Orthostatic hypotension cannabis

Although they are generally more potent, the DMHP derivatives had effects In the normal volunteers at Edgewood that were very similar to those later described over the last 15 yr by many research laboratories working with cannabis and THC. After administration of DMHP, there was more orthostatic hypotension than with THC or cannabis and possibly fewer subjective and mood effects. The time course appeared more variable, and DMHP s effects were often slower or more erratic In onset, particularly when It was given orally, than were those of THC. DMHP s effects also persisted longer. 

Psychomotor Impairments were measured by such test batteries as the numerical facility, speed of closure, Purdue pegboard, and Strom-berg manual dexterity tests. Anecdotal reports, both by subjects and by staff, of changes In behavior and mood generally paralleled the other symptoms. The spectrum of the effects and their Intensity is similar to that commonly reported in the recent literature on cannabis studies in other volunteer populations. However, DMHP acetate seemed to elicit more orthostatic hypotension, and cannabis, a greater degree of mental effects. 

In summary, DMHP and some of its acetate Isomers produced various degrees of physical incapacitation due largely to the moderate to marked and prolonged orthostatic hypotension. Blood pressure was normal In the supine position. Mental effects of DMHP were much less severe than those of THC or cannabis at doses that produced similar degrees of orthostatic hypotension. Individual differences in intensity of response were considerable some subjects showed little or no response at doses that produced Intense symptoms in other subjects. 

Marijuana has several effects on the cardiovascular system, and can increase resting heart rate and supine blood pressure and cause postural hypotension. It is associated with an increase in myocardial oxygen demand and a decrease in oxygen supply. Peripheral vasodilatation, with increased blood flow, orthostatic hypotension, and tachycardia, can occur with normal recreational doses of cannabis. High doses of THC taken intravenously have often been associated with ventricular extra beats, a shortened PR interval, and reduced T wave amplitude, to which tolerance readily develops and which are reversible on withdrawal. While the other cardiovascular effects tend to decrease in chronic smokers, the degree of tachycardia continues to be exaggerated with exercise, as shown by bicycle ergometry. 

Cannabis and THC are known to increase heart rate, cardiac output and supine blood pressure, and can cause orthostatic hypotension (Jones 2002). Because of the resulting increase in cardiac work, cannabis and THC are probably best avoided by patients with clinically significant cardiovascular disorders. Cardiovascular effects tend to tolerate out over chronic dosing (Benowitz and Jones 1981). A survey of myocardial infarction survivors set out to investigate whether smoking marijuana... 

The major adverse medical effects of cannabis include increased heart rate, orthostatic hypotension, and respiratory irritation (from smoked caimabis). Thus, medical screening should include evaluation of the cardiovascular and respiratory systems. Individuals with a past or current condition that makes them less tolerant of increased heart rate (e.g., a cardiac arrhythmia, coronary artery disease), decreased Wood pressure (e.g., history of syncope), or respiratory irritation (e.g., asthma, hronchitis) should be excluded. 

Subjects should not be discharged from a cannabis-administration research study until they have been evaluated for any unresolved or residual adverse effects from study participation. Adverse physical and psychological effects from acute cannabis administration, such as tachycardia, orthostatic hypotension, impaired motor coordination, and drowsiness, usually resolve completely within hours. Thus, subjects can usually be safely discharged a few hours to a... 

Acute cardiovascular effects of cannabis administration include tachycardia, slightly increased blood pressure when supine, orthostatic hypotension, increased cardiac output, and decreased left ventricular ejection fraction (32,33). These effects increase myocardial oxygen demand at the same time... 

In view of the cardiovascular effects of marijuana, including tachycardia and a tendency to orthostatic hypotension, the use of cannabis by patients with cardiovascular disease is most certainly inadvisable. The older the individual, the greater the risk of unpleasant effects, including toxic psychoses. It would also seem better to avoid the use of marijuana in respiratory disease, in which it is likely to have some of the deleterious effects of tobacco smoking (SED VIII, p. 53). Finally, since cannabis passes the placental barrier, and in view of the many unanswered questions as to its basic effects, it would seem very unwise to take the material during pregnancy. The separate data on this topic have been reviewed very recently by Nis-himura and Tanimura (21 ). 

The effects of cannabis on the cardiovascular system would suggest the need for caution in the use of antihypertensive drugs, especially those tending to cause orthostatic hypotension, and in the use of agents themselves prone to induce tachycardia. 

---