Myclausen: Uses, Dosage & Side Effects
An immunosuppressant containing mycophenolate mofetil for the prevention of organ transplant rejection in kidney, heart, and liver transplant recipients
Myclausen (mycophenolate mofetil) is a prescription immunosuppressant used to prevent organ rejection after kidney, heart, or liver transplantation. It belongs to a class of medications known as inosine monophosphate dehydrogenase (IMPDH) inhibitors, which work by selectively suppressing the proliferation of T and B lymphocytes — the immune cells primarily responsible for transplant rejection. Myclausen is always used in combination with other immunosuppressive agents, typically ciclosporin and corticosteroids. Mycophenolate mofetil is listed on the WHO Model List of Essential Medicines and has been a cornerstone of transplant immunosuppression protocols worldwide since its original approval. This guide covers dosage, side effects, drug interactions, warnings, and storage based on international clinical guidelines.
Quick Facts: Myclausen
Key Takeaways
- Myclausen (mycophenolate mofetil) is an essential immunosuppressant used to prevent organ rejection after kidney, heart, or liver transplantation, always in combination with ciclosporin and corticosteroids.
- The active metabolite mycophenolic acid (MPA) selectively inhibits lymphocyte proliferation by blocking the de novo purine synthesis pathway, providing targeted immunosuppression with less impact on other rapidly dividing cells.
- Myclausen must NOT be used during pregnancy due to a high risk of congenital malformations and spontaneous abortion; effective contraception is mandatory before, during, and for 6 weeks after stopping treatment.
- Common side effects include gastrointestinal symptoms (diarrhea, nausea, vomiting), infections, and blood disorders (anemia, leukopenia); regular blood monitoring is essential throughout treatment.
- Several important drug interactions exist, including reduced absorption with aluminium/magnesium antacids, decreased efficacy with cholestyramine and rifampicin, and live vaccines must be avoided during treatment.
What Is Myclausen and What Is It Used For?
Myclausen contains the active substance mycophenolate mofetil (MMF), a prodrug that is rapidly converted in the body to its active form, mycophenolic acid (MPA). MPA was originally derived from Penicillium species fungi and has been recognized for its immunosuppressive properties since the 1990s. Mycophenolate mofetil was first approved by the U.S. Food and Drug Administration (FDA) in 1995 under the brand name CellCept and has since become one of the most widely prescribed immunosuppressive agents in transplant medicine worldwide. Myclausen is a generic formulation of mycophenolate mofetil that is bioequivalent to the originator product.
The mechanism of action of Myclausen is highly selective and clinically relevant. MPA is a potent, selective, non-competitive, and reversible inhibitor of inosine monophosphate dehydrogenase (IMPDH), specifically the type II isoform that is predominantly expressed in activated lymphocytes. IMPDH is a critical enzyme in the de novo biosynthesis pathway of guanosine nucleotides, which are essential building blocks for DNA and RNA synthesis. While most cell types in the body can synthesize guanosine nucleotides through both the de novo pathway and an alternative salvage pathway, T and B lymphocytes are uniquely dependent on the de novo pathway for their proliferation. By blocking IMPDH type II, MPA selectively inhibits the proliferation of T and B lymphocytes without significantly affecting other rapidly dividing cell populations such as intestinal epithelial cells or bone marrow cells (which rely more heavily on the salvage pathway). This selectivity for lymphocytes is what makes mycophenolate mofetil a cornerstone of modern transplant immunosuppression.
In addition to inhibiting lymphocyte proliferation, MPA exerts several other immunomodulatory effects that contribute to its clinical efficacy. It inhibits the glycosylation and expression of adhesion molecules on lymphocytes, thereby reducing the recruitment of immune cells to sites of inflammation and graft rejection. MPA also suppresses antibody formation by B lymphocytes, which helps prevent antibody-mediated rejection of the transplanted organ. Furthermore, MPA inhibits the proliferation of arterial smooth muscle cells, which may provide a protective effect against the development of transplant vasculopathy, a form of chronic rejection that affects the blood vessels of transplanted organs.
Myclausen is indicated for the prophylaxis of acute transplant rejection in patients receiving allogeneic kidney, heart, or liver transplants. It is always used as part of a combination immunosuppressive regimen, typically alongside ciclosporin (a calcineurin inhibitor) and corticosteroids. This triple-therapy approach targets different components of the immune response, providing more effective prevention of rejection while allowing lower doses of each individual drug, thereby reducing the severity of side effects associated with any single agent.
