FDA approval controversy

There has been considerable controversy surrounding Aduhelm since the Food and Drug Administration (FDA) granted the drug accelerated approval in 2021.

The accelerated approval of Aduhelm has been controversial for several reasons, and the issue is ongoing. For more information, see the “Aduhelm approval controversy” section below.

Aduhelm is a brand-name drug that’s prescribed for Alzheimer’s disease. Aduhelm contains the active drug aducanumab-avwa and is a type of monoclonal antibody.

Aduhelm is FDA-approved for adults with early stages of Alzheimer’s disease who have mild cognitive impairment or mild dementia (trouble with memory, learning, concentrating, or decision making).

Drug details

Aduhelm contains the active drug aducanumab-avwa.* It’s a type of biologic drug called a monoclonal antibody. Biologic drugs are made using living cells, and monoclonal antibodies are drugs that target particular proteins. Aduhelm targets beta-amyloid (a type of protein) in the brain.

The cause of Alzheimer’s disease isn’t fully understood. But in the brains of people with this disease, beta-amyloid protein buildup occurs. This protein forms deposits called plaques that block communication between the nerve cells in the brain. Aduhelm helps the immune system break down these plaques.

Aduhelm comes as a liquid solution inside single-dose vials. A healthcare professional will give you this medication by intravenous (IV) infusion once every 4 weeks.

Note: As a person’s condition progresses, they may need help reading or understanding information regarding their circumstances. This article contains details that may help caregivers identify and monitor symptom progression, side effects of drugs, or other factors relating to the person’s condition.

* The reason “-avwa” appears at the end of Aduhelm’s name is to show that the drug is distinct from similar medications that may be created in the future.

FDA approval

The Food and Drug Administration (FDA) approved Aduhelm for Alzheimer’s disease in 2021. This is the first treatment approved for Alzheimer’s disease that targets beta-amyloid plaques in the brain.

It’s important to note that the drug received accelerated approval from the FDA.

The FDA gives accelerated approval to certain drugs if early clinical trials suggest that they may be effective for treating a certain condition. More extensive clinical trials must then be done to confirm whether the drug provides actual benefit for people with that condition. Based on the results of these studies, the FDA may decide to fully approve the drug or withdraw the approval.

The accelerated approval process can speed up access to potentially effective new drugs for conditions that don’t have many treatment options. Alzheimer’s disease is an example of such a condition.

Early studies of Aduhelm show that it reduces beta-amyloid plaques in the brains of people with mild Alzheimer’s disease. However, the studies don’t clearly show whether Aduhelm reduces Alzheimer’s symptoms or slows the progression (worsening) of the disease. Because of this, the approval of Aduhelm has been controversial. To read more about this, see the “Aduhelm approval controversy” section below.

Aduhelm is a biologic drug that’s only available as a brand-name medication. It’s not currently available in generic or biosimilar form.

A biologic drug is made using living cells, whereas traditional drugs are made using chemicals. Exact copies of the active ingredient in brand-name chemical drugs can be made. These are called generics. Generics are just as safe and effective as the original drug, but they usually cost less than the brand-name version.

It’s not possible to make exact copies of biologic drugs. Instead, similar versions of brand-name biologic drugs can sometimes be made. These are called biosimilars. Like generics, biosimilars are considered just as safe and effective as the parent drug that they’re based on. And like generics, they usually cost less than the brand-name parent drug.

As with all medications, the cost of Aduhelm can vary.*

The actual price you’ll pay depends on your insurance plan, your location, and the pharmacy you use.

Before approving coverage for Aduhelm, your insurance company may require you to get prior authorization. This means that your doctor and insurance company will need to communicate about your prescription before the insurance company will cover the drug. The insurance company will review the prior authorization request and decide whether the drug will be covered.

If you’re not sure whether you’ll need prior authorization for Aduhelm, contact your insurance company.

To learn more about Aduhelm and cost, see this article.

* Even with varying prices, the cost of Aduhelm will typically be high. This has raised public concern. For more information, see “The high cost of Aduhelm makes the drug less accessible” in the “Aduhelm approval controversy” section below.

Financial and insurance assistance

If you need financial support to pay for Aduhelm or if you need help understanding your insurance coverage, help is available.

Biogen, the manufacturer of Aduhelm, offers a program called Biogen Support Services for Patients. Through this program, you may find financial assistance for Aduhelm. For more information and to find out whether you’re eligible for support, call 833-425-9360 or visit the drug’s website.

To learn more about saving money on prescriptions, refer to this article.

