Management of opioid-induced constipation in pregnancy: a concise review with emphasis on the PAMORAs

What is known and objective: Opioid-induced constipation (OIC) is one of the most common opioid-induced adverse effects. Pregnancy also predisposes to bowel dysfunctions due to the associated endocrine changes. Pregnant women are thus at greater risk of OIC. We review the non-pharmacologic and pharmacologic treatment options as a guide for achieving a clinically optimal strategy for the management of OIC during pregnancy. Methods: The published literature was searched for current therapeutic options, including non-pharmacologic dietary modifications, laxatives, and the peripherally acting mu-opioid receptor antagonists (PAMORAs). Each was assessed for efficacy and safety, particularly as they relate to pregnancy. Results and discussion: Non-pharmacologic approaches such as dietary change are generally safe, but generally insufficient when used alone to control OIC in pregnancy. Laxatives (bulking, osmotic, stimulant) can be effective, but have potential adverse effects that might be particularly troublesome during pregnancy (e.g. electrolyte disturbances, dehydration, abdominal pain, and pulmonary oedema or hypermagnesaemia in the extreme). PAMORAs, which attenuate OIC without affecting opioid-induced analgesia, have been associated with only minimal side effects during the clinical studies to date. What is new and conclusions: Conventional non-pharmacologic and pharmacologic options for the management of OIC in pregnancy are often suboptimal due to insufficient efficacy or adverse effects particularly troublesome during pregnancy. The PAMORA strategy appears to provide a safe and effective new option superior to conventional therapies for the management of OIC during pregnancy.