The clinical evidence supporting mycophenolate mofetil in transplantation is extensive. Three landmark phase III randomized controlled trials established the efficacy of MMF in kidney transplantation: the U.S. Renal Transplant Study, the European Mycophenolate Mofetil Cooperative Study, and the Tricontinental Study. These trials demonstrated that MMF, when combined with ciclosporin and corticosteroids, significantly reduced the incidence of biopsy-proven acute rejection episodes in the first 6 months after kidney transplantation compared with placebo or azathioprine. Subsequent studies in heart and liver transplant recipients confirmed similar benefits. Long-term follow-up data have shown that MMF-based regimens are associated with improved graft survival, reduced chronic allograft nephropathy, and better long-term outcomes compared with older immunosuppressive agents.
Mycophenolate mofetil is included on the World Health Organization (WHO) Model List of Essential Medicines, recognizing it as one of the most effective and safe medications needed in a health system. It is considered a fundamental component of immunosuppressive therapy for solid organ transplant recipients worldwide.
What Should You Know Before Taking Myclausen?
Contraindications
Myclausen is contraindicated in patients with known hypersensitivity to mycophenolate mofetil, mycophenolic acid, or any of the excipients in the formulation. Hypersensitivity reactions to mycophenolate mofetil have been reported, including anaphylactic reactions. If a serious allergic reaction occurs, treatment should be discontinued and appropriate medical intervention initiated.
Myclausen must not be used during pregnancy unless no suitable alternative treatment is available to prevent transplant rejection. Mycophenolate mofetil is a known human teratogen. Data from the National Transplantation Pregnancy Registry (NTPR) and published literature have demonstrated that exposure to mycophenolate mofetil during pregnancy is associated with an increased risk of congenital malformations, including external ear abnormalities (microtia, anotia), cleft lip and palate, cardiac defects (atrial and ventricular septal defects), distal limb anomalies, esophageal atresia, renal malformations, and central nervous system anomalies. The overall rate of congenital malformations in pregnancies exposed to mycophenolate mofetil is approximately 23–27%, compared with 2–3% in the general population. Additionally, the rate of spontaneous abortion in exposed pregnancies is approximately 45–49%.
Myclausen must also not be started in women of childbearing potential without a negative pregnancy test result and confirmation that effective contraception is being used. Breastfeeding is contraindicated during Myclausen treatment because it is not known whether mycophenolate mofetil or its metabolites are excreted in human breast milk, and the potential for serious adverse reactions in nursing infants cannot be excluded.
Warnings and Precautions
Mycophenolate mofetil causes birth defects and miscarriages. Women must NOT become pregnant during treatment. Two reliable forms of contraception must be used simultaneously before starting treatment, during treatment, and for 6 weeks after stopping. A negative pregnancy test is required before initiating therapy. If pregnancy occurs, stop the medication immediately and consult your transplant specialist.
As an immunosuppressant, Myclausen increases the susceptibility to infections, including opportunistic infections, fatal infections, and sepsis. The risk of infections is related to the overall intensity of immunosuppression. Patients should be advised to report any signs of infection promptly. Particularly important infections to be aware of include:
- BK virus nephropathy: Cases of BK virus-associated nephropathy have been reported in patients receiving immunosuppressive therapy, including mycophenolate mofetil. This infection can lead to significant kidney dysfunction and graft loss. Monitoring for BK viremia is recommended.
- Progressive multifocal leukoencephalopathy (PML): Rare cases of JC virus-associated PML have been reported. PML is a serious brain infection that can be fatal or result in severe disability. If neurological symptoms develop, consider PML in the differential diagnosis.
- Cytomegalovirus (CMV): The risk of CMV viremia and disease is increased, particularly in the early post-transplant period. CMV prophylaxis or preemptive therapy should be considered according to institutional protocols.
- Reactivation of hepatitis B or C: Reactivation has been reported in patients receiving immunosuppressive agents. Appropriate screening and monitoring are recommended.
