Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Marijuana Smoking”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1992

Middle cerebral artery velocity during upright posture after marijuana smoking.

Marijuana is known to cause symptoms suggestive of orthostatic hypotension such as dizziness and fainting during upright posture. We examined changes in cerebral blood velocity (CBV) and peripheral circulation during upright posture after smoking marijuana in 10 right-handed male subjects with a previous history of exposure to marijuana. The participants were physically and mentally healthy and drug-free for a minimum of 3 months before the experiment. Middle cerebral artery CBV, blood pressure and pulse rate were recorded during reclining position and standing, before and after smoking a high-potency marijuana cigarette or a placebo cigarette administered during 2 separate visits to the laboratory. The participants were questioned about dizziness during the upright position. Six of 10 subjects reported moderate to severe dizziness during standing after marijuana but not placebo. Subjects who experienced severe dizziness during standing showed marked decreases in blood pressure and CBV. Those who reported moderate dizziness showed reduction in CBV but not blood pressure. Subjects who reported mild dizziness after marijuana and after placebo smoking showed minimal changes in blood pressure and CBV. Cerebral ischemia during upright position after marijuana smoking may be caused by hypotension and impaired cerebral autoregulation.

Adult↗
PubMed1989

Breathhold duration and response to marijuana smoke.

Marijuana smokers are frequently observed to hold the smoke in their lungs for prolonged periods (10-15 sec) apparently in the belief that prolonged breathholding intensifies the effects of the drug. The actual influence of breathhold duration on response to marijuana smoke has not been studied. The present study examined the effects of systematic manipulation of breathhold duration on the physiological, cognitive and subjective response to marijuana smoke in a group of eight regular marijuana smokers. Subjects were exposed to each of three breathhold duration conditions (0, 10 and 20 sec) on three occasions, scheduled according to a randomized block design. A controlled smoking procedure was used in which the number of puffs, puff volume and postpuff inhalation volume were held constant. Expired air carbon monoxide levels were measured before and after smoking to monitor smoke intake. Typical marijuana effects (increased heart rate, increased ratings of "high" and impaired memory performance) were observed under each of the breathhold conditions, but there was little evidence that response to marijuana was a function of breathhold duration.

Adolescent↗
PubMed1996

Characteristics of Jamaicans who smoke marijuana before sex and their risk status for sexually transmitted diseases.

Because of the high prevalence of marijuana smoking in Jamaica, it is important to know if this practice is associated with increased risk for STD infections. A national sample of 2 580 randomly selected Jamaicans, aged 15 to 49 years were administered a questionnaire to measure a number of health and behavioural variables. The results indicated that more persons who smoked marijuana before sex had a history of STD infections than non-marijuana smokers, the difference was significant among men (46% vs 26%, p < 0.001) but not among women (19% vs 8%, p = 0.09). There was no difference in age, however, more of the smokers were unmarried, poorly educated and unemployed than persons who did not smoke marijuana before sex. They were also more likely to engage in high risk sex behaviours and other risk taking behaviors than non-smokers. The results of multiple logistic regression analyses indicated that marijuana smoking before sex was an independent risk factor for STDs among men (Odds Ratio = 2.0, p = 0.04). Although it was not possible to determine if the association was causal, the increased risk for STDs among men who smoke marijuana before sex should be incorporated into the Jamaican STD/AIDS control programme by making special efforts to encourage condom use among marijuana smokers.

Adolescent↗
PubMed1994

Short-term effects of smoking marijuana on balance in patients with multiple sclerosis and normal volunteers.

A double-blind randomized placebo-controlled study of inhaled marijuana smoke on postural responses was performed in 10 adult patients with spastic multiple sclerosis (MS) and 10 normal volunteers matched as closely as possible for age, sex, and weight. A computer-controlled dynamic posturographic platform with a video line scan camera measured shoulder displacement in response to pseudorandom platform movements. Premarijuana smoking patient tracking was inferior to that of the normal volunteers as indicated by the higher noise variance of the former. Smoking one marijuana cigarette containing 1.54% delta 9-tetrahydrocannabinol increased postural tracking error in both the patients and normal control subjects with both eyes open and closed; this untoward effect was greatest for the patients. The tracking error was also accompanied by a decrease in response speed for the patients with their eyes closed. Marijuana smoking further impairs posture and balance in patients with spastic MS.

Adult↗
PubMed1996

Successfully treated invasive pulmonary aspergillosis associated with smoking marijuana in a renal transplant recipient.

