• laxatives
• effectiveness

This paper summarises the research evidence presented in a recent issue of Effective Health Care on the effectiveness of the four main types of laxatives used in the treatment of constipation in adults.¹ The bulletin was based on two systematic reviews^2,3 (table 1) and on the additional randomised controlled trials (RCTs) identified since the publication (1997) of these reviews (tables 2 and 3).

Constipation is a common reason for GP consultations in adults. The UK National Survey of Morbidity in General Practice in England and Wales found consultations for constipation were particularly common among the very young and the very old.⁴ The prevalence is less than 10% in the UK general population,⁵ about 20% among older people living in the community,² and higher still among those living in nursing homes.⁶ About half of all patients admitted to specialist palliative care units report constipation, but about 75% of such patients will require laxatives.⁷ Laxatives are required by about 87% of terminally ill patients taking strong oral opioids, 74% of those on weak opioids, and 64% of those not receiving opioid analgesia.⁸ There also appear to be socioeconomic, sex, regional, and national differences in the prevalence of constipation.^2,9 Constipation adversely affects the quality of life of the sufferer¹⁰ and accounts for a significant proportion of the NHS drug bill.¹¹ At over £46 million per year in England, expenditure on the four main types of laxative (bulk, osmotic, stimulant, and softener) is higher than on hypnotics and anxiolytics such as benzodiazepines.¹²