Generic or biosimilar version

Aduhelm is a biologic drug that’s not currently available in generic or biosimilar form. For more information, see the “Aduhelm generic or biosimilar” section above.

Aduhelm can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while using Aduhelm. These lists do not include all possible side effects.

For more information about the possible side effects of Aduhelm, talk with your doctor or pharmacist. They can give you tips on how to address any side effects that may be concerning or bothersome.

Note: The Food and Drug Administration (FDA) tracks side effects of drugs it has approved. If you would like to notify the FDA about a side effect you’ve had with Aduhelm, you can do so through MedWatch.

Mild side effects

Mild side effects* of Aduhelm can include:

Most of these side effects may go away within a few days or a couple of weeks. But if they become more severe or don’t go away, talk with your doctor or pharmacist.

* This is a partial list of mild side effects Aduhelm can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or view Aduhelm’s prescribing information.
† For more information about this side effect, see “Side effect details” below.

Serious side effects

Serious side effects of Aduhelm can occur. Call your doctor right away if you have serious side effects. Call 911 or your local emergency number if your symptoms feel life threatening or if you think you’re having a medical emergency.

Serious side effects can include:

* For more information about this side effect, see “Side effect details” below.
Aduhelm has a boxed warning for this side effect. This is the most serious warning from the FDA. To learn more, see “Side effect details” below.

Side effect details

Here’s some detail about certain side effects that this drug may cause.

Amyloid-related imaging abnormalities (ARIA)

Aduhelm has a boxed warning about amyloid-related imaging abnormalities (ARIA). A boxed warning is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous.

Aduhelm can cause ARIA. While these changes don’t result in any symptoms in most people, they may show up on brain MRI scans. And they can be a sign of temporary swelling or small spots of bleeding in areas of the brain. Such side effects may be life threatening or even fatal in rare cases.

In clinical trials, temporary swelling in areas of the brain was the most common side effect reported with Aduhelm. People who have swelling in the brain with Aduhelm may also have small spots of bleeding in the brain. Bleeding in the brain occurred less often than swelling. But it was still common in clinical trials of Aduhelm.

It’s not fully understood what causes these side effects. But they’re related to the breakdown of beta-amyloid deposits, called plaques, in the brain, which is how Aduhelm works.*

* For more information, see the “How Aduhelm works” section below.

Increased risk of ARIA in people with a certain APOE genotype

ARIA may occur more often in people with a certain genotype (version) of the apolipoprotein E (APOE) gene if they receive Aduhelm. The specific genotype of this gene is called ε4 homozygous.

Before a person starts Aduhelm treatment, their doctors may give them a test to determine whether they have this APOE genotype.

Symptoms to watch for

Most cases of swelling or bleeding in the brain are mild or moderate. But sometimes these side effects can be serious. And in some people they can cause symptoms, such as:

Most cases of swelling or bleeding in the brain occurred early in treatment. However, these side effects can happen at any time while using Aduhelm. And some people may have more than one episode.

What to do

If you have symptoms of swelling or bleeding in your brain while receiving Aduhelm, tell your doctor right away. Caregivers of people receiving Aduhelm should also watch for these symptoms and report them immediately. People with these symptoms may need an MRI scan of the brain to check for areas of swelling or bleeding.

You’ll have a brain MRI scan before you start treatment with Aduhelm. You’ll also need a brain MRI scan before your fifth, seventh, ninth, and 12th doses of Aduhelm. These scans will check for any swelling or bleeding in your brain that may occur without causing symptoms.

If you have the ε4 homozygous genotype of the APOE gene, your doctor may monitor you more often for ARIA during treatment.

If you have swelling or small spots of bleeding in your brain, this typically gets better over a few weeks. If the swelling or bleeding is moderate or severe, your doctor may decide to temporarily stop your treatment with Aduhelm until the swelling eases. But if you have severe bleeding, you may need to permanently stop receiving Aduhelm.

Headaches

Aduhelm can cause headaches. In clinical trials, headaches were among the more common side effects reported with Aduhelm.

Note that headaches might sometimes be a symptom of swelling or small spots of bleeding in your brain. These are common side effects of Aduhelm that can sometimes be serious. To read more about this, see the “Amyloid-related imaging abnormalities (ARIA)” section just above.

What to do

If you have headaches while receiving Aduhelm, talk with your doctor right away. They can recommend ways to ease this side effect.

Allergic reaction

As with most drugs, some people can have an allergic reaction after using Aduhelm.