Invasive pulmonary aspergillosis (IPA) is often a lethal entity in transplant recipients (up to 90%). We report the successful treatment of a case of IPA in a renal transplant recipient whose only risk for exposure was habitual marijuana smoking. Although marijuana smoking has been linked to the development of IPA in patients immunosuppressed for a variety of reasons, this case is the first report involving a solid organ transplant recipient. The patient's clinical course and treatment are described and the literature is reviewed with respect to environmental and patient risk factors. In this case, IPA was associated with the patient's heavy usage of marijuana during the immediate posttransplant period. Treatment was successful and included the experimental amphotericin product amphotericin B colloidal dispersion. Contemporaneous exposure to a large amount of inocula of Aspergillus within 30 days of receiving high doses of steroids appeared to be the most important factor that predisposed this patient to IPA. Transplant recipients should be specifically proscribed from marijuana use during periods of high steroid administration.

Antifungal Agents↗
PubMed2001

Effects of acute smoked marijuana on complex cognitive performance.

Although the ability to perform complex cognitive operations is assumed to be impaired following acute marijuana smoking, complex cognitive performance after acute marijuana use has not been adequately assessed under experimental conditions. In the present study, we used a within-participant double-blind design to evaluate the effects acute marijuana smoking on complex cognitive performance in experienced marijuana smokers. Eighteen healthy research volunteers (8 females, 10 males), averaging 24 marijuana cigarettes per week, completed this three-session outpatient study; sessions were separated by at least 72-hrs. During sessions, participants completed baseline computerized cognitive tasks, smoked a single marijuana cigarette (0%, 1.8%, or 3.9% Delta(9)-THC w/w), and completed additional cognitive tasks. Blood pressure, heart rate, and subjective effects were also assessed throughout sessions. Marijuana cigarettes were administered in a double-blind fashion and the sequence of Delta(9)-THC concentration order was balanced across participants. Although marijuana significantly increased the number of premature responses and the time participants required to complete several tasks, it had no effect on accuracy on measures of cognitive flexibility, mental calculation, and reasoning. Additionally, heart rate and several subjective-effect ratings (e.g., "Good Drug Effect," "High," "Mellow") were significantly increased in a Delta(9)-THC concentration-dependent manner. These data demonstrate that acute marijuana smoking produced minimal effects on complex cognitive task performance in experienced marijuana users.

Adult↗
PubMed1992

Regional cerebral blood flow after marijuana smoking.

Regional CBF was measured with the 133Xe inhalation technique before and thrice after smoking marijuana of two strengths and placebo in 20 physically and mentally healthy male volunteers with a previous history of exposure to marijuana. They were drug-free at the time of the study. Blood pressure, pulse rate, end-tidal carbon dioxide, end-tidal carbon monoxide, and forehead skin perfusion were quantified during the CBF measurements. Blood samples were drawn for quantification of plasma levels of delta 9-tetrahydrocannabinol (THC) before and during the 2 h after smoking marijuana or placebo. Drug-induced intoxication and changes in mood were quantified with rating scales. Marijuana smoking was associated with bilateral CBF increase, which was maximal 30 min later. Greater CBF increases were seen in the frontal region and right hemisphere. No significant CBF changes were seen after placebo. Pulse rate and respiration increased significantly after marijuana but not placebo. Both marijuana and placebo smoking were associated with increased end-tidal carbon monoxide. CBF increase in both hemispheres correlated significantly with degree of intoxication, plasma levels of THC, and pulse rate.

Adult↗
PubMed1988

A cumulative dosing procedure for administering marijuana smoke to humans.

Subjective, behavioral and physiological effects of smoked marijuana were measured with a cumulative dosing procedure which allowed dose-related effects to be determined within a single experimental session. Five male and three female occasional marijuana smokers participated. Unit doses of marijuana smoke were administered in a standardized manner on four occasions during each session, each occasion spaced 20 minutes apart. This procedure resulted in a cumulative dose of active (1.4%-THC) marijuana of 0, 2, 4 and 8 puffs after the four successive smoking occasions, respectively. Dependent variables were measured after each smoking occasion. Smoke absorption was monitored by measuring expired air carbon monoxide levels. Subjects participated in three identical sessions spaced a week apart in order to assess the reliability of the procedure. During a fourth session, only placebo (0.0%-THC) marijuana was administered throughout the session as a control. Significant linear dose-effect functions were obtained on several measures, with good session-to-session replicability of most effects. The results demonstrate the feasibility of using a cumulative dosing procedure to evaluate dose-related effects of smoked marijuana in humans. The procedure would be especially useful for the assessment of shifts in dose-effect curves as a result of various experimental manipulations.

