Prochlorperazine for Breakthrough CINV

To provide preliminary prospective evidence of the efficacy of individual agents prescribed for the treatment of breakthrough chemotherapy-induced nausea and vomiting (CINV)

Patients receiving moderately or highly emetogenic chemotherapy received prophylactic antiemetic treatment based on guidelines. If patients experienced breakthrough CINV, their treating oncologist prescribed antiemetics with discretion and the patients were instructed to complete a questionnaire starting at the point in which they took the antiemetic (baseline) and then every 30 minutes for four hours.

• The sample consisted of 96 participants.
• Median age was 58 with a range of 30–86.
• The sample was 45% male and 55% female. Of the patients completing the questionnaire, 26% were male and 74% were female.
• Diagnoses were breast (7%), GI (26%), genitourinary (4%), skin (4%), lung (13%), gynecologic (23%), head and neck (4%), neuroendocrine (1%), sarcoma (3%), and hematologic (15%).
• Patients were receiving  moderately to highly emetogenic chemotherapy.

The study was conducted at a single site at the Mayo Clinic in Minnesota, United States.

All patients were in active treatment.

The study has applications for late effects and survivorship.

This was a prospective, exploratory observation study.

• Patients rated nausea on a scale of 0–10.
• Patients recorded the number of episodes of vomiting and side effects (e.g., agitation, drowsiness [on a scale of 0–10], headache).
• Patients completed nausea and vomiting questionnaires.

Of the total patients enrolled, 28% experienced breakthrough CINV and completed the questionnaire.

The breakthrough medications given were 10-mg oral prochlorperazine (88%) or a 5-HT₃ receptor antagonist (RA) (12%) (specifically, 1 mg granisetron, 8-mg IV ondansetron, 8-mg sublingual ondansetron).

Patients receiving the prochlorperazine experienced a 75% median reduction in nausea after four hours, and vomiting was reduced from 21% to 4%. Of these, 96% reported they would recommend prochlorperazine to other patients (median satisfaction as 8 out of 10).

Patients who received the 5-HT₃ receptor antagonists experienced a 75% median reduction in nausea over the four-hour study period. No vomiting from baseline was reported (satisfaction as 0, 4, and 8 out of 10). The patient who rated satisfaction at 0 recorded complete resolution of nausea by 30 minutes and said would recommend the medication to others, so investigators posited that this patient may have misunderstood the high satisfaction score of 0 rather than 10.

In the patients treated with prochlorperazine, the median drowsiness of 3 at baseline decreased to 2 after four hours. Headache was reported in 20% of patients and decreased to 0% after four hours. Agitation was reported in 20% of patients and decreased to 4% after four hours. Abdominal cramping, dry mouth, tachycardia, blurry vision were also recorded.

In the patients treated with 5-HT₃ RAs, baseline drowsiness of 5 remained unchanged after four hours. One patient did not have drowsiness at baseline but reported drowsiness of 1 after taking the medication. No patients reported headache, agitation, or other toxicities.

Prochlorperazine and 5-HT₃ RAs appeared to be effective breakthrough antiemetic therapies with favorable outcomes. Prochlorperazine is a good choice base on this study as it acts on a different pathway than prophylactic antiemetics. Further randomized, controlled trials would elucidate more effective antiemetic approaches for treating nausea.

• No appropriate control group was included.
• The analyzable sample size was small.
• The study did not provide a clear control for prophylactic antiemetic regimens.

Prochlorperazine has been used for a long time as a rescue medication. This study supports the choice of antiemetic for breakthrough CINV with minimal side effects. Further randomized controlled trials comparing different side effects are clearly recommended.