Symptoms of a mild allergic reaction can include:

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include:

  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your tongue, mouth, or throat
  • difficulty breathing

Call your doctor right away if you have an allergic reaction to Aduhelm, as the reaction could become severe. Call 911 or your local emergency number if your symptoms feel life threatening or if you think you’re having a medical emergency.

The dosage of Aduhelm is based on your body weight.

Typically, your doctor will start you on a low dosage of Aduhelm. Then they’ll increase it over time until the recommended dosage is reached. The following information describes dosages that are commonly used or recommended.

Drug forms and strengths

Aduhelm comes as a liquid solution inside single-dose vials. A healthcare professional will prepare the medication to give to you by intravenous (IV) infusion. An IV infusion of Aduhelm takes about 1 hour.

Aduhelm vials come in two sizes:

  • 170 milligrams (mg)/1.7 milliliters (mL)
  • 300 mg/3 mL

Dosage for Alzheimer’s disease

You’ll receive an Aduhelm IV infusion once every 4 weeks. Your doctor or another healthcare professional will likely increase your dosage gradually as follows:

  • Infusions one and two: 1 mg per kilogram (mg/kg)* of body weight
  • Infusions three and four: 3 mg/kg of body weight
  • Infusions five and six: 6 mg/kg of body weight
  • Infusions seven and so on: 10 mg/kg of body weight

* One kg is equal to about 2.2 pounds.

What if I miss a dose?

If you miss an appointment to have an infusion of Aduhelm, call your doctor’s office right away to reschedule. You should have the missed dose as soon as possible. Note that the manufacturer recommends that doses be given at least 21 days apart.

To help make sure that you don’t miss a dose, try using a medication reminder. This can include setting an alarm or timer on your phone or downloading a reminder app.

Will I need to use this drug long term?

Aduhelm is meant to be used as a long-term treatment. If you and your doctor determine that Aduhelm is safe and effective for you, you’ll likely use it long term.

The Food and Drug Administration (FDA) approves prescription drugs such as Aduhelm to treat certain conditions.

Aduhelm for Alzheimer’s disease

Aduhelm is FDA-approved to treat Alzheimer’s disease. Specifically, it’s approved for use in people with early stages of the disease who have mild cognitive impairment or mild dementia. For this purpose, the FDA granted Aduhelm accelerated approval. For more information, see “FDA approval” above.

About Alzheimer’s disease

A person with mild cognitive impairment has trouble with memory, learning, concentrating, or decision making. But they’re still able to function on their own. A person with mild dementia has cognitive impairment that makes it difficult to function on their own.

Alzheimer’s disease is the most common cause of dementia. It’s a long-term disease that gets worse over time.

Symptoms of mild Alzheimer’s disease can include:

  • memory loss
  • repeating questions
  • difficulty with planning and solving problems
  • difficulty working with numbers and handling money or bills
  • difficulty completing familiar tasks
  • losing track of dates and time
  • difficulty with conversation and finding words
  • misplacing things and being unable to retrace steps
  • changes in mood and personality, such as becoming anxious, suspicious, confused, or depressed

The cause of Alzheimer’s and what Aduhelm does

The cause of Alzheimer’s disease isn’t fully understood. But two main features develop in the brains of people with the disease:

  • Deposits of a protein called beta-amyloid develop between nerve cells. These deposits, referred to as plaques, block communication between the nerve cells.
  • Tangles of a protein called tau develop inside nerve cells. The tangles block the transport system inside these cells. This stops nerve cells from communicating correctly and disrupts processes that they need to survive.

These changes cause nerve cells in the brain to die and brain tissue to shrink over time.

Aduhelm targets the beta-amyloid plaques in your brain. It helps your immune system break down these plaques. It’s thought that breaking down the plaques may improve nerve cell communication. But it’s not known for sure whether this will happen. For more information, see the “How Aduhelm works” section below.

Effectiveness for Alzheimer’s disease

Clinical trials show that Aduhelm reduces beta-amyloid plaques in the brains of people with Alzheimer’s disease who have mild cognitive impairment or mild dementia.

But it’s not clear whether the drug slows the progression (worsening) of Alzheimer’s. It’s also not clear whether it reduces symptoms of the disease.

In one trial, people who received Aduhelm had less worsening of their Alzheimer’s than people who received a placebo (treatment containing no active drug). But in a second trial, people who received Aduhelm had worsening of Alzheimer’s that was similar to people who received a placebo. Researchers hope that other ongoing studies will answer questions about the drug’s effectiveness.

Aduhelm hasn’t been studied in people with earlier* or later stages of Alzheimer’s disease.