Adolescent↗
PubMed1984

Reinforcing properties of oral delta 9-tetrahydrocannabinol, smoked marijuana, and nabilone: influence of previous marijuana use.

The reinforcing properties of delta 9THC (17.5 mg), a 1 g marijuana cigarette containing 1.83% delta 9-THC, a synthetic cannabis compound (Nabilone 2 mg orally), and their respective placebos were assessed with self-report and operant work-contingent choice procedures. Three groups of eight subjects were selected on the basis of a history of regular, intermittent, or occasional marijuana-smoking behavior. All subjects served as their own controls for each drug condition and studies were carried out under double-blind and "double-dummy" conditions in a controlled, residential research ward. Placebo responding did not vary as a function of history of marijuana use, but the past history of drug use had a significant influence on the reinforcing properties of cannabis compounds as well as the behavioral and physiological effects of these drugs. Regular marijuana users reported a significant increase in elation following marijuana smoking, but this was not associated with a significant increment in pulse rate. Intermittent and occasional marijuana smokers had significant increases in pulse rate, but no significant marijuana-induced elation. Nabilone and delta 9-THC produced a significant increase in pulse rate for all subject groups, but there was no significant increase in elation following ingestion of these compounds. Given a choice between the three drugs and three placebos, 18 of 23 subjects worked to obtain a marijuana cigarette in an operant work choice paradigm. These data indicate that smoked marijuana was significantly more reinforcing than all other cannabis compounds studied, regardless of past drug-use history.

Adult↗
PubMed1997

Brodifacoum intoxication with marijuana smoking.

We report the case of a 17-year-old boy with a significant history of drug and alcohol abuse, which included smoking marijuana mixed with brodifacoum. As a consequence, the patient developed a prolonged coagulopathy that persisted for more than 1 year. To our knowledge, this is the first case reported in the literature in which super-warfarin intoxication has been associated with marijuana smoking. This report should increase the awareness of pathologists and clinicians when examining a patient with a history of drug abuse who exhibits persistent vitamin K1-dependent coagulopathy.

4-Hydroxycoumarins↗
PubMed2002

Effects of smoked marijuana in healthy and HIV + marijuana smokers.

This article presents data from two avenues of marijuana research. First, the author shows that daily marijuana smoking in healthy individuals produces dependence, as demonstrated by withdrawal symptoms such as increased irritability and depression and decreased food intake. In addition, two antidepressant medications were evaluated to assess their potential effectiveness in the treatment of marijuana withdrawal symptoms: (1) sustained-release bupropion (0, 300 mg/day) and (2) nefazodone (0, 450 mg/day). Research participants were regular marijuana smokers who lived in a residential laboratory in groups of two to four. While inpatients, participants smoked active marijuana (2.8%-3.1% THC) repeatedly for 4 days, followed by 8 to 12 days of placebo marijuana (0.0% THC). Results show that during marijuana abstinence, (1) bupropion increased ratings of irritability, depression, and stomach pain and decreased food intake and sleep quality compared to placebo maintenance, and (2) nefazodone decreased anxiety during marijuana withdrawal but did not alter ratings of irritability and misery. Thus, neither medication showed promise as potential treatments for symptoms of marijuana withdrawal. The second avenue of research focused on the effect of cannabinoids in individuals with muscle mass loss, an indicator of wasting in HIV illness. Given that there are little scientific data contributing to the debates concerning medical marijuana, this study directly compared the effects of oral delta9-THC (0, 10, 20, 30 mg PO) to smoked marijuana (0.0%, 1.8%, 2.8%, 3.9% THC) in HIV + marijuana smokers with muscle mass loss (< 90% body cell mass/height). Multiple dimensions of human behavior were measured, including food intake, mood, and cognitive performance. Drugs were administered using a within-subject, double-blind, staggered, double-dummy design. Participants were free to self-select from a variety of foods throughout most of the session. Preliminary data (n = 9) suggest that oral THC was more effective at increasing food intake, but the volunteers "liked" the effects of smoked marijuana more than the effects of oral THC.

Bupropion↗
PubMed1990

Smoked marijuana effects on tobacco cigarette smoking behavior.

