Pharmacokinetic and pharmacodynamic considerations for the current chronic constipation treatments.

INTRODUCTION: Chronic constipation is a frequent condition often treated pharmacologically. The laxatives available belong to very different pharmacologic groups. AREAS COVERED: This is a short but comprehensive review of the pharmacology, efficacy and safety of currently available laxatives for chronic constipation. Pertinent publications were retrieved from reference lists of publications and by literature searches via PubMed, lastly performed in November 2012. EXPERT OPINION: The most relevant laxative groups are the older representatives osmotic salts, sugars and sugar alcohols, macrogol, anthraquinones, diphenolic laxatives or diphenyl methanes (bisacodyl and sodium picosulfate) and the newer compounds prucalopride, lubiprostone and linaclotide. For all of these laxatives efficacy has been shown in controlled trials. Electrolyte losses do not occur when laxatives are given in therapeutic doses (rare exceptions with phosphate salts and salinic laxatives). The older laxatives are also safe regarding teratogenicity, abortion and lactation. For the newer compounds no respective data are available as yet. It is questionable whether the newer compounds offer advantages over the older ones. Unfortunately, comparative trials are lacking.