For more information about how this medication performed in clinical trials, see the drug’s prescribing information.

* Changes in the brain caused by Alzheimer’s can occur years before disease symptoms develop. This stage is called preclinical Alzheimer’s disease.

Aduhelm and children

Aduhelm is not approved for use in children. The drug hasn’t been studied in children, since Alzheimer’s disease doesn’t affect children.

There has been considerable controversy over the approval of Aduhelm. This is the first drug approved for Alzheimer’s disease that targets one of the changes in the brain that occurs with the disease.

The Food and Drug Administration (FDA) granted accelerated approval for Aduhelm in 2021.

A drug may receive accelerated approval if early clinical trials suggest that it could be effective for certain conditions. Specifically, the FDA reserves this type of approval for conditions that don’t have many effective treatment options, such as Alzheimer’s disease. Based on results from more extensive studies, the FDA may decide to fully approve the drug or withdraw the approval.

The accelerated approval of Aduhelm was controversial for several reasons.

It’s not known for sure whether Aduhelm has benefit for people receiving it

Early studies showed that Aduhelm significantly reduced beta-amyloid deposits called plaques in the brains of people with mild Alzheimer’s disease. These plaques, a key feature of the disease, are involved in causing nerve cells in the brain to die. But it’s not known whether reducing the plaques will lead to decreased symptoms or slowed disease progression (worsening).

The two main studies of Aduhelm had different outcomes, in this respect. One found that Aduhelm slowed the progression of the disease in people using the drug compared with people who took a placebo (treatment containing no active drug).

But in the second study, people who received Aduhelm had disease progression (worsening of symptoms) similar to people who received a placebo.

The FDA expects that reducing amyloid plaques is likely to slow the progression of Alzheimer’s disease. But there is disagreement among experts over this. This is partly because other drugs that work this way, such as solanezumab and bapineuzumab, haven’t been found to produce significant benefits.

Until more studies of Aduhelm are completed, it’s not known whether the drug is an effective treatment for Alzheimer’s disease.

Aduhelm was initially approved for all stages of Alzheimer’s

The FDA initially approved Aduhelm for people with all stages of Alzheimer’s disease. But the drug had only been studied in people with mild forms of the disease. It hasn’t been studied in people with more severe forms or earlier* forms of Alzheimer’s.

After much criticism, the FDA changed its approval shortly after its initial approval. Aduhelm is now only approved for people with milder forms of Alzheimer’s disease.

* Changes in the brain caused by Alzheimer’s can occur years before disease symptoms develop. This is called preclinical Alzheimer’s disease.

Criticism of the FDA leads to an investigation

Before Aduhelm was approved, an FDA expert advisory panel reviewed the data from early clinical trials of the drug. The panel advised that there wasn’t strong enough evidence of a benefit from Aduhelm to approve the drug.

But the FDA granted accelerated approval despite this advice. This, along with the initial approval of the drug for all stages of Alzheimer’s, led three panel members to resign.

The FDA called for an independent federal investigation into its representatives’ interactions with Biogen. Biogen is the manufacturer of Aduhelm. The investigation, which lasted 18 months, uncovered irregularities in the approval process for Aduhelm. The congressional report of the investigation included several recommendations for the FDA and drug manufacturers to improve their processes in the future.

The high cost of Aduhelm makes the drug less accessible

Patient support and advocacy groups have welcomed Aduhelm’s FDA approval. But the high cost of the drug is also causing a lot of concern.

Aduhelm’s high cost is partly due to its being a biologic drug (a drug made using living cells). Biologics have high research and production costs. But there are also extra costs involved with Aduhelm use. A person receiving Aduhelm needs brain MRI scans to monitor for side effects of the drug.

The high cost of Aduhelm treatment will make it inaccessible to many. And it may prevent insurance companies from funding it. This is especially so because the treatment will likely be long term, and it’s not yet known whether Aduhelm is effective.

Some large health systems, such as the Cleveland Clinic, have decided against carrying Aduhelm in their facilities for these reasons. And several insurance companies have already decided not to fund the treatment.

In April 2022, the Centers for Medicare and Medicaid Services announced that it will only provide coverage for the cost of Aduhelm for people receiving the medication through clinical trials. Medicare stated that this limited coverage is intended to help protect consumers until more is known about how Aduhelm works, its safety, and its effectiveness.

Approval could give false hope

Given all the controversy, there are concerns that Aduhelm’s approval could give false hope to people with Alzheimer’s and their families. And the results of further studies, which will confirm whether the drug is effective, aren’t expected until 2030.

