Mavenclad (cladribine): Uses, Side Effects, Interactions, Pictures, Warnings & Dosing – WebMD

Quick note before we dive in: This article is for general information only and is not a substitute for professional medical advice, diagnosis, or treatment. Always talk with your neurologist or other qualified healthcare professional before starting, stopping, or changing any medication, including Mavenclad.

What Is Mavenclad (Cladribine)?

Mavenclad (cladribine) is an oral prescription medication used to treat certain relapsing forms of multiple sclerosis (MS) in adults. That includes relapsing-remitting MS (RRMS) and active secondary progressive MS (SPMS). It is generally reserved for people whose MS has not responded well to, or who cannot tolerate, other disease-modifying therapies.

Unlike many MS treatments that require frequent injections or regular infusions, Mavenclad is taken in short courses over two years, followed by a treatment-free period. It belongs to a class of drugs known as immune reconstitution therapies, meaning it temporarily reduces certain immune cells and then allows the immune system to “rebuild” in a way that can reduce disease activity over time.

How Does Mavenclad Work?

To understand Mavenclad, imagine your immune system as an overexcited security team that can’t tell the difference between intruders and your own nervous system. In MS, certain white blood cellsespecially lymphocytesmistakenly attack the protective coating (myelin) around nerves in the brain and spinal cord.

Mavenclad contains cladribine, a medicine that selectively targets and reduces these overactive lymphocytes. By lowering their numbers for a period of time, Mavenclad can:

• Decrease the frequency of MS relapses
• Slow the build-up of disability
• Reduce new inflammatory lesions on MRI scans

The key idea: it’s not a daily permanent shutdown of your immune system. It’s a short, intensive course aimed at “resetting” immune activity related to MS. Your immune system gradually recovers, but the treatment effect can persist beyond the actual dosing days.

Who Is Mavenclad For?

Mavenclad is approved for adults with relapsing forms of MS, including:

• Relapsing-remitting multiple sclerosis (RRMS)
• Active secondary progressive multiple sclerosis (active SPMS)

Because of its safety profile and serious warnings, Mavenclad is usually considered for people who:

• Have tried at least one other MS disease-modifying therapy without enough benefit, or
• Couldn’t tolerate another MS treatment due to side effects or other issues

Mavenclad is not recommended for people with clinically isolated syndrome (CIS), and it is contraindicated in certain situations, which we’ll get into below.

Important Boxed Warnings and Safety Concerns

Mavenclad comes with serious warnings. This is not a “lightweight” medication, even if the dosing schedule looks convenient. Two major issues are front and center:

1. Risk of Malignancy (Cancer)

Mavenclad may increase the risk of certain cancers. Because of this:

• It is contraindicated in people with an active malignancy.
• People with a history or increased risk of cancer need a careful, individualized risk–benefit discussion with their healthcare team.
• Regular cancer screening as recommended for age and sex (for example, skin checks, mammograms, colon cancer screening) is especially important while using Mavenclad and afterward.

2. Risk of Teratogenicity (Harm to an Unborn Baby)

Mavenclad can cause serious harm to a developing fetus. Because of this:

• It is contraindicated during pregnancy.
• It is also contraindicated in women and men of reproductive potential who will not use effective contraception during dosing and for a period afterward (typically at least six months after the last dose of each treatment course, per prescribing information).
• Women should have a pregnancy test before starting each treatment course.

If pregnancy occurs during treatment or within the recommended post-treatment window, immediate contact with a healthcare provider is essential.

Other Key Warnings

In addition to cancer and pregnancy risks, Mavenclad carries several other important warnings:

• Serious infections: Because Mavenclad lowers certain immune cells, it can increase the risk of infections, including shingles, other viral infections, and potentially serious or opportunistic infections. People should be screened for certain infections (for example, tuberculosis and hepatitis) before treatment, and vaccination history is reviewed.
• Progressive multifocal leukoencephalopathy (PML): PML is a rare but serious brain infection that has been associated with profound immune suppression. Anyone developing new neurologic symptoms (such as vision changes, weakness, confusion, or difficulty speaking) needs urgent evaluation.
• Liver problems: Mavenclad can affect liver function, so blood tests are usually done before and during treatment to monitor liver enzymes.
• Low blood counts: Lymphocyte counts (and sometimes other blood cells) can drop significantly, which is part of how the drug works, but must be monitored closely.

