The main cause of nausea and vomiting in cancer patients is the emetogenic effect of chemotherapeutic agents on the gastrointestinal tract, liver and brain.
In addition to a marked decrease in the quality of life of patients receiving chemotherapy, nausea and vomiting can be the cause:
- development of electrolyte disorders, dehydration, aspiration pneumonia, anorexia; loss of body weight;
- increasing the intervals between cycles of chemotherapy, lowering the doses of drugs, abandoning the planned treatment, which can be the reason for the deterioration of the results of therapy and, in the case of a highly sensitive tumour, it does not allow to achieve a cure.
There are two most likely mechanisms for the development of acute nausea and vomiting during chemotherapy:
- peripheral mechanism: the metabolites of antitumor drugs when ingested into the gastrointestinal tract with bile irritates the enterochromaffin cells of the intestinal mucosa, this leads to the release of serotonin and the excitation of the serotonin (5HT3 receptor) receptors of the n termini. vagus; excitation through n. vagus is transmitted to the trigger zone of the medulla oblongata, and from there to the vomiting centre;
- central mechanism: it was found that 5HT3 receptors are contained directly in the trigger zone of the medulla oblongata and can be directly activated by serotonin isolated by enterochromaffin cells.
For the treatment of nausea and vomiting in cancer patients, the following groups of drugs are used:
- antagonists of the serotonin receptors – ondansetron (zofran, latran), troposetron (Navoban), granisetron (kitril), dolasetron (anzemet);
- dopamine antagonists – metoclopramide;
- corticosteroids – dexamethasone;
- benzodiazepines – lorazepam (ativan, loram, merlit), diazepam (valium, seduxen); neuroleptics – prochlorperazine, haloperidol.
The treatment of nausea and vomiting in cancer patients (due to chemotherapy) depends on their type, namely they refer to “premature”, “acute” or “delayed”.
Premature nausea and vomiting
Nausea (and vomiting) is “premature” if its occurrence precedes the introduction of chemotherapy drugs; this kind of nausea (and vomiting) can develop in patients who have previously received chemotherapeutic treatment, accompanied by severe nausea and vomiting. Nausea and vomiting occur when the patient is preparing for the introduction of cytostatics (a type of medical personnel, syringes and droppers with diluted drugs, etc.), and sometimes only from one thought about the impending treatment.
The most effective method of combating premature nausea and vomiting is the prevention of acute nausea and vomiting in previous courses of treatment. Given the psychogenic nature of this complication, it is advisable to use sedatives: diazepam 5 mg or lorazepam 1-2 mg every 6-12 hours.
Acute nausea and vomiting
Nausea (and vomiting) is “acute” if it develops within the first 24 hours after the administration of chemotherapy drugs. Her treatment depends on the level of emetogenicity of the drug (which is already pre-calculated for each drug and is a reference indicator). This indicator, in the case of using a combination of chemotherapy drugs, is calculated by the attending physician (oncologist) before starting the chemotherapy and, accordingly, the received indicator (mild, moderate, highly emetic) appoints the corresponding (antiemetic) therapy.
The most painful symptoms develop with the appointment of cisplatin, dacarbazine, nitrosourea, as well as combined chemotherapy.
Kupirovanie acute nausea and vomiting in the appointment of highly or moderately emetogenic drugs. Oral administration 30 minutes prior to chemotherapy: granisetron 2 mg or dolasetron 100 mg, or tropisetron 5 mg, or ondansetron 12-24 mg + dexamethasone 20 mg ± lorazepam 1-2 mg. If oral administration is not possible, granisetron 1 mg or dolasetron 100 mg or tropisetron 5 mg or ondansetron 16-24 mg + dexamethasone 20 mg ± lorazepam 1-2 mg is administered before the start of chemotherapy. If you need daily administration of emetogenic cytotoxic agents, this scheme is used daily.
Coping with acute nausea and vomiting in the appointment of weakly emetic agents. Oral reception 30 min before the start of chemotherapy: dexamethasone 20 mg ± lorazepam 1-2 mg. If oral administration is not possible before the start of chemotherapy: dexamethasone 20 mg ± lorazepam 1-2 mg.