Patients receiving immunosuppressive regimens involving combinations of drugs, including mycophenolate mofetil, are at increased risk of developing lymphomas and other malignancies, particularly of the skin. The risk of malignancy appears to be related to the intensity and duration of immunosuppression. Patients should minimize exposure to sunlight and ultraviolet light by wearing protective clothing and using sunscreen with a high sun protection factor (SPF).
Pure red cell aplasia (PRCA) has been reported in patients treated with mycophenolate mofetil in combination with other immunosuppressive agents. The mechanism by which mycophenolate mofetil causes PRCA is not known. PRCA may be reversible with dose reduction or discontinuation of mycophenolate mofetil. Changes to Myclausen therapy should only be undertaken under appropriate specialist supervision to minimize the risk of graft rejection.
Complete blood counts should be performed weekly during the first month of treatment, twice monthly during months 2 and 3, then monthly through the first year. If neutropenia develops (absolute neutrophil count <1.3 × 103/μL), dose interruption or reduction may be necessary. Never adjust your dose without consulting your transplant specialist.
Pregnancy and Breastfeeding
Mycophenolate mofetil is a potent human teratogen. Women of childbearing potential must use at least one, preferably two, complementary forms of reliable contraception simultaneously before beginning Myclausen therapy, during therapy, and for 6 weeks after discontinuation of therapy. It is recommended that two complementary forms of contraception be used because mycophenolate may reduce the effectiveness of hormonal contraceptives (see Drug Interactions section). Acceptable contraceptive methods include intrauterine devices (IUDs), barrier methods (condoms, diaphragms), and hormonal contraceptives. A pregnancy test with a sensitivity of at least 25 mIU/mL should be performed within 8–10 days before starting therapy and repeated after 8–10 days. Pregnancy tests should be repeated during routine follow-up visits.
Male patients or their female partners should also use effective contraception during treatment and for at least 90 days after the last dose, as mycophenolate mofetil is genotoxic and a small amount of mycophenolic acid has been detected in seminal fluid. The theoretical risk to the offspring is considered low, but caution is advised.
Breastfeeding is contraindicated during treatment with Myclausen. It is not known whether mycophenolate mofetil is excreted in human breast milk. Given the potential for serious adverse reactions in nursing infants, including immunosuppression, a decision should be made whether to discontinue breastfeeding or to discontinue the drug, taking into account the importance of the drug to the mother.
Elderly Patients
Elderly patients (65 years and older) may be at increased risk of adverse events compared with younger patients. This includes a higher susceptibility to infections, gastrointestinal bleeding, and pulmonary edema. No specific dose adjustment is recommended for elderly patients, but they should be monitored more closely for adverse effects. The benefits of treatment must be carefully weighed against the potential risks in this age group.
How Does Myclausen Interact with Other Drugs?
Major Interactions
Several drug interactions with Myclausen are considered clinically significant and may require dose adjustment, altered administration timing, or avoidance of concurrent use. The most important of these interactions are detailed below and summarized in the interaction table.
Cholestyramine: Cholestyramine, a bile acid sequestrant, significantly reduces MPA exposure by approximately 40% by interrupting the enterohepatic recirculation of MPA glucuronide (MPAG). Following oral administration of mycophenolate mofetil, MPA is glucuronidated in the liver to form MPAG, which is excreted in bile. In the intestine, MPAG is converted back to MPA by gut bacteria, which is then reabsorbed (enterohepatic recirculation). Cholestyramine binds MPAG in the intestine and prevents this recirculation. Concurrent use of cholestyramine is not recommended unless clinically necessary, and therapeutic drug monitoring of MPA should be considered.
Rifampicin: Rifampicin is a potent inducer of uridine diphosphate-glucuronosyltransferase (UGT) enzymes, which are responsible for the glucuronidation of MPA. Concurrent administration of rifampicin can reduce MPA exposure by approximately 18–70%, depending on the study and population. This interaction can significantly diminish the immunosuppressive effect of Myclausen and increase the risk of transplant rejection. If rifampicin must be used, close monitoring of MPA levels and clinical response is essential, and dose adjustment may be required.
Live vaccines: Live attenuated vaccines should not be administered to patients receiving immunosuppressive therapy with Myclausen. Vaccination with live vaccines may be less effective due to the impaired immune response, and there is a theoretical risk of vaccine-associated infection in immunosuppressed patients. Examples of live vaccines to avoid include measles, mumps, rubella (MMR), varicella, oral polio, yellow fever, and live intranasal influenza vaccines. Inactivated vaccines may be administered, although the immune response may be diminished.
