Chemotherapy-Induced Nausea and Vomiting (CINV)
An estimated 80% of patients with cancer will experience chemotherapy-induced nausea and vomiting (CINV). The term CINV includes emesis and nausea, which can involve a loss of appetite and result in decreased oral intake of fluids and calories. Prevention is the primary goal in the management of CINV. Nausea and vomiting that are not controlled can cause the following:
- Chemical changes in the body.
- Mental changes.
- Loss of appetite.
- A torn esophagus.
- Broken bones.
- Reopening of surgical wounds.
Nausea and vomiting can occur before, during, or after treatment.
The types of nausea and vomiting include:
- Acute: Nausea and vomiting that happen within 24 hours after treatment starts.
- Delayed: Nausea and vomiting that happen more than 24 hours after chemotherapy. This is also called late nausea and vomiting.
- Anticipatory: Nausea and vomiting that happen before a chemotherapy treatment begins. If a patient has had nausea and vomiting after an earlier chemotherapy session, he or she may have anticipatory nausea and vomiting before the next treatment. This usually begins after the third or fourth treatment. The smells, sights, and sounds of the treatment room may remind the patient of previous times and may trigger nausea and vomiting before the chemotherapy session has even begun.
- Breakthrough: Nausea and vomiting that happen within 5 days after getting antinausea treatment. Different drugs or doses are needed to prevent more nausea and vomiting.
- Refractory: Nausea and vomiting that does not respond to drugs.
- Chronic: Nausea and vomiting that lasts for a period of time after treatment ends.
Cannabis can have strong effects on nausea and vomiting resulting from cancer chemotherapy or radiotherapy treatment. Supporting studies suggest that the addition of THC directly before and after chemotherapy offer more benefit than conventional antiemetic medications alone. Cannabis has been shown to stimulate appetite, a high caloric intake may contribute to weight gain and to the absorption of nutrients, often crucial in combating medical conditions.
Researchers from the University of Sydney, Chris O’Brien Lifehouse and the NHMRC Clinical Trials Centre have published preliminary results from a ground-breaking clinical trial of medicinal cannabis for cancer patients that found it could help reduce nausea and vomiting, two common and debilitating side effects of chemotherapy.
The pilot phase of the study ran for two-and-a-half years with 81 participants enrolled. To be included in the study, patients had to have already experienced nausea and vomiting during chemotherapy despite having taken nausea prevention medication.
In another study 15 participants receiving treatment with high-dose immunosuppressant were given both oral THC and smoked cannabis. Both oral THC and smoked cannabis were effective in reducing nausea and vomiting in 14 of 15 participants compared to placebo. Higher plasma levels of cannabis were associated with greater antiemetic effect.
In yet another study, fifty-five patients harbouring a variety of neoplasms and previously found to have severe nausea or emesis from antitumor drugs were given antiemetic prophylaxis in a double-blind, randomized crossover fashion. delta 9-Tetrahydrocannabinol (THC), a standard anti-sickness medicine, and placebo were compared. Nausea was absent in 40 of 55 patients receiving THC, in 8 of 55 patients receiving the anti-sickness medicine, and in 5 of 55 in the placebo group.
In a 2013 phase II crossover trial, thirty-one percent experienced moderate or severe cannabinoid-related adverse events such as sedation, dizziness, or disorientation, but 83% of participants preferred cannabis to placebo. No serious adverse events were attributed to THC:CBD.