A pill may work as well as a puff when it comes to using marijuana to treat pain according to a small but carefully controlled new
study. Pain relief from pills may last longer, however, and may not leave
people feeling as high as they do after they smoke the drug.
Medical marijuana is now legal in 18 states and the District
of Columbia, according to the nonprofit group ProCon.org. Surveys show pain is
one of the main reasons doctors prescribe it. But studies testing marijuana as
a pain reliever have had mixed results. Some have shown that it works as well
as mild opioid (narcotic) pain relievers like codeine, while others have
indicated that the drug might actually make pain worse.
To learn more, researchers at the Substance Use Research
Center of the New York State Psychiatric Institute pitted two strengths of
smoked marijuana against two strengths of the drug dronabinol, which contains
tetrahydrocannabinol, or THC, the same active ingredient as in marijuana
Dronabinol has been FDA-approved since 1985 to treat the
nausea and loss of appetite that commonly afflict patients with cancer and Aids.
Less is known about its effects on pain.
For the government-sponsored study, researchers recruited 30
healthy, pain-free men and women who were already regular marijuana smokers.
During five experimental sessions, participants took a
capsule and then 45 minutes later smoked a marijuana cigarette. The capsules
contained either an inactive placebo, or 10 milligrams or 20 milligrams of
dronabinol. The cigarettes were specially made by the US National Institute on
Drug Abuse, which funded the study. Cigarettes were standardised to contain
marijuana with no THC, a low dose of the drug or a higher dose.
People in the study never knew whether they were smoking or
swallowing the drug or how strong the dose was. Researchers made sure they
never got a double hit of the drug during the same session.
The testing days were spaced at least two days apart, and
participants were asked to refrain from smoking the night before their lab
pain in study
Several times during the sessions, researchers had each
person place their hands in a water bath kept just above freezing temperatures.
They measured how long it took study participants to feel pain and then how
long they were able to tolerate the pain before they yanked their hand out of
the water. Participants also answered questions about how intensely they felt
the pain during the experiments and how high they felt.
When researchers tallied their data, they found that both
the smoked drug and the pill were about equally effective at controlling pain.
After smoking the strongest cigarettes or taking the highest
strength of the pill, it took people an average of about 12 to 13 seconds
longer to report feeling pain from the cold water compared to when they took
the placebos. Both forms of the drug also significantly increased pain
tolerance, the amount of time a person was able to stand the pain before they
pulled their hand out of the cold water.
Additionally, study participants reported that their pain
was decreased after they smoked either strength of marijuana cigarette and
after they took the highest strength of the dronabinol capsules.
The biggest differences between the puffs and the pills had
to do with how long it took the drug to work and how high people felt after
they used it.
Pain relieve peaked
15 minutes after smoking marijuana
Researchers found that pain relief peaked about 15 minutes
after people smoked the marijuana and wore off relatively quickly. The pills
took longer to work, but the pain relief lasted three to four hours.
Participants also reported feeling much higher after smoking
the drug compared to when they swallowed it. The feeling of being high usually
outlasted any pain relief.
"If you think about it, if you're someone who's dealing
with chronic pain, you're going to have to be smoking several times a day, and
for a lot of people that would not be feasible," said study author Ziva
Cooper, an assistant professor of clinical neurobiology at Columbia University,
in New York City.
Cooper also noted that swallowing a pill might be a safer
way to take the drug than smoking it. There's some concern, though scant
evidence, that smoking marijuana might increase the risk for lung cancer.
Dr Gary Reisfield, an assistant professor of addiction
medicine and chief of pain management services at the University of Florida
College of Medicine, in Gainesville, praised the study for being
"well-conceived and meticulously designed."
He said the research should help doctors and patients better
understand how to use the drug.
Management of chronic
"Smoked cannabis works faster, but oral THC works
longer. For the management of chronic pain and other symptoms, the duration of
action is often more important than the rapidity of onset. It is more
convenient, and often more desirable, to administer a medication two or three
times daily rather [than] every two or three hours," said Reisfield, who
was not involved in the research.
When it comes to price, it costs somewhat more to swallow
average doses of the drug than to smoke it, according to ProCon.org. At an
average dose of two joints a day, it costs about $514 a month to smoke
marijuana. The usual dose of dronabinol, which is the generic form of the drug
Marinol, costs about $678 a month.
But dronabinol is often covered by insurance, so an insured
patient would pay far less, between $15 and $30 each month for their
The study was published April 22 in the journal Neuropsychopharmacology.
For more on marijuana, visit the US National Institute on