Other Important Interactions
Antacids (aluminium and magnesium hydroxides): Antacids containing aluminium and magnesium hydroxides reduce the absorption of mycophenolate mofetil, resulting in a decrease in MPA area under the curve (AUC) of approximately 17%. While not as dramatic as some other interactions, this can be clinically relevant in transplant patients where maintaining adequate immunosuppressive levels is critical. Myclausen and antacids should be taken at least 2 hours apart.
Proton pump inhibitors (PPIs): Pantoprazole, lansoprazole, and other PPIs may reduce the absorption of mycophenolate mofetil by altering gastric pH, leading to reductions in MPA exposure of up to 35%. This interaction is particularly relevant for enteric-coated mycophenolate sodium formulations but can also affect mycophenolate mofetil. If a PPI is necessary, consider therapeutic drug monitoring of MPA.
Aciclovir/Valaciclovir and Ganciclovir/Valganciclovir: MPA glucuronide (MPAG) and aciclovir (or ganciclovir) compete for renal tubular secretion. When used together, plasma concentrations of both MPAG and the antiviral agent may increase. This is particularly important in patients with renal impairment, where accumulation can occur more readily. Monitor renal function and blood counts closely when these drugs are used concurrently.
Ciclosporin: Ciclosporin A inhibits the enterohepatic recirculation of MPA, and switching from ciclosporin to another immunosuppressant (e.g., tacrolimus or sirolimus) that does not affect enterohepatic recirculation can lead to a significant increase in MPA exposure. Conversely, if ciclosporin is discontinued, MPA levels may rise, potentially requiring a dose reduction of Myclausen. Therapeutic drug monitoring is strongly recommended during any changes to the concomitant immunosuppressive regimen.
Oral hormonal contraceptives: A pharmacokinetic interaction study demonstrated that mycophenolate mofetil did not significantly alter the pharmacokinetics of the oral contraceptive containing ethinylestradiol and levonorgestrel. However, because of the theoretical risk and because MMF can cause gastrointestinal disturbances that may impair oral contraceptive absorption, it is recommended that women of childbearing potential use an additional barrier method of contraception in combination with hormonal contraceptives.
| Interacting Drug | Effect on MPA | Clinical Significance | Recommendation |
|---|---|---|---|
| Cholestyramine | Decreases MPA AUC by ~40% | Major | Avoid concurrent use; monitor MPA levels |
| Rifampicin | Decreases MPA AUC by 18–70% | Major | Monitor MPA levels closely; dose adjustment likely needed |
| Live vaccines | N/A | Major | Contraindicated; use inactivated vaccines |
| Antacids (Al/Mg) | Decreases MPA AUC by ~17% | Moderate | Separate administration by ≥2 hours |
| Proton pump inhibitors | May decrease MPA AUC by up to 35% | Moderate | Consider MPA therapeutic drug monitoring |
| Aciclovir / Ganciclovir | Increased levels of both drugs | Moderate | Monitor renal function and blood counts |
| Ciclosporin A | Reduces MPA via EHC inhibition | Moderate | Monitor MPA when switching calcineurin inhibitors |
| Oral contraceptives | Potentially reduced efficacy | Moderate | Use additional barrier contraception method |
What Is the Correct Dosage of Myclausen?
Adults
The recommended dosage of Myclausen varies by transplant type and is based on pivotal clinical trials that established the optimal balance between efficacy (prevention of acute rejection) and tolerability (minimization of side effects). Treatment should be initiated as soon as possible after transplantation, ideally within 72 hours, and should always be prescribed by a transplant specialist experienced in immunosuppressive therapy.
Kidney Transplant Recipients
The recommended dose is 1 g (two 500 mg tablets) twice daily, for a total daily dose of 2 g. In the landmark clinical trials, the 2 g/day dose was found to provide the optimal balance between efficacy and safety, with doses of 3 g/day offering no significant additional benefit in preventing acute rejection while being associated with a higher incidence of adverse effects. Treatment should be started within 72 hours of transplant surgery.
