Influence of green tea consumption on endoxifen steady-state concentration in breast cancer patients treated with tamoxifen

Background: Many cancer patients use additional herbs or supplements in combination with their anti-cancer therapy. Green tea—active ingredient epigallocatechin-3-gallate (EGCG)—is one of the most commonly used dietary supplements among breast cancer patients. EGCG may alter the metabolism of tamoxifen. Therefore, the aim of this study was to investigate the influence of green tea supplements on the pharmacokinetics of endoxifen; the most relevant active metabolite of tamoxifen. Methods: In this single-center, randomized cross-over trial, effects of green tea capsules on endoxifen levels were evaluated. Patients treated with tamoxifen for at least 3 months were eligible for this study. After inclusion, patients were consecutively treated with tamoxifen monotherapy for 28 days and in combination with green tea supplements (1 g twice daily; containing 300 mg EGCG) for 14 days (or vice versa). Blood samples were collected on the last day of monotherapy or combination therapy. Area under the curve (AUC0–24h), maximum concentration (Cmax) and minimum concentration (Ctrough) were obtained from individual plasma concentration–time curves. Results: No difference was found in geometric mean endoxifen AUC0–24h in the period with green tea versus tamoxifen monotherapy (− 0.4%; 95% CI − 8.6 to 8.5%; p = 0.92). Furthermore, no differences in Cmax (− 2.8%; − 10.6 to 5.6%; p = 0.47) nor Ctrough (1.2%; − 7.3 to 10.5%; p = 0.77) were found. Moreover, no severe toxicity was reported during the whole study period. Conclusions: This study demonstrated the absence of a pharmacokinetic interaction between green tea supplements and tamoxifen. Therefore, the use of green tea by patients with tamoxifen does not have to be discouraged

South African cardiovascular risk stratification guideline for non-cardiac surgery

The South African (SA) guidelines for cardiac patients for non-cardiac surgery were developed to address the need for cardiac risk assessment and risk stratification for elective non-cardiac surgical patients in SA, and more broadly in Africa. The guidelines were developed by updating the Canadian Cardiovascular Society Guidelines on Perioperative Cardiac Risk Assessment and Management for Patients Who Undergo Non-cardiac Surgery, with a search of literature from African countries and recent publications. The updated proposed guidelines were then evaluated in a Delphi consensus process by SA anaesthesia and vascular surgical experts. The recommendations in these guidelines are: 1. We suggest that elective non-cardiac surgical patients who are 45 years and older with either a history of coronary artery disease, congestive cardiac failure, stroke or transient ischaemic attack, or vascular surgical patients 18 years or older with peripheral vascular disease require further preoperative risk stratification as their predicted 30-day major adverse cardiac event (MACE) risk exceeds 5% (conditional recommendation: moderate-quality evidence). 2. We do not recommend routine non-invasive testing for cardiovascular risk stratification prior to elective non-cardiac surgery in adults (strong recommendation: low-to-moderate-quality evidence). 3. We recommend that elective non-cardiac surgical patients who are 45 years and older with a history of coronary artery disease, or stroke or transient ischaemic attack, or congestive cardiac failure or vascular surgical patients 18 years or older with peripheral vascular disease should have preoperative natriuretic peptide (NP) screening (strong recommendation: high-quality evidence). 4. We recommend daily postoperative troponin measurements for 48 - 72 hours for non-cardiac surgical patients who are 45 years and older with a history of coronary artery disease, or stroke or transient ischaemic attack, or congestive cardiac failure or vascular surgical patients 18 years or older with peripheral vascular disease, i.e. (i) a baseline risk >5% for MACE 30 days after elective surgery (if no preoperative NP screening), or (ii) an elevated B-type natriuretic peptide (BNP)/N-terminal-prohormone B-type natriuretic peptide (NT-proBNP) measurement before elective surgery (defined as BNP >99 pg/mL or a NT-proBNP >300 pg/mL) (conditional recommendation: moderate-quality evidence). Additional recommendations are given for the management of myocardial injury after non-cardiac surgery (MINS) and medications for comorbidities.The Global Surgery Fellowship grant.http://www.samj.org.zadm2022Anaesthesiolog