Establishing the right dose of medical cannabis can be challenging since absorption and availability of cannabis’ active ingredients depends on whether the medical cannabis is being smoked, vaporized, eaten, or taken sublingually.
Calculating the proper dose of cannabis begins with speaking with your physician. Your doctor can suggest the amount of cannabis’ active ingredients that are recommended per dose for your medical condition. It’s unlikely that your physician will be familiar with how to dose herbal cannabis, so ask your doctor what dosage of THC, the primary active ingredient in most cannabis they would recommend if they were writing you a prescription for Marinol, the capsule form of THC dispensed by pharmacies. Marinol capsules are available in 2.5, 5 and 10 milligram doses of THC. From this dosage recommendation of Marinol, it is possible to estimate a dose of herbal cannabis, based on CBCB’s lab testing results.
At CBCB, the general rule of thumb for cannabis dosage is always: “Take the smallest amount of cannabis required to produce the intended medicinal effect.” Because of its low toxicity, doses of cannabis are often higher than actually needed, since a mild overdose of cannabis doesn’t produce the uncomfortable side effects associated with overdoses of more toxic medicines.
Portrayals of cannabis use on film and television often depict cannabis over-dosage. From Cheech and Chong movies of the 1970’s to the recent film, “Pineapple Express”, media depictions of cannabis emphasize the character’s ability to withstand enormous doses of cannabis. Most medical cannabis patients are influenced by these media depictions and tend to over-medicate.
For example, if a particular Phytologie cannabis strain contains 15% THC, then one gram of that cannabis would contain approximately 150 milligrams of THC. When smoked in a cannabis cigarette, much of this THC will be destroyed by combustion or lost in side-stream smoke. One study indicated that almost 75% of the available THC was lost when smoked in a cannabis cigarette.
If your physician recommends 5 milligrams of THC to reduce nausea before chemotherapy, then to smoke the medicine, divide a gram of 15% THC cannabis into eight equal portions and use one. If you were planning on using a vaporizer, you could divide that single portion in half, since vaporizers are more efficient in delivering THC than smoking. However, if you were going to ingest the dose by eating an edible, your body would absorb more of the THC, therefore you would only eat a quarter of that single portion. One rule of thumb is that eating properly cooked cannabis is twice as efficient as vaporizing and vaporizing is twice as efficient as smoking in delivering THC.