Can Citracal (calcium citrate) cause constipation, particularly in older adults or individuals with a history of gastrointestinal issues?

Citracal (Calcium Citrate) and Constipation

Citracal (calcium citrate) does not cause constipation more than placebo in healthy individuals, though calcium carbonate formulations may increase gastrointestinal side effects including constipation.

Evidence on Calcium Supplementation and Constipation

The relationship between calcium supplements and constipation depends heavily on the formulation:

• Calcium citrate (Citracal) and calcium phosphate do not affect stool frequency or form in healthy women when providing 500 mg/day of elemental calcium 1
• In an 8-week randomized, double-blind crossover study, stool frequency remained stable at 1.3 stools/day across baseline, calcium carbonate, calcium phosphate, and washout periods 1
• Approximately 34-37% of participants experienced stools indicating slow transit (Bristol Stool Form Scale 1-2) during all periods, including baseline, suggesting no worsening with calcium supplementation 1

Calcium Carbonate vs. Calcium Citrate

Calcium carbonate is more likely to cause gastrointestinal adverse events than calcium citrate:

• Self-reported gastrointestinal adverse events (including constipation, excessive abdominal cramping, bloating, and upper GI symptoms) occurred in 14.1% of calcium-supplemented patients versus 10.0% on placebo (RR 1.43,95% CI 1.28-1.59, p < 0.001) 2
• Adjudicated functional GI hospitalizations were significantly higher with calcium supplementation: 6.8% versus 3.6% placebo (RR 1.92,95% CI 1.21-3.05, p = 0.006) 2
• These studies primarily evaluated calcium carbonate, not calcium citrate 2

Special Considerations for Older Adults

Older adults with normal bowel habits are unlikely to experience constipation from calcium supplementation:

• Older adults (mean age 69.7 years) maintained normal stool frequency of 1.63 stools/day with no change when consuming fortified foods 3
• The prevalence of constipation in older adults is more related to other factors including medications (NSAIDs, anticholinergics), reduced mobility, and inadequate hydration 4

Hypercalcemia Context

Constipation associated with calcium is primarily related to hypercalcemia, not supplementation at recommended doses:

• Chronic constipation in primary hyperparathyroidism patients correlates with higher serum calcium levels (p < 0.001) and ionized calcium (p < 0.001) 5
• The prevalence of constipation in hyperparathyroid patients decreased from 32.7% (1970-1989) to 21.8% (2006-2009) as calcium levels decreased (p < 0.05) 5
• Constipation appears associated with disease severity rather than calcium supplementation per se 5

Clinical Recommendations

For patients concerned about constipation:

• Recommend calcium citrate (Citracal) over calcium carbonate as it has better gastrointestinal tolerability 1
• Ensure adequate hydration, as this is critical for preventing constipation regardless of calcium supplementation 6
• If constipation develops, first-line treatment is polyethylene glycol (PEG) with strong recommendation and moderate certainty evidence 7, 8
• Consider fiber supplementation (particularly psyllium) for mild constipation, though this should be combined with adequate hydration 6

Common Pitfalls to Avoid

• Do not assume all calcium supplements are equally constipating - calcium citrate has better GI tolerability than calcium carbonate 1, 2
• Do not attribute constipation to calcium supplementation without considering other medications - NSAIDs, anticholinergics, and opioids are more likely culprits in older adults 4
• Do not use magnesium oxide as a laxative in patients with any degree of renal insufficiency if constipation does develop 6, 7