Heart Transplant Recipients
The recommended dose is 1.5 g (three 500 mg tablets) twice daily, for a total daily dose of 3 g. Heart transplant recipients require a higher dose than kidney transplant recipients because the immunological challenge of preventing cardiac allograft rejection is generally greater. Clinical trials demonstrated that this dose significantly reduced mortality and the need for treatment of rejection at 12 months post-transplant.
Liver Transplant Recipients
The recommended dose is 1.5 g (three 500 mg tablets) twice daily, for a total daily dose of 3 g. In the initial post-transplant period, intravenous mycophenolate mofetil may be administered if the patient is unable to take oral medication, and should be switched to oral Myclausen as soon as tolerated.
| Transplant Type | Single Dose | Frequency | Total Daily Dose |
|---|---|---|---|
| Kidney | 1 g (2 tablets) | Twice daily | 2 g |
| Heart | 1.5 g (3 tablets) | Twice daily | 3 g |
| Liver | 1.5 g (3 tablets) | Twice daily | 3 g |
Myclausen tablets should be swallowed whole with a glass of water and should not be crushed, cut, or chewed. The film coating serves both to protect the drug from gastric degradation and to protect the healthcare worker from potential exposure to the active substance, as mycophenolate mofetil has demonstrated teratogenic effects. The tablets should ideally be taken on an empty stomach (at least 1 hour before or 2 hours after meals), as food can reduce the peak plasma concentration of MPA by approximately 40%, although the total exposure (AUC) is not significantly affected. However, for patients with gastrointestinal intolerance, taking the tablets with food is acceptable if necessary to improve adherence.
Children
For pediatric kidney transplant recipients (aged 2 years and older), the recommended dose of mycophenolate mofetil is calculated based on body surface area (BSA): 600 mg/m2 twice daily, up to a maximum daily dose of 2 g. Pediatric dosing is typically available in oral suspension form (mycophenolate mofetil 200 mg/mL), as the 500 mg tablet may be too large for younger children. Children with a body surface area of 1.25–1.5 m2 may receive 750 mg twice daily (as tablets), and children with BSA >1.5 m2 may receive 1 g twice daily. Safety and efficacy in pediatric heart and liver transplant recipients have not been established.
Elderly
No specific dose adjustment is recommended for elderly patients (65 years and older). However, elderly patients may be more susceptible to adverse effects, particularly infections and gastrointestinal side effects, and should be monitored more closely. The recommended dose for elderly patients remains the same as for younger adults for each transplant indication. Renal function should be assessed regularly, as age-related decline in kidney function may affect the elimination of MPA metabolites.
Renal Impairment
In kidney transplant recipients experiencing severe chronic renal impairment (glomerular filtration rate <25 mL/min/1.73 m2) outside the immediate post-transplant period, doses greater than 1 g twice daily should be avoided, and patients should be carefully observed. No dose adjustment is necessary for patients with delayed graft function, although monitoring of MPA levels may be considered. In heart and liver transplant recipients with severe renal impairment, no specific data are available, but caution and close monitoring are advised.
Missed Dose
If you forget to take a dose of Myclausen, take it as soon as you remember. However, if it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not take a double dose to make up for a missed one. Consistent timing of doses is important to maintain stable blood levels of the active metabolite. If you frequently forget doses, discuss strategies with your transplant team, as inadequate immunosuppression increases the risk of transplant rejection.
Overdose
There is limited experience with overdose of mycophenolate mofetil. Reports of overdose have described symptoms consistent with the known adverse effect profile, primarily involving the gastrointestinal tract (nausea, vomiting, diarrhea) and hematological system (neutropenia, thrombocytopenia). In cases of overdose, general supportive measures should be employed. Although MPA is not efficiently removed by hemodialysis, the inactive metabolite MPAG can be removed at high plasma concentrations. Bile acid sequestrants such as cholestyramine may enhance the elimination of MPA by interrupting enterohepatic recirculation. If you suspect an overdose, contact your local poison control center or emergency services immediately.
What Are the Side Effects of Myclausen?
Like all immunosuppressive medications, Myclausen can cause side effects in some patients. The most frequently reported adverse reactions are related to the drug's mechanism of action: immunosuppression (leading to increased infection risk), bone marrow suppression (causing blood count abnormalities), and gastrointestinal effects. It is important to recognize that transplant recipients are treated with multiple immunosuppressive agents simultaneously, and it can be difficult to attribute specific side effects to any single drug. The following frequency classifications are based on pooled clinical trial data and post-marketing surveillance reports.
