*3.2.2 Gastrointestinal toxicities*

Gastrointestinal toxicities of nausea, vomiting, and diarrhea are frequently reported with PARPi as a class-wide adverse events.

Nausea and vomiting were reported in 53–77% and 22–40% of patients, respectively [21, 44, 47, 48, 51, 54, 55]. Nausea and vomiting were generally reported early, with the first onset within the first few months of PARPi treatment [48, 57]. Both nausea and vomiting were generally low grade (grade 1 or 2) and can be managed by dose interruption and/or dose reduction in majority of patients [21, 44, 47, 48, 51, 54, 55].

Olaparib, niraparib, and rucaparib are categorized as moderate to high emetic risks (≥30% frequency of emesis) per National Comprehensive Cancer Network® (NCCN) antiemesis guideline v2.022. While chemotherapy-induced nausea and vomiting (CINV) may seem transient, it can cause a negative impact on patient's quality of life [60]. HCPs should assess patients who are at increased risk for CINV and counsel patients proactively. Risk factors of CINV include younger age, female sex, previous history of CINV, little or no previous alcohol use, prone to motion sickness, history of morning sickness during pregnancy, and anxiety/high pretreatment expectation of nausea. The use of single-agent prophylaxis with 5-HT3 reception agonists; granisetron, ondansetron, or dolasetron is recommended for prevention of emesis. Lorazepam may be added with or without histamine-2 blocker or proton pump inhibitor [61]. Bedtime administration of PARPi may be a potential method for managing nausea [47].

Diarrhea frequently occurred in 18–37% of patients. Grade ≥ 3 was infrequent, observed in ≤3% of patients [21, 44, 47, 48, 51, 54, 55]. For patients with mild to moderate diarrhea (grade 1–2), symptoms can be managed by oral hydration, dietary modification to avoid all lactose-containing products, high-osmolar dietary supplements, and the use of loperamide [62].
