METHODS: A systematic electronic literature search of PubMed, Embase, the Cochrane Library and Science Direct was conducted for the period 1995-2019. In these databases, search terms describing hypokalaemia and cardiotoxicity were combined with the term laxative use.
RESULTS AND DISCUSSION: Over the 23 years, 27 incidents were identified in 12 countries. There were 19 female and eight male patients, with ages ranging from 1 month to 93 years. The frequency of reported cases according to severity was the following: severe hypokalaemia 48%, moderate hypokalaemia 44.4% and mild hypokalaemia 7.4%. In 70% of patients, the effect of laxative on the heart was typical hypokalaemic electrographic changes, 7.4% showed abnormal changes in cardiac rhythm, whereas in 18.5%, the cardiotoxicity observed was a very serious kind. Two patients died due to severe cardiac effects.
WHAT IS NEW AND CONCLUSION: The laxatives-along with the involvement of some other contributing factors-caused mild-to-severe hypokalaemic cardiotoxicity. These factors were non-adherence of the patient to the recommended dosage, laxative abuse, drug-drug and drug-disease interactions, non-potassium electrolyte imbalances and the use of herbal laxatives. We recommend that laxatives and aggravating factors should be taken into account in the assessment of patients with suspected hypokalaemic cardiotoxicity.
METHODS: Women at 28-32 weeks' gestation attending antenatal clinic for routine care were screened using the Rome IV chronic constipation criterion. Eligible women were approached and consented. Participants were randomized to oral polyethylene glycol (10 g/day) or lactulose (10 g/day) for 4 weeks. A bowel movement diary was kept and outcomes using the Patient Assessment of Constipation Symptoms questionnaire (PAC-SYM), Patient Assessment of Constipation Quality of Life questionnaire (PAC-QoL) and Bristol Stool Form Scale (BSFS), which were evaluated at the start and end of the four-week period. Relative risks (RR) were determined for the coprimary outcomes of complete spontaneous bowel movement (CSBM) and PAC-SYM mean score improvement (decrease in score of >1 from the baseline).
RESULTS: A total of 4323 women underwent screening, of which 780 fulfilled the Rome IV criterion, and 360 consented to participate (180 randomized to PEG and lactulose, respectively). Data from 247 women who completed the study were analyzed. CSBM was achieved in 107/124 (86.3%) versus 102/123 (82.9%) (RR 1.04, 95% CI: 0.93-1.16, P = 0.464) for PEG and lactulose trial arms, respectively. PAC-SYM mean score improvement was 62/118 (52.5%) in the PEG arm versus 44/118 (37.3%) in the lactulose arm (RR 1.40, 95% CI: 1.05-1.88). Of secondary outcomes, a significant difference was found in favor of PEG, with respect to PAC-SYM abdominal symptoms subscale, normal stool versus loose stool consistency and side effects of vomiting and diarrhea. After controlling for parity, baseline PAC-SYM, PAC-QoL scores, characteristics different at baseline, only diarrhea and loose stools remained significant.
CONCLUSION: Both PEG 4000 and lactulose are effective laxatives in pregnancy with similar performance after adjusted analysis. Diarrhea and loose stools are less frequently reported with PEG.