The side effects are categorized by frequency using the MedDRA convention: very common (≥1/10), common (≥1/100 to <1/10), uncommon (≥1/1,000 to <1/100), and rare (<1/1,000). Contact your healthcare provider if you experience any concerning symptoms.
Very Common
Affects more than 1 in 10 patients
- Diarrhea (often dose-related, may be severe)
- Nausea and vomiting
- Abdominal pain
- Leukopenia (low white blood cell count)
- Anemia
- Sepsis and opportunistic infections (CMV viremia, oral candidiasis)
- Urinary tract infections
- Herpes simplex and herpes zoster
Common
Affects 1 in 10 to 1 in 100 patients
- Thrombocytopenia (low platelet count)
- Gastrointestinal hemorrhage (stomach and intestinal bleeding)
- Peritonitis (inflammation of the abdominal lining)
- Pneumonia and bronchitis
- Skin rash and acne
- Headache and dizziness
- Insomnia, tremor, and anxiety
- Peripheral edema (swelling)
- Elevated liver enzymes
- Hyperglycemia (high blood sugar)
- Hypercholesterolemia (high cholesterol)
- Hypophosphatemia (low phosphate)
- Hypokalemia (low potassium)
- Joint pain (arthralgia)
- Renal function impairment
Uncommon
Affects 1 in 100 to 1 in 1,000 patients
- Lymphoma and lymphoproliferative disorder
- Skin carcinoma (squamous cell, basal cell)
- Pancytopenia (reduction of all blood cell types)
- Pancreatitis (inflammation of the pancreas)
- Colitis (including CMV colitis)
- Gastric and duodenal ulceration
- Intestinal perforation
- Severe infections including invasive aspergillosis
- Endocarditis (heart valve infection)
- Convulsions
Rare
Affects fewer than 1 in 1,000 patients
- Progressive multifocal leukoencephalopathy (PML)
- Pure red cell aplasia (PRCA)
- Agranulocytosis (severe absence of white blood cells)
- BK virus-associated nephropathy
- Parvovirus B19 infection
- Intestinal villous atrophy
- Hypogammaglobulinemia (in patients on concurrent immunosuppressants)
- Bronchiectasis (predominantly in pediatric patients)
- Pulmonary fibrosis
Gastrointestinal side effects, particularly diarrhea, are the most common reason for dose reduction or treatment discontinuation with mycophenolate mofetil. Diarrhea is often dose-related and may improve with dose adjustment. In clinical trials, approximately 30–36% of kidney transplant recipients receiving mycophenolate mofetil 2 g/day experienced diarrhea. Severe or persistent diarrhea should be reported promptly, as it may lead to dehydration and altered drug absorption, potentially affecting the levels of other immunosuppressive medications.
Hematological side effects, including leukopenia, anemia, and thrombocytopenia, reflect the drug's antiproliferative effects on rapidly dividing cell populations. Leukopenia (white blood cell count <4.0 × 103/μL) occurs in approximately 10–35% of patients and is usually manageable with dose reduction. Severe neutropenia (absolute neutrophil count <500/μL) is less common but requires prompt intervention, including possible dose interruption, use of granulocyte colony-stimulating factor (G-CSF), and evaluation for concurrent viral infections.
The increased risk of malignancy, particularly lymphoma and skin cancer, is a class effect of immunosuppressive therapy. In post-marketing experience, non-melanoma skin cancers have been reported with increased frequency in transplant recipients receiving mycophenolate mofetil. Patients should be counseled about the importance of sun protection, regular skin examinations, and prompt reporting of any suspicious skin lesions. The cumulative incidence of post-transplant lymphoproliferative disorder (PTLD) in clinical trials was approximately 1% within the first year.
Contact your doctor or seek emergency care immediately if you experience: signs of serious infection (fever, persistent sore throat, unusual bruising or bleeding), severe or bloody diarrhea, signs of PML (progressive weakness on one side of the body, visual changes, confusion), unexplained skin lumps or changes to existing moles, or signs of severe allergic reaction (swelling, difficulty breathing, rash).