Common and Serious Side Effects of Mavenclad

Side effects don’t show up the same way in every person, but some patterns are well known. Common side effects reported with Mavenclad include:

• Upper respiratory infections (such as colds or sinus infections)
• Headache
• Low white blood cell counts, especially low lymphocytes
• Herpes zoster (shingles) or other herpes infections
• Rash or skin changes
• Nausea or mild stomach upset

More serious side effects, while less common, are the ones your healthcare team watches for closely:

• Severe infections or infections that don’t improve as expected
• Signs of liver damage (yellowing of the skin or eyes, dark urine, abdominal pain, severe fatigue)
• Allergic or hypersensitivity reactions (swelling, difficulty breathing, severe rash)
• Potential malignancies over time

Because Mavenclad changes immune cell levels, many side effects tie directly back to immune system suppression. Regular blood work is not just “busywork”it’s how clinicians track whether lymphocyte counts are at safe levels and whether the body is tolerating therapy.

How Mavenclad Is Taken: Dosing Overview

One of the biggest selling points of Mavenclad for many people is its short-course dosing schedule. Instead of taking a pill every day forever, Mavenclad is usually taken only on a limited number of days over two years.

Here’s the high-level structure (always follow your neurologist’s instructions and the official prescribing information):

• Total treatment period: Typically two treatment courses, one in Year 1 and one in Year 2.
• Weight-based dosing: The total dose is calculated according to body weight. Your healthcare team will determine exactly how many 10-mg tablets you need.
• Two cycles each year: Each yearly course is split into two short “cycles.” Each cycle lasts 4 or 5 days. Within each cycle, you usually take 1 or 2 tablets per day.
• Gap between cycles: The two cycles in a given year are separated by about a month.
• Years 3 and 4: Many people do not receive additional Mavenclad during these years, although monitoring continues.

Mavenclad tablets are taken by mouth, swallowed whole with water, and usually taken on an empty stomach or as instructed by your provider. Tablets should not be crushed or chewed. Because the medication can be harmful if handled incorrectly (particularly for pregnant people), you’ll get specific instructions for storage and handling.

Monitoring Before, During, and After Treatment

Because Mavenclad is powerful, screening and monitoring routines are built into the treatment plan. These may include:

• Blood tests to check blood counts (especially lymphocytes), liver function, and sometimes kidney function.
• Infection screening (for example, hepatitis, tuberculosis, and prior exposure to certain viruses).
• Vaccination review: Certain vaccines may need to be given before Mavenclad, particularly live vaccines, which generally should not be administered during or soon after treatment.
• Pregnancy testing for women of childbearing potential before each treatment course.
• Ongoing follow-up visits to monitor for new symptoms, side effects, or MRI changes.

This might sound like a lot of labs and check-ins, but for many people it is still less time-consuming than regular infusion days or self-injections every week for years on end.

Drug Interactions: What to Watch For

Mavenclad’s interaction profile is mainly centered around its impact on the immune system and how it’s handled in the body. Some key categories that your provider will consider include:

• Other immunosuppressive or immunomodulating drugs: Using Mavenclad together with other strong immune-suppressing medications can raise the risk of serious infections. Your neurologist will usually avoid overlapping potent therapies and may space them apart in time.
• Live vaccines: Because of increased infection risk, live or live-attenuated vaccines are generally avoided during and shortly after Mavenclad treatment. Inactivated vaccines may be given, but timing may be adjusted for best effectiveness.
• Drugs that affect kidney function: Since cladribine is partly cleared via the kidneys, medications that significantly reduce kidney function may require extra caution and monitoring.
• Certain antiviral medications or other treatments that affect cell transporters: Your provider and pharmacist will review your full medication list, including over-the-counter drugs and supplements.

Never start or stop medications, including herbal products, without letting your healthcare team know. A “simple” supplement or new prescription from another doctor can sometimes change the risk profile when combined with Mavenclad.

Pictures: What Does Mavenclad Look Like?

Mavenclad comes as small, white, round tablets, each containing 10 mg of cladribine. The tablets typically have identifying markings (such as a “C” and “10”) so pharmacists and patients can distinguish them from other medications. They are supplied in specialized packaging designed to reduce the risk of accidental exposure, especially for children or pregnant people in the household.

Your pharmacy will provide the exact product approved for use in your country, but if a tablet ever looks different from what you expect, ask your pharmacist before taking it.

Who Should Not Take Mavenclad?

Mavenclad is not appropriate for everyone. In general, it is contraindicated in people who:

• Have a current malignancy (active cancer)
• Are pregnant, or planning pregnancy in the immediate future
• Are breastfeeding (cladribine can pass into breast milk; breastfeeding usually must be stopped during and for a period after treatment)
• Have HIV infection or other conditions associated with significant immune suppression
• Have active chronic infections that have not been adequately treated

There may be additional reasons why Mavenclad is not recommended, including certain liver or kidney problems, very low baseline lymphocyte counts, or other medical issues. Only a clinician familiar with your full health history and current medications can determine whether Mavenclad is an appropriate option.

