Throughout this document ‘chemotherapy’ is used as an umbrella term and includes: antineoplastic drugs, hormonal agents, immune-system-modifying (immunomodifiers), biological and molecular targeted therapies.
Within the treatment protocols eviQ must include default antiemetics. The antiemetics chosen are based upon available evidence and clinical practice (which takes into consideration the efficacy, patient preference and availability on the PBS). These are only a default and may vary between institutions and can be substituted to reflect individual institutional policy.
Nausea and vomiting is one of the most frequently experienced side effects encountered by patients undergoing treatment with chemotherapy. Patients will often find the symptoms distressing and develop anxiety about the potential for such symptoms to recur with future cycles of chemotherapy.
Chemotherapy drugs vary in their ability to induce vomiting, and understanding the emetogenic potential of each chemotherapy drug and the overall treatment protocol is important in prescribing the appropriate prophylactic regimen.
Chemotherapy induced nausea and vomiting (CINV) is generally classified into three phases: acute, delayed and anticipatory.
- Acute emesis: occurring within the first 24 hours following administration of chemotherapy, and generally peaking in the first 5-6 hours.
- Delayed (or late) emesis: occurring more than 24 hours following administration of chemotherapy, and may last up to 6 to 7 days.
- Anticipatory emesis: occurring prior to treatment as a conditioned response in patients who have developed significant nausea and vomiting during previous cycles of chemotherapy. This may be triggered by various stimuli (e.g. smell and sight of treatment room). The incidence of anticipatory nausea and/or vomiting ranges from 18 to 57%, and nausea is more common than vomiting.r
Other categories include:
- Breakthrough emesis: development of nausea or vomiting, despite standard anti-emetic therapy; requires "rescue" with an additional agent.
- Refractory emesis: development of nausea or vomiting during subsequent treatment cycles when antiemetic prophylaxis and/or rescue have failed in earlier cycles.
It may be difficult to distinguish between acute and delayed phases when chemotherapy is given over a number of days or weeks. Optimal emetic control in the acute phase is essential to prevent nausea and vomiting in the delayed phase.
Radiation induced nausea and vomiting (RINV) is a common side effect of patients undergoing radiotherapy; it is related to radiation site, dose, volume irradiated and radiotherapy technique, and is generally milder than CINV. Read more about the management of radiation induced nausea and vomiting.
Consideration should also be given to patient-related factors which may increase the risk of CINV, including:
- female sex,
- prior chemotherapy,
- younger age (<50 years),
- history of motion sickness, and/or nausea in pregnancy,
- poor performance status,
- previous episodes of chemotherapy-associated emesis, and
- no alcohol consumption.
A chronic high consumption of alcohol, substance misuse or smoking appears to protect against CINV.