While gastrointestinal side effects are common with ferrous sulfate, Kirsty does seem to be having a particularly bad reaction. One thing she could try is taking the tablets after meals, instead of beforehand, as the presence of food in the stomach should help ease the nausea. Reducing the dose isn’t really an option, as she is being treated for iron deficiency anaemia rather than being on the tablets to prevent the condition occurring.

If Kirsty is really struggling, she should return to her doctor and explain the issues she is having. Iron supplements come in many different salt forms (ferrous gluconate and ferrous fumarate are among the most common, in addition to ferrous sulfate) and formulations, and changing to another product may resolve the side effects she is experiencing. It is important, however, to maintain the amount of elemental iron she is receiving from the supplement, which a doctor or pharmacist can check for her.

Kirsty also needs to know that this isn’t a quick fix – it can take three to four weeks for haemoglobin levels to return to normal, and a further three months for the iron stores to be replenished.