Mycophenolate mofetil is a prodrug of mycophenolic acid, a powerful immunosuppressive medication.
What is mycophenolate mofetil?
Mycophenolate mofetil is a prodrug of mycophenolic acid, which is a powerful immunosuppressive drug. Another kind of mycophenolic acid utilized in clinical practice is enteric-coated mycophenolate sodium.
Who uses mycophenolate mofetil?
Mycophenolate mofetil is an immunosuppressant that has been approved to prevent the rejection of solid organ transplants (kidney, liver, and heart).
Mycophenolate mofetil is often used off-label in dermatology.
- Good evidence for a beneficial effect
- Immunoblots disorders such as bullous pemphigoid and pemphigus vulgaris.
- Weak evidence and/or inconsistent response
- Atopic dermatitis, psoriasis
- Connective tissue diseases
- Vitiligo, small vessel vasculitis, lichen planus and its variants, erythema multiforme, pyoderma gangrenosum, granulomatosis with polyangiitis, acute febrile neutrophilic dermatosis, and many other inflammatory dermatoses.
Contraindications and precautions with mycophenolate mofetil
- Allergy to the drug or its excipients
- Reported to cause spontaneous abortion, craniofacial malformations, cardiac malformations
- Women must use effective contraception starting four weeks before commencement, throughout treatment, and for six weeks after the last dose
- Men should use condoms during sexual intercourse throughout treatment and for 90 days after the last dose. Female partners of males treated with mycophenolate mofetil should also use effective contraception during their partner’s treatment and for 90 days after the partner’s last treatment dose.
- Peptic ulcer disease
- Liver disease
- Cardiopulmonary disease
- Live vaccines should be avoided
More about mycophenolate mofetil
Mechanism of action
- Reversible, selective, non-competitive inhibitor of the enzyme inosine monophosphate dehydrogenase (IMPDH)
- IMPDH is an important enzyme in the synthesis of purines
- Purine synthesis is essential for lymphocyte development and proliferation
- Blocking IMPDH inhibits T- and B-lymphocyte function
- Reduces lymphocyte proliferation, antibody formation, and cell-mediated immune response
Drug forms and dosing
Oral and injectable versions of mycophenolate mofetil are available.
In dermatology, a normal starting dose is 250 mg twice daily. If there is no improvement after one month of treatment, the dose can be increased in 500 mg increments up to 3 g per day.
Because mycophenolic acid is largely eliminated through the kidneys, dose reduction is recommended in patients with chronic renal problems.
Other immunosuppressive medicines are frequently used in conjunction with mycophenolate mofetil.
What are the benefits of mycophenolate mofetil?
- Oral administration available
- Wide therapeutic range
What are the disadvantages of mycophenolate mofetil?
- Clinical response is slow
- Regular blood test monitoring is required
- Contraception is necessary for both males and females taking mycophenolate mofetil
- Drug interactions
- Reduced mycophenolate blood level
- Iron and calcium supplements, antacids, proton pump inhibitors
- Antibiotics including penicillins, cephalosporins, sulphonamides, macrolides, metronidazole
- Increased mycophenolate blood level
- Salicylates, phenytoin
- Mycophenolate may increase the blood level of other drugs
- Antivirals eg, aciclovir
- Reduced mycophenolate blood level
What are the side effects and risks of mycophenolate mofetil?
Mucocutaneous side effects
- Mucocutaneous candidiasis is common
- Other skin infections — herpes varicella-zoster, atypical mycobacterial infection, tinea
- Hand dermatitis
- Cutaneous squamous cell carcinoma — with long-term use of combination immunosuppressants such as post-transplant
- Recommend sun protection with SPF 50+ sunscreen and UPF 50+ clothing.
Common side effects
- Nausea and vomiting, diarrhoea or constipation, abdominal cramps.
- Bacterial — urinary tract infection, pneumonia
- Viral — cytomegalovirus (CMV), BK virus.
Uncommon but potentially serious side effects
- Opportunistic infections
- Bone marrow suppression — dose-related; reported in 5–9%; usually mild and reversible
- Epstein-Barr virus-associated lymphoproliferative disorders with long-term use in combination with other immunosuppressants such as post-transplant.
Monitoring during treatment
Before starting treatment
- Test for latent tuberculosis, hepatitis B and C
- Check immunity status eg, measles and varicella
- Baseline blood tests
- Regular full blood count – weekly for the first month then every two weeks for two months, and monthly for the rest of the first year
- Liver and kidney function tests — every 2–4 weeks until dose is stabilized and then every 2–3 months
- Pregnancy test if appropriate in the first week
- Regular skin checks — patient should practice self skin examination
Discontinuation of treatment
Mycophenolate mofetil should be ceased if pregnancy occurs or:
- Lymphocyte count < 1.0×109/L
If the suppression of the bone marrow is minor, it usually improves when the dose is reduced or the mycophenolate mofetil is stopped.
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