Living With MS on Mavenclad: What to Expect

People often describe Mavenclad treatment as “intense but brief.” Instead of building your week around injections or infusion center visits, you might find yourself focusing mainly on:

• A few short stretches of “pill days” in Year 1 and Year 2
• Regular blood draws and follow-up appointments
• Watching for signs of infection and staying up to date on recommended screenings

In clinical trials and real-world data, cladribine tablets have been shown to reduce relapse rates and MRI activity in many people with relapsing MS. That said, no MS therapy works perfectly for everyone. Some people experience substantial improvement in relapse control and quality of life; others may have only modest benefit or may switch therapies due to side effects or changing disease activity.

As with any MS treatment, success is measured not only in lab results and MRI scans, but also in how well you can continue your daily lifework, family, hobbies, and the goals that matter most to you.

Real-World Experiences With Mavenclad: What Patients Often Share

Every person’s story with MS is unique, but certain themes commonly show up when people talk about their experiences on Mavenclad. The following examples are composites based on reported experiences and are not quotes from specific individuals.

1. Appreciating the Low-Frequency Dosing

Many people say the biggest shift is mental. One woman who had previously spent full days at the infusion center described Mavenclad as “strange in a good way”she had a handful of intense treatment days, then months where MS treatment wasn’t the center of her calendar. Instead of juggling work, childcare, and infusion appointments, she mainly had lab visits and routine follow-ups. That sense of “not being constantly in treatment” helped her feel less defined by her diagnosis.

2. Managing Fatigue and Side Effects During Treatment Weeks

Others talk about planning ahead for treatment cycles. One man scheduled his dosing weeks when his workload was lighter. He noticed mild headaches and more fatigue on pill days, so he arranged for simpler meals, fewer social commitments, and a bit more rest. His partner helped keep track of the dosing schedule and reminded him to drink fluids and report anything unusual to his care team. By treating those weeks like a “mini project,” they felt more in control and less overwhelmed.

3. Coping With Infection Risk and Lifestyle Adjustments

Because Mavenclad lowers certain immune cells, infection prevention becomes a bigger part of day-to-day life. People often describe getting more conscious about handwashing, staying away from obviously sick contacts during the most immunosuppressed period, and keeping current on recommended vaccines as arranged with their provider.

For one teacher, this meant temporarily wearing a mask more often during cold and flu season and being more strict about using sick days when necessary. While that wasn’t always convenient, she felt it was a reasonable tradeoff for fewer relapses and less disability progression.

4. Emotional Ups and Downs

Starting Mavenclad can bring mixed emotionshope for better disease control, anxiety about serious side effects, and sometimes grief about needing a high-risk medication at all. People often find it helpful to:

• Ask detailed questions during neurology visits so they understand the plan
• Bring a family member or friend to appointments for support
• Connect with MS support groups (in person or online) where others share their experiences with different treatments, including Mavenclad
• Work with a therapist familiar with chronic illness to process the emotional side of treatment decisions

5. Long-Term Perspective: Balancing Risks and Benefits

Because Mavenclad comes with warnings about cancer and serious infections, many people describe the decision as a weighing of long-term risks. On one side: the possibility of more disability, more relapses, and more MRI lesions if MS is not well-controlled. On the other side: the potential for malignancy, infection, and other side effects associated with a potent immune-modifying therapy.

Some patients say they felt more comfortable after reviewing the official prescribing information with their neurologist, looking at their personal risk factors, and comparing Mavenclad with other options. Others decided it wasn’t the right fit and chose a different disease-modifying therapy. Neither choice is “wrong”what matters is that the decision is informed, intentional, and tailored to the individual.

In the end, Mavenclad can be a powerful tool for some adults with relapsing MS, but it is not a casual choice. Partnering closely with a knowledgeable MS specialist, keeping all recommended monitoring appointments, and speaking up about side effects or new symptoms are crucial parts of using this medication as safely and effectively as possible.

Bottom Line

Mavenclad (cladribine) is a short-course oral medication for certain relapsing forms of multiple sclerosis. It offers a convenient dosing schedule and proven effects on relapse rates and MRI activity, but it also carries serious risks, including potential malignancies, fetal harm, and serious infections. It’s typically reserved for adults who have not responded adequately to other MS treatments or cannot tolerate them.

If you’re considering Mavenclad, think of it as one powerful option in a larger MS toolkitnot the right answer for everyone, but a valuable choice for some. The decision should always be made in close collaboration with a neurologist who knows your medical history, life plans, and treatment goals.