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The existence of a threshold serum metoclopramide level above which total protection from cisplatin-induced vomiting is more likely to occur has been proposed. We monitored serum metoclopramide levels prior to the third metoclopramide dose in the first cisplatin treatment cycle in patients receiving metoclopramide 2 mg/kg x 4 as part of a randomized double-blind cross-over study comparing single-agent metoclopramide with combination metoclopramide and dexamethasone. Serum samples from 35 patients (17 receiving single-agent metoclopramide and 18 receiving the combination) were analyzed using reverse-phase high-pressure liquid chromatography (HPLC). A wide variation in metoclopramide levels was observed (range 273-3380 ng/ml). Serum levels obtained from the same patient on multiple treatment cycles were well correlated, and the addition of dexamethasone did not alter serum metoclopramide levels. No threshold level could be identified for the two groups (single-agent or combination antiemetic therapy) considered individually or considered together. However, significantly more vomiting episodes and a lower incidence of total protection were noted in patients with metoclopramide levels above 1469 ng/ml receiving metoclopramide alone. This effect was nullified in the combination antiemetic group. Our data do not support a directly proportional relationship between serum metoclopramide level and antiemetic protection. However, a non-linear relationship with a possible agonist/antagonist effect is suggested. [ABSTRACT FROM AUTHOR]

Objectives: We hypothesize that prostate cancer (PC) patients who achieve and maintain an undetectable prostate-specific antigen (UD-PSA) on androgen deprivation therapy (ADT) have a predominantly androgen-dependent cancer cell population sensitive to apoptosis that allows for a prolonged time off ADT. This study summarizes patient- and treatment-related factors associated with a prolonged time off ADT in patients electing intermittent androgen deprivation (IAD)., Methods: Hormone-naïve patients with PC were treated with ADT using an antiandrogen and a luteinizing-hormone-releasing hormone-agonist. Of 255 consecutive patients, 216 (85%) achieved a UD-PSA (< 0.05 ng/ml). Ninety-three (43%) of 216 elected to stop ADT after maintaining a UD-PSA for a median of one year. Patients were followed off therapy and advised to restart ADT if the PSA level reached > or = 5.0 ng/ml. Forty-one patients received finasteride as part of IAD induction and as maintenance off therapy; these patients are excluded from the current study and are the focus of another publication. The remaining 52 patients are assessable for response being either in the off-phase of IAD > or = 1 year or having restarted IAD., Results: In the first IAD cycle, the median duration of the on-phase of IAD was 16 months (mean 19.0 months, range 3.6-71 months), and the median off-phase duration was 15.5 months (mean 24.1 months, range 3.2-87+ months). In 28 patients who maintained a UD-PSA for > or = 1 year, their median off-phase duration was 29 months (mean 35.8 months, range 7.8-87+ months), with nine (32%) still off IAD after a median follow-up of 62 months. Significant (p < 0.05) independent factors associated with prolonged off-phase duration by multivariate analysis included UD-PSA on ADT > or = 1 year (p = 0.010), PSA-only recurrence after local therapy (p = 0.039), and reaching a testosterone level > or = 150 ng/dl in > or = 4 months off ADT (p = 0.041). After a median of 66 months of follow-up, only one (2%) patient developed androgen-independent PC., Conclusions: Hormone-naïve patients who achieve and maintain a UD-PSA for at least one year during ADT may initiate IAD and anticipate a prolonged off-phase duration. Attainment of a UD-PSA on ADT may serve as an in vivo sensitivity test of a patient's tumor cell population, and allow for better selection of those best suited for IAD.

Late nausea and vomiting lasting 2-7 days occurs in 20%-68% of patients receiving cisplatin. We therefore studied the effects of oral metoclopramide given at doses of 20, 50, or 100 mg four times a day for 25 doses (7 days) beginning after cisplatin to determine the maximum tolerated dose (MTD) for prophylactic oral antiemetic regimens. Patients were stratified into younger (less than or equal to 30 yr old) and older (greater than 30 yr old) groups. Dose escalation was performed without or with concomitant oral diphenhydramine. For the younger group, the MTD for metoclopramide without diphenhydramine was less than 20 mg, and the MTD with diphenhydramine was 20 mg. For the older group, the MTD without diphenhydramine was 20 mg, and the MTD with diphenhydramine was 50 mg. Extrapyramidal reactions in the younger group and agitated depression in the older group were the major dose-terminating toxic effects. Patient acceptance of these regimens was excellent.

An open-label clinical trial was conducted to test the safety and efficacy of intravenous metoclopramide monohydrochloride in preventing chemotherapy-induced nausea and vomiting. Thirty-eight patients received a total of 83 assessable courses of chemotherapy with cisplatin alone or in combination with other cytotoxic agents. In 19 of 38 patients (50%) or 40 of 83 courses (48%), nausea or vomiting did not occur ("total protection") and in six of 38 patients (16%) or 19 of 83 courses (23%), emesis occurred one of two times ("major protection"). Thus, 25 of 38 patients (66%) receiving 59 of 83 courses (71%) of cisplatin-containing chemotherapy attained either total or major antiemetic protection with metoclopramide. In those patients who received multiple courses of chemotherapy, antiemetic protection afforded by metoclopramide remained unabated. At this dosage, the drug was well tolerated with minimal side effects. Intravenous metoclopramide is consistently effective in preventing emesis associated with cisplatin when used either alone or in combination with other cancer chemotherapy agents that are in themselves emetogenic.

Although cisplatin may have intrinsic activity against astrocytoma, limited penetration into the central nervous system may severely curtail delivery of adequate amounts of drug to the tumor. In an attempt to increase the dose of delivered drug without markedly increasing toxicity, cisplatin was administered by 5-day continuous intravenous infusion at a dose of 28 mg/m2/day (total dose 140 mg/m2) to 15 evaluable patients (5 with astrocytoma Grade III and 10 with astrocytoma Grade IV). Median age was 39 years, median Karnofsky Performance Status was 80%, and all patients had been previously treated with other modalities. One patient (7%) achieved Partial Response as demonstrated by increased strength of paretic extremities, increased Karnofsky Performance Status, and decrease of enhancing tumor mass on CT scan. Although nephrotoxicity was minimal, nausea and vomiting (usually mild) was seen in 14 patients. Myelosuppression was also common (anemia in 7 patients, leukopenia in 4 patients and thrombocytopenia in 3 patients). Ototoxicity was seen in 5 patients and may represent a combined modality toxicity with prior cranial radiotherapy. Routes and schedules which allow a higher peak serum concentration of cisplatin (such as subselective intracerebral artery infusion) may be necessary to achieve greater central nervous system drug penetration and to maximally exploit cisplatin in the treatment of astrocytoma.