Efficacy and tolerability of oral ondansetron versus prochlorperazine in the prevention of emesis associated with cyclophosphamide-based chemotherapy and maintenance of health-related quality of life

Cyclophosphamide causes activation of protein kinase A (PKA) in the brainstem of vomiting least shrews (Cryptotis parva)

Complete control of emesis caused by cyclophosphamide (CPA) is of immense interest to both patients and physicians. Serotonin 5-HT3- and tachykinin NK1-receptor antagonists are widely used antiemetics in clinic, but they fail to completely control CPA-induced emesis. New antiemetic targets for the full control of CPA-induced vomiting are lacking. We therefore examined the effects of CPA on emetic targets downstream of 5-HT3- and NK1- receptors in an attempt to better understand the molecular bases of CPA-induced emesis. Acute CPA (200 mg/kg, i.p.) administration in the least shrew caused a biphasic pattern of emesis over a 40 h observation period, with maximal peak vomit frequency during the 1st hour of treatment (acute phase), followed by a delayed-phase which peaks at 27th hour. The NK1 receptor mRNA levels increased significantly at 8 h post-CPA treatment in the brainstem, and at 28 h in the whole intestine. Substance P mRNA levels tended to increase both in the brainstem and intestine at most time-points post-CPA injection, however due to large variability, they failed to attain significance. Likewise, protein expression profiles of both NK1- and 5-HT3 -receptors in the brainstem were unchanged at any time-point. However, phosphorylation levels of protein kinase A (PKA), but not of extracellular signal-regulated protein kinase 1/2 (ERK1/2), were increased at 2, 8, 22, 28, and 33 h time-points after the treatment with CPA. Moreover, brainstem but not frontal cortex cAMP tissue levels tended to be elevated at most time-points, but significant increases occurred only at 1 and 2 h post-CPA treatment. The phosphodiesterase inhibitor, rolipram, caused significant increases in shrew brainstem cAMP levels which were associated with its capacity to produce vomiting, while pretreatment with SQ22536, an inhibitor of adenylyl cyclase, prevented rolipram-induced emesis. The results demonstrate that accumulation of cAMP and subsequent activation of PKA in the brainstem may help to initiate and sustain emesis induced by CPA in the least shrew. Our findings suggest that suppression of the cAMP/PKA cascade may have antiemetic potential in the management of CPA-induced emesis.

[Management of chemotherapy-induced emesis: what is the standard after 20 years of clinical research]

BACKGROUND

The knowledge of the importance, the physiopathological mechanisms, and the management of the chemotherapy-induced emesis has increased exponentially during the last 20 years. High-dosage metoclopramide (MCP) therapy has been introduced in the eighties and serotonine type-3 receptor antagonists (5-HT(3) antagonists) have been used since the late eighties and early nineties. Due to both classes of substances the results of the antiemetic therapies have improved drastically. After 20 years of intensive clinical research it seems to be appropriate to come to an intermediate conclusion.

METHOD

With the aid of an overview and a new analysis of the literature published on this topic so far, the current state of research is shown (including the fields in which further improvement will be necessary), and suggestions are made, wherever it seemed possible, to attain the "gold standard" in antiemetic therapy.

RESULTS AND CONCLUSIONS

In connection with all highly or very highly emetogenic chemotherapies, an antiemetic prophylaxis should be initiated on the day of therapy, especially when using platinum or most of the cyclophosphamide-based regimes for cancer treatment. The recommended prophylaxis consists of a combination of 5-HT(3) antagonists with a corticosteroid. To combat the so-called delayed emesis on the days following therapy, all patients should undergo an oral corticoid therapy, possibly in combination with MCP (especially platinum-therapy patients), less frequently with 5-HT(3) antagonists. With these means of prophylaxis emesis can be prevented/avoided completely in most patients, and nausea can at least be reduced. It is sufficient to administer a single dose of 5-HT(3) antagonists prior to chemotherapy. For ondansetron and granisetron, the best documented substances within this class of drugs, 8 mg (ondansteron) and 3 mg (granisetron) are considered standard dosages. Among the corticoids, most data have been accumulated for dexamethasone. A standard dose of 10 to 20 mg can be administered prior to chemotherapy. Right after and especially on the days following chemotherapy higher dosages seem to be indicated.

PROSPECT

Further therapy improvements, especially concerning emesis and nausea on the days following chemotherapy, are necessary and are currently object of clinical research.

Therapeutic use of cannabis: clarifying the debate

The debate regarding therapeutic use of cannabis is being confused by a lack of distinction between therapeutic and social use of cannabis. Separate consideration of therapeutic and social use would enable strategies to minimise any negative social impact of therapeutic use. For therapeutic use of cannabis to be considered on its own merits, greater emphasis needs to be placed on scientific evidence of therapeutic efficacy. At present the evidence is limited, it mostly relates to the use of synthetic cannabinoids, and much of it fails to compare cannabis with the best therapies available for the conditions of interest. Claims of therapeutic efficacy tend to be based on opinion and anecdote rather than the results of controlled studies. Further research is needed to clarify the potential therapeutic benefits, to enable claims of therapeutic use to be objectively assessed and to enable informed decisions to be made about the relative risks and benefits for any individual using cannabis for therapeutic purposes. Further research is required to clarify the efficacy of pure, synthetic cannabinoids compared to cannabis, the most effective route of administration, and the importance of delivering a known dose. The most likely value of cannabis is as an adjunct, rather than a replacement for, current medical approaches. The potential therapeutic benefits of cannabis will be greatest for those conditions where long-term cannabis use, with its attendant health risks, is not an issue and where the patient has the capacity to titrate dose against symptoms. There is sufficient evidence of potential therapeutic benefit to justify the facilitation of further research.

Functional relevance of antiemetic control. Experience using the FLIE questionnaire in a randomised study of the NK-1 antagonist aprepitant

Little information exists on the functional impact of effective antiemetic protection. In the present study, the Functional Living Index-Emesis (FLIE), was used to assess patient-reported impact of chemotherapy-induced nausea and vomiting (CINV) after administration of a new NK-1 receptor antagonist (aprepitant). Cisplatin-treated patients in a double-blind randomised trial received either aprepitant+dexamethasone+ondansetron on day 1 and aprepitant+dexamethasone on days 2-5 or standard antiemetic therapy (dexamethasone and ondansetron on day 1 and dexamethasone on days 2-5). Emetic events, nausea ratings and rescue medications were recorded in a 5-day diary and the FLIE was completed on day 6. Compared with standard therapy, significantly more patients treated with the high dose aprepitant regimen achieved a Complete Response (71 vs 44%, P<0.001) and also reported no impact on daily life as indicated by the FLIE total score (84 vs 66%, P<0.01). Use of the FLIE demonstrated that improved control of emesis was highly effective in reducing the impact of CINV on patients' daily lives.