How Should You Store Myclausen?
Proper storage of Myclausen is essential to maintain the stability and efficacy of the medication. The film-coated tablets should be stored at temperatures not exceeding 25°C (77°F). The tablets should be kept in their original packaging (blister pack or bottle) to protect them from moisture and light exposure. Do not remove tablets from the blister pack until immediately before administration.
Keep Myclausen out of the reach and sight of children. Given the teratogenic potential of mycophenolate mofetil, particular care should be taken to ensure that the medication is stored securely and cannot be accidentally accessed by children, pregnant women, or anyone who might inadvertently come into contact with the active substance. If a tablet is accidentally broken or crushed, avoid inhalation of the powder or direct contact with the skin or mucous membranes. If contact occurs, wash the affected area thoroughly with soap and water. If contact with the eyes occurs, rinse thoroughly with plain water.
Do not use Myclausen after the expiry date printed on the packaging. The expiry date refers to the last day of the stated month. Do not dispose of medicines via wastewater or household waste. Return any unused or expired medication to your pharmacy for appropriate disposal in accordance with local environmental regulations. This helps to protect the environment and prevents accidental exposure.
What Does Myclausen Contain?
The active ingredient in each Myclausen film-coated tablet is mycophenolate mofetil 500 mg. Mycophenolate mofetil is the 2-morpholinoethyl ester of mycophenolic acid, with a molecular formula of C23H31NO7 and a molecular weight of 433.50 g/mol. It is a white to off-white crystalline powder that is slightly soluble in water.
The excipients (inactive ingredients) in Myclausen film-coated tablets include:
- Tablet core: Microcrystalline cellulose, povidone K-30, croscarmellose sodium, and magnesium stearate
- Film coating: Polyvinyl alcohol, titanium dioxide (E171), macrogol/PEG 3350, talc, and indigo carmine aluminium lake (E132)
The film-coated tablets are typically lavender-blue in color, capsule-shaped, and debossed with identification markings. The tablets are supplied in PVC/aluminium blister packs. The film coating serves to protect the active substance from gastric acid and moisture, improve ease of swallowing, and protect healthcare workers from potential exposure to the powder during handling.
Myclausen does not contain gluten, lactose, or sucrose. Patients with specific dietary restrictions or allergies should consult the full patient information leaflet or their pharmacist if they have concerns about any of the excipients.
Frequently Asked Questions About Myclausen
Ideally, Myclausen tablets should be taken on an empty stomach — at least 1 hour before or 2 hours after a meal. Food can reduce the peak plasma concentration of the active metabolite MPA by approximately 40%, although the overall drug exposure (AUC) is not significantly affected. However, if you experience nausea or stomach upset, your doctor may advise taking the tablets with food to improve tolerability. The most important thing is to take the medication consistently at the same times each day and to follow your transplant team's specific instructions.
Myclausen is typically a lifelong medication after organ transplantation. Immunosuppressive therapy is necessary for as long as the transplanted organ is functioning, because the body's immune system will always recognize the transplanted organ as foreign and will attempt to reject it if immunosuppression is stopped. Your transplant team may adjust the combination and doses of immunosuppressive medications over time, but stopping all immunosuppression is almost never recommended. Never discontinue Myclausen without consulting your transplant specialist, as doing so significantly increases the risk of acute rejection and graft loss.
Myclausen is a generic formulation of mycophenolate mofetil, which was originally marketed under the brand name CellCept. Both products contain the same active substance (mycophenolate mofetil) at the same strength and have been demonstrated to be bioequivalent, meaning they produce essentially the same blood levels of the active metabolite in the body. Myclausen has been approved by regulatory authorities (including the EMA) based on bioequivalence studies confirming that it can be used interchangeably with CellCept. However, any switch between brands should be supervised by your transplant specialist, and therapeutic drug monitoring may be considered to ensure stable MPA levels.
Diarrhea is one of the most common side effects of mycophenolate mofetil and can affect up to 30–36% of patients. Mild diarrhea may improve as your body adjusts to the medication. However, if diarrhea is persistent, severe, or accompanied by blood, fever, or signs of dehydration, contact your transplant team promptly. Do NOT stop taking Myclausen on your own, as this could lead to transplant rejection. Your doctor may adjust the dose, split the dose differently throughout the day, or consider switching to an enteric-coated mycophenolate sodium formulation, which may cause fewer gastrointestinal side effects in some patients. Maintaining adequate fluid intake is important.