The effects of marijuana smoke exposure on several measures of tobacco cigarette smoking behavior were examined. Eight healthy adult male volunteers, who smoked both tobacco and marijuana cigarettes, participated in residential studies, lasting 10 to 15 days, designed to measure the effects of marijuana smoke exposure on a range of behavioral variables. Tobacco cigarettes were available throughout the day (9:00 A.M. until midnight). Each day was divided into a private period (9:00 A.M. to 5:00 P.M.), during which subjects were socially isolated, and a social period (5:00 P.M. to midnight), during which subjects could interact. Under blind conditions, subjects smoked placebo and active marijuana cigarettes (0%, 1.3%, 2.3%, or 2.7% delta 9-tetrahydrocannabinol) four times daily (9:45 A.M., 1:30 P.M., 5:00 P.M. and 8:30 P.M.). Each subject was exposed to both placebo and one active dose over 2- to 5-consecutive-day intervals, and dose conditions (i.e., placebo or active) alternated throughout the study. Active marijuana smoking significantly decreased the number of daily tobacco smoking bouts, increased inter-bout intervals and decreased inter-puff intervals. Marijuana decreased the number of tobacco smoking bouts by delaying the initiation of tobacco cigarette smoking immediately after marijuana smoking, whereas decreases in inter-puff intervals were unrelated to the time of marijuana smoking. No consistent interactions between marijuana effects and social or private periods (i.e., time of day) were observed.

Adult↗
PubMed2001

The pharmacological activity of inhalation exposure to marijuana smoke in mice.

Although the majority of cannabinoid users smoke marijuana, the preponderance of laboratory animal research is based on administration of Delta9-tetrahydrocannabinol (Delta9-THC) or other cannabinoid agents via injection. The aim of the present study was to evaluate the impact of inhaling marijuana, or ethanol-extracted placebo smoke in the mouse model of cannabinoid activity by assessing inhibition of spontaneous activity, antinociception, catalepsy, and body temperature. In order to determine dosimetry, blood levels of Delta9-THC were obtained following either marijuana exposure or intravenous injection of Delta(9)-THC. Inhalation exposure to marijuana produced dose-related increases in antinociception and catalepsy, with estimated ED50 doses of Delta9-THC of 2.4 and 3.8 mg/kg, respectively. However, hypothermia and locomotor depression occurred in both the placebo- and marijuana-exposed mice. The CB1 receptor antagonist, SR 141716A antagonized the antinociceptive effects of marijuana (AD50 = 0.6 mg/kg), but only slightly decreased marijuana-induced catalepsy, and failed to alter either the hypothermic or locomotor depressive effects. In contrast, SR 141716A antagonized the antinociceptive, cataleptic, and hypothermic effects of intravenously administered Delta9-THC in mice that were exposed to air alone, though all subjects exhibited locomotor depression, possibly related to the restraint. In accordance with reports of others, these data suggest that exposure to smoke alone has pharmacological consequences. Our findings also indicate that marijuana-induced antinociception is mediated through a CB1-receptor mechanism of action and are consistent with the notion that Delta9-THC is mainly responsible for this effect.

Administration, Inhalation↗
PubMed1989

The regularity of smoked marijuana self-administration.

Three male research volunteers lived in a residential laboratory for 12 days in a study designed to investigate factors controlling patterns of marijuana smoking. All contact with the experimenters was through a networked computer system and subjects' behaviors were continuously recorded. During the first six hr of the day (0945-1545), subjects remained in their private rooms engaging in planned work activities, and during the remainder of the day (7 3/4 hr) they were allowed to socialize (1600-2345). Subjects were instructed that up to five active marijuana cigarettes (1.84% delta 9 w/w THC) could be smoked on designated days between 0945 and 2200. Cigarettes were available on request. Subjects requested all five cigarettes on 15 of 18 possible occasions (three subjects x six days of availability) with a mean latency to the first cigarette of 22 min. The pattern of self-administration was remarkably similar among subjects with all subjects smoking two cigarettes during the private work period and three cigarettes during the social access period. Subjects 1 and 2 smoked 90% of their social period cigarettes together in the social area, while Subject 3 smoked all of his cigarettes alone in his private room.

Adult↗
PubMed1995

Effects of smoking marijuana, tobacco or cocaine alone or in combination on DNA damage in human alveolar macrophages.

