From the Guidelines
To manage constipation caused by iron supplementation, consider switching to a different iron formulation such as ferrous bisglycinate, which may cause less constipation than ferrous sulfate, as there is no substantial evidence that any one product is better than another in effectiveness or tolerance 1. When managing constipation due to iron supplementation, several strategies can be employed to alleviate symptoms.
- Increasing daily water intake to at least 8-10 glasses can help soften stool and improve bowel movements.
- Adding more fiber to the diet through fruits, vegetables, and whole grains can also help regulate bowel movements.
- Taking iron supplements with food can help reduce digestive side effects, though this may slightly decrease absorption.
- Over-the-counter stool softeners like docusate sodium (100-300 mg daily) or osmotic laxatives such as polyethylene glycol (17g in water daily) can provide relief.
- Regular physical activity also stimulates bowel movements. It is also important to note that taking iron more than once a day will not improve absorption but will increase side effects, including constipation, as levels of serum hepcidin increase in response to oral iron and remain increased for up to 48 hours 1. Certain dietary manipulations, such as taking iron with 80 mg ascorbic acid on an empty stomach, may improve iron absorption, but evidence supporting vitamin C administration to improve iron absorption is mixed and further study is needed to clarify the effectiveness of this practice 1. If constipation persists despite these measures, consulting a healthcare provider about adjusting the iron dose or trying a slow-release formulation may be necessary.
From the Research
Management of Constipation due to Iron Supplementation
To manage constipation caused by iron supplementation, several strategies can be employed:
- Increase dietary fiber intake, as it plays a crucial role in preventing and managing constipation in adults 2
- Consider using stimulant and/or osmotic laxatives, as well as intestinal secretagogues and/or prokinetic agents, guided by efficacy and cost 3
- For opioid-induced constipation, peripherally acting μ-opiate antagonists can be used 3
- Anorectal tests can be performed to evaluate for defecatory disorders in patients who do not respond to over-the-counter agents 3
Iron Supplementation and Constipation
Some iron supplements are more likely to cause constipation than others:
- Ferrous fumarate, ferrous sulfate, and ferrous bisglycinate are commonly used iron supplements, but they can have different side effect profiles 4
- Ferrous bisglycinate 25 mg iron/day may have a more favorable GI side effect profile compared to ferrous fumarate 40 mg iron/day and ferrous sulfate 50 mg iron/day 4
- Extended-release ferrous sulfate with mucoproteose appears to be one of the best-tolerated oral iron supplements, with a lower incidence of adverse effects, including gastrointestinal adverse effects 5
Treatment of Constipation
Psyllium is a effective treatment for chronic constipation:
- Psyllium is superior to docusate sodium for softening stools and increasing stool water content, and has greater overall laxative efficacy in subjects with chronic idiopathic constipation 6
- Psyllium can increase stool water weight, total stool output, and bowel movement frequency, making it a useful treatment option for constipation 6