Live attenuated vaccines (such as MMR, varicella, yellow fever, live intranasal influenza, and oral polio vaccines) should NOT be given while taking Myclausen or other immunosuppressive medications. There is a risk that the weakened virus in live vaccines could cause infection in an immunosuppressed patient. Inactivated vaccines (such as influenza injection, pneumococcal, hepatitis B, and COVID-19 vaccines) can generally be given, although the immune response may be reduced, meaning the vaccines might be less effective. Your transplant team will advise you on the recommended vaccination schedule, which typically includes annual influenza vaccination and pneumococcal vaccination. Household contacts should also be appropriately vaccinated to provide indirect protection.
In animal studies, mycophenolate mofetil did not impair fertility at doses equivalent to clinical exposure. However, given the mechanism of action (inhibition of cell proliferation), there is a theoretical concern. Importantly, mycophenolate mofetil is a potent teratogen, meaning it causes birth defects. Women must not become pregnant during treatment, and effective contraception is mandatory. Male patients should use contraception during treatment and for 90 days after the last dose. If you are planning to start a family, discuss with your transplant specialist well in advance, as they may need to switch you to an alternative immunosuppressive agent that is safer during conception and pregnancy, such as azathioprine.
References
- European Medicines Agency (EMA). Myclausen — Summary of Product Characteristics. Last updated 2025. Available at: www.ema.europa.eu
- U.S. Food and Drug Administration (FDA). CellCept (mycophenolate mofetil) — Prescribing Information. Revised 2024. Available at: www.fda.gov
- Kidney Disease: Improving Global Outcomes (KDIGO) Transplant Work Group. KDIGO Clinical Practice Guideline for the Care of Kidney Transplant Recipients. Am J Transplant. 2009;9 Suppl 3:S1–S155. Updated 2024.
- Allison AC, Eugui EM. Mycophenolate mofetil and its mechanisms of action. Immunopharmacology. 2000;47(2–3):85–118. doi:10.1016/s0162-3109(00)00188-0
- Halloran PF. Immunosuppressive drugs for kidney transplantation. N Engl J Med. 2004;351(26):2715–2729. doi:10.1056/NEJMra033540
- World Health Organization (WHO). Model List of Essential Medicines — 23rd List, 2023. Geneva: WHO; 2023.
- European Mycophenolate Mofetil Cooperative Study Group. Placebo-controlled study of mycophenolate mofetil combined with cyclosporin and corticosteroids for prevention of acute rejection. Lancet. 1995;345(8961):1321–1325.
- Sollinger HW. Mycophenolate mofetil for the prevention of acute rejection in primary cadaveric renal allograft recipients. U.S. Renal Transplant Mycophenolate Mofetil Study Group. Transplantation. 1995;60(3):225–232.
- Tricontinental Mycophenolate Mofetil Renal Transplantation Study Group. A blinded, randomized clinical trial of mycophenolate mofetil for the prevention of acute rejection in cadaveric renal transplantation. Transplantation. 1996;61(7):1029–1037.
- Kobashigawa JA et al. A randomized active-controlled trial of mycophenolate mofetil in heart transplant recipients. Transplantation. 1998;66(4):507–515.
- International Society for Heart and Lung Transplantation (ISHLT). Guidelines for the care of heart transplant recipients. J Heart Lung Transplant. 2023.
- British National Formulary (BNF). Mycophenolate mofetil. Available at: bnf.nice.org.uk
Editorial Team
This article has been written and reviewed by the iMedic Medical Editorial Team, which includes specialists in transplant medicine, clinical pharmacology, and immunology.
Medical Writers
Licensed physicians with expertise in transplant medicine and clinical pharmacology
Medical Reviewers
Board-certified transplant specialists and clinical pharmacologists
Evidence Review
Based on EMA SmPC, FDA label, KDIGO, ISHLT, and WHO guidelines
Quality Standards
GRADE evidence framework, Level 1A systematic review evidence
All content follows the iMedic Editorial Standards and is regularly reviewed to ensure accuracy and currency. This article does not contain any commercially funded content or pharmaceutical company sponsorship.