This study examined the role of marijuana smoking in the pathogenesis of human lung cancer by measuring DNA damage in alveolar macrophages (AM). The alkaline unwinding method was used to determine DNA single-strand breaks in AM lavaged from non-smokers [NS] and smokers of marijuana [MS], tobacco [TS] or cocaine [CS], either alone or in combination. DNA damage was related to superoxide anion (O2-) production by AM stimulated with phorbol myristate acetate (PMA) and to nitric oxide content of smoke using cellular nitrite (NO2-) concentrations. The percentage of double-stranded DNA present after alkaline unwinding was higher in AM of NS (41 +/- 5% [11]) and CS (41 +/- 4% [9]) versus that of MS (31 +/- 4% [8]), TS (35 +/- 3% [11]), MTS (26 +/- 4% [3]), and CTS (27 +/- 5%* [10]), mean +/- SEM [n], * = p < 0.1 vs. NS). PMA stimulated O2- production by AM from NS and CS was lower than that of other smokers, but the differences were not significant. O2- release, however, had an inverse correlation with DNA single-strand breaks (r = -0.38, p = 0.009). Nitrite content of AM from NS and CS was less than that of other smokers' cells (p < 0.1 for TS & CTS vs. NS), but DNA damage had no relationship to NO2- concentration. We conclude that AM recovered from MS, either alone or in combination with tobacco smoking, show a trend towards DNA damage. Studies utilizing a larger population should verify our findings and further define its relationship to enhanced oxidant production by macrophages.

Cocaine↗
PubMed1993

Acute changes in cerebral blood flow after smoking marijuana.

In experienced marijuana smokers, marijuana smoking was accompanied by a significant bilateral increase in cerebral blood flow (CBF) especially in the frontal regions and cerebral blood velocity. The post-marijuana CBF increase could not be explained on the basis on changes in general circulation or respiration. Similarly, the CBF increase was unrelated to plasma levels of tetrahydrocannabinol and extracranial circulation. Behavioral changes showed significant correlations with CBF. CBF and brain function are closely coupled and therefore it seemed highly likely that CBF changes after marijuana were closely related to its effect on mood and behavior.

Adult↗
PubMed1977

Effect of marijuana and placebo-marijuana smoking on psychological state and on psychophysiological cardiovascular functioning in anginal patients.

Ten male anginal patients with angiographically documented coronary artery disease, in a randomized double-blind crossover study, smoked one marijuana cigarette (containing 18 mg of delta-9-THC) on one morning and one placebo marijuana cigarette (containing 0.05 mg of delta-9-THC) on a successive morning. Significant increases occurred in average cognitive and intellectual impairment scores, derived from the objective content analysis of 5 min of speech, 30 mins after smoking the marijuana cigarette as compared to the placebo marijuana cigarette, and these scores decreased to near presmoking levels 60 min after smoking. No significant average changes occurred in anxiety or three hostility scale scores following smoking marijuana. Sizable individual differences were noted in the psychological responses to marijuana smoking due, presumably, to personality differences and/or differences in THC pharmacokinetics. Significant psychocardiovascular hemodynamic correlations, as measured by echocardiography, were observed during placebo-marijuana smoking between hostility inward scores and systolic blood pressure and ejection fraction, overt hostility outward scores and diastolic blood pressure, as well as between anxiety scores and stroke volume and left ventricular end-diastolic dimension and left ventricular diastolic volume. These significant psychophysiologic correlations were all eliminated during marijuana smoking. In view of associated findings that marijuana smoking decreased myocardial oxygen delivery, decreased exercise time until the onset of anginal pain, and increased myocardial oxygen demand in anginal patients, the use of marijuana by such patients is clearly inadvisable.

Adult↗
PubMed2002

Respiratory and immunologic consequences of marijuana smoking.

Habitual smoking of marijuana has a number of effects on the respiratory and immune systems that may be clinically relevant. These include alterations in lung function ranging from no to mild airflow obstruction without evidence of diffusion impairment, an increased prevalence of acute and chronic bronchitis, striking endoscopic findings of airway injury (erythema, edema, and increased secretions) that correlate with histopathological alterations in bronchial biopsies, and dysregulated growth of the bronchial epithelium associated with altered expression of nuclear and cytoplasmic proteins involved in the pathogenesis of bronchogenic carcinoma. Other consequences of regular marijuana use include ultrastructual abnormalities in human alveolar macrophages along with impairment of their cytokine production, antimicrobial activity, and tumoricidal function. Cannabinoid receptor expression is altered in leukocytes collected from the blood of chronic smokers, and experimental models support a role for delta9-tetrahydrocannabinol in suppressing T cell function and cell-mediated immunity. The potential for marijuana smoking to predispose to the development of respiratory malignancy is suggested by several lines of evidence, including the presence of potent carcinogens in marijuana smoke and their resulting deposition in the lung, the occurrence of premalignant changes in bronchial biopsies obtained from smokers of marijuana in the absence of tobacco, impairment of antitumor immune defenses by delta9-tetrahydrocannabinol, and several clinical case series in which marijuana smokers were disproportionately over represented among young individuals who developed upper or lower respiratory tract cancer. Additional well designed epidemiological and immune monitoring studies are required to determine the potential causal relationship between marijuana use and the development of respiratory infection and/or cancer.

Bronchi↗