If you’re interested in having this drug prescribed for yourself or a family member, you should discuss all pros and cons with your doctor.

Alcohol isn’t expected to interact with Aduhelm. However, drinking alcohol could increase certain side effects of Aduhelm, such as headaches. It could also increase the risk of falls.

If you drink alcohol, talk with your doctor about how much is safe to consume, if any, during treatment with Aduhelm.

Certain drugs can interact with other medications, herbs, supplements, and foods. Different interactions can cause different effects. For instance, some interactions can interfere with how well a drug works. Other interactions can make side effects more severe.

There aren’t any reported interactions between Aduhelm and other medications, herbs, supplements, or foods. But this doesn’t mean that interactions can’t happen with Aduhelm.

Before starting treatment with Aduhelm, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

A healthcare professional will give you Aduhelm by intravenous (IV) infusion. This is an injection into a vein that’s given over a period of time. The healthcare professional will administer the infusion in their clinic or office. Each infusion takes about 1 hour.

When it’s given

You’ll receive Aduhelm once every 4 weeks.

To help make sure that you don’t miss an appointment to have your infusion, try using a medication reminder. This can include setting an alarm or timer on your phone or downloading a reminder app.

Aduhelm is approved to treat Alzheimer’s disease. It’s used for people who have mild cognitive impairment or mild dementia due to early stages of the disease.

What happens with Alzheimer’s disease

With Alzheimer’s disease, a person gradually loses their ability to remember, think, reason, and solve problems. Symptoms are mild in the beginning but get worse over time, until severe dementia develops.

Scientists don’t fully understand the cause of Alzheimer’s disease. But they do know that certain changes happen in the brain with this disease. These changes stop the nerve cells in the brain from working correctly. Two key changes are as follows:

  • Deposits of a protein called beta-amyloid develop between nerve cells. These deposits, referred to as plaques, block communication between the nerve cells.
  • Tangles of a protein called tau develop inside nerve cells. The tangles block the transport system inside these cells. This stops nerve cells from communicating correctly and disrupts processes that they need to survive.

As a result of these changes, nerve cells in your brain gradually lose their ability to communicate. Over time, the nerve cells die, and your brain tissue shrinks.

What Aduhelm does

Aduhelm is a type of medication called a monoclonal antibody. Monoclonal antibodies act on specific proteins in the body. Aduhelm works by attaching to the beta-amyloid protein in the brain. It helps the immune system break down and remove beta-amyloid plaques.

In theory, reducing beta-amyloid plaques may slow down damage to the nerve cells. This may decrease the symptoms of Alzheimer’s disease. It may also reduce the worsening of this disease. But it’s not known for sure whether reducing beta-amyloid plaques will have these effects. Studies to find out whether Aduhelm has these benefits are ongoing.

How long does it take to work?

Aduhelm starts reducing the beta-amyloid plaques in your brain soon after your first infusion. But it’s not known whether you’ll notice the drug making these changes.

It’s not known whether Aduhelm is safe to receive during pregnancy. It hasn’t been studied in people who are pregnant.

If you’re pregnant or planning to become pregnant, talk with your doctor about the risks and possible benefits of receiving Aduhelm.

It’s not known whether Aduhelm is safe to receive during pregnancy. If you’re sexually active and you or your partner can become pregnant, talk with your doctor about your birth control needs while you’re receiving Aduhelm.

For more information about receiving Aduhelm during pregnancy, see the “Aduhelm and pregnancy” section above.

It’s not known whether Aduhelm passes into breast milk. It’s also not known whether it can affect a child who’s breastfed by someone receiving Aduhelm treatment.

If you’re breastfeeding or planning to breastfeed, talk with your doctor about the risks and possible benefits of receiving Aduhelm.

Here are answers to some frequently asked questions about Aduhelm.

Does Aduhelm cure Alzheimer’s disease?

No, that’s unlikely. There’s no known cure for Alzheimer’s disease. When nerve cells in your brain die, it’s not possible for them to regenerate (come back). And it’s not possible to reverse the loss of brain tissue that occurs with the disease.

By reducing the beta-amyloid plaques in your brain, Aduhelm may help decrease Alzheimer’s symptoms or slow the worsening of the disease. (Beta-amyloid plaques are a buildup of protein between nerve cells in your brain. This is one change that happens in the brain of someone with Alzheimer’s.) But it’s not known for sure whether Aduhelm has these effects.

Studies to find out whether Aduhelm produces noticeable benefits for people with Alzheimer’s disease are ongoing.