A client is being discharged on oral iron supplements. Which instruction is most important to prevent the most common adverse effect?

Oral iron supplementation teaching:

Most common adverse effect: GI distress — nausea, constipation, stomach cramps; dark/black stools (expected, not a sign of GI bleeding unless bright red).

Managing gi effects: Take with small amount of food to reduce nausea (reduces absorption slightly but improves adherence); increase fluid and fibre intake; stool softener may be ordered; start at lower dose and increase gradually.

Maximising absorption: Vitamin C (ascorbic acid) significantly increases iron absorption — orange juice, tomato juice, or vitamin C supplement with the dose; avoid coffee, tea, milk, calcium supplements, antacids within 2 hours (inhibit absorption).

Different formulations: Ferrous sulphate (most common); ferrous gluconate (more expensive, gentler on GI).

Liquid form: Use a straw to prevent tooth staining.

Patient education: Expected black stools; expected mild GI upset initially; do not stop without notifying provider; takes 4-8 weeks to see improvement in fatigue/haemoglobin.