Immunosuppressive medicines
Immunosuppressants are medicines that help calm or reshape the immune system so it stops attacking platelets. They are usually used when first line treatments (like corticosteroids or IVIg) and second line treatments (like TPO RAs) haven’t worked well enough, or when a longer term treatment option is needed.
These medicines can be effective for people with persistent or chronic ITP, especially when the immune system is strongly involved in platelet destruction.
Medications included
Rituximab
Azathioprine
Mycophenolate mofetil (MMF)
Ciclosporin
Sirolimus
Hydroxychloroquine
Dapsone
Danazol
When immunosuppressants are used
Immunosuppressants are usually considered when:
- Steroids cannot be continued or cause significant side effects
- TPO RAs or splenectomy are not suitable or not preferred
- A longer term treatment is needed to maintain safe platelet levels
- A person has autoimmune features or other immune related conditions
- Combination therapy is needed in more complex or refractory ITP
These medicines may be used alone or combined with other treatments, depending on the individual situation.
How they work
Immunosuppressants work by:
- Reducing immune activity, so the body produces fewer antibodies that target platelets
- Modifying immune pathways, helping the immune system become less reactive
- Reducing inflammation, which can help stabilise platelet levels
- In the case of rituximab, targeting B cells (the cells that make antibodies)
Because they work on the immune system, these medicines often take weeks to months to show full benefit.
What to expect
- Many of these medicines are usually taken long term, with the exception of Rituximab
- Some are tablets (azathioprine, MMF, ciclosporin, sirolimus, hydroxychloroquine, dapsone, danazol)
- Rituximab is given as an infusion
- Regular blood tests are needed to monitor:
- Blood counts
- Liver and kidney function
- Immune markers
- It may take 4–12 weeks to see improvement
- Some people respond well; others may need to switch medicines
Your doctor will work with you to find the safest and most effective option.
Side effects
Side effects vary depending on the medicine, but may include:
- Increased risk of infections
- Nausea or stomach upset
- Liver or kidney test changes
- Skin changes or sensitivity
- Fatigue
- Hormonal effects (Danazol)
- Anaemia or haemolysis (Dapsone)
Your doctor will monitor for side effects and adjust treatment if needed.
Adults, Children and in Pregnancy
Adults
- Immunosuppressants are commonly used in adults with persistent or chronic ITP
- Rituximab is often used when a steroid sparing option is needed
- Some medicines (like Danazol) are used only in selected adults
Children
- Used less often in children
- May be considered in chronic or refractory cases under specialist care
- Rituximab and MMF are the most commonly used in paediatrics
Pregnancy
- Some immunosuppressants are not safe in pregnancy
- Others (like azathioprine) may be used under specialist guidance
- Rituximab is generally avoided unless absolutely necessary
Pregnancy planning should always be discussed before starting these medicines.
Other Considerations
These points help patients understand the practical aspects of immunosuppressant treatment:
- Infection risk may be higher — good hygiene and prompt treatment of illness are important
- Vaccinations may need to be updated before starting treatment
- Regular monitoring is essential to ensure safety
- Some medicines interact with:
- Blood pressure medications
- Antibiotics
- Antifungals
- Hormonal therapies
- Rituximab may reduce vaccine effectiveness for several months
- Dapsone requires testing for G6PD deficiency before use
- Danazol is not suitable for everyone and requires careful monitoring
These medicines are usually managed by a haematologist with experience in ITP.