 12 749 initially identified papers, 30 fulfilled the inclusion criteria for this review, with demonstration of superiority of the anti-emetic efficacy of cannabinoids compared with conventional drugs and placebo. The adverse effects were more intense and occurred more often among patients who used cannabinoids. Five meta-analyses were carried out: (1) dronabinol versus placebo [n=185; relative risk (RR)=0.47; confidence interval (CI)=0.19-1.16]; (2) Dronabinol versus neuroleptics [n=325; RR=0.67; CI=0.47-0.96; number needed to treat (NNT)=3.4]; (3) nabilone versus neuroleptics (n=277; RR=0.88; CI=0.72-1.08); (4) levonantradol versus neuroleptics (n=194; RR=0.94; CI=0.75-1.18); and (5) patients' preference for cannabis or other drugs (n=1138; RR=0.33; CI=0.24-0.44; NNT=1.8). The superiority of the anti-emetic efficacy of cannabinoids was demonstrated through meta-analysis.

Ritual use of ayahuasca, an amazonian Amerindian medicine turned sacrament in syncretic religions in Brazil, is rapidly growing around the world. Because of this internationalization, a comprehensive understanding of the pharmacological mechanisms of action of the brew and the neural correlates of the modified states of consciousness it induces is important. Employing a combination of electroencephalogram (EEG) recordings and quantification of ayahuasca's compounds and their metabolites in the systemic circulation we found ayahuasca to induce a biphasic effect in the brain. This effect was composed of reduced power in the alpha band (8–13 Hz) after 50 minutes from ingestion of the brew and increased slow- and fast-gamma power (30–50 and 50–100 Hz, respectively) between 75 and 125 minutes. Alpha power reductions were mostly located at left parieto-occipital cortex, slow-gamma power increase was observed at left centro-parieto-occipital, left fronto-temporal and right frontal cortices while fast-gamma increases were significant at left centro-parieto-occipital, left fronto-temporal, right frontal and right parieto-occipital cortices. These effects were significantly associated with circulating levels of ayahuasca’s chemical compounds, mostly N,N-dimethyltryptamine (DMT), harmine, harmaline and tetrahydroharmine and some of their metabolites. An interpretation based on a cognitive and emotional framework relevant to the ritual use of ayahuasca, as well as it's potential therapeutic effects is offered.

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Unsubstantiated reports suggest that the availability and use of crack are increasing in São Paulo. To investigate this claim we used the databases from two outpatient clinics for drug users at a public hospital and examined the changes in the reported routes of administration of cocaine among 245 patients who had attended between 1990 and 1993. The proportion reporting crack use increased from 17% in 1990 to 64% in 1993 (p < .01). It does not seem that this increase was simply due to changes in demographic variables. Treatment policies need to be reviewed and HIV harm-reduction programs should focus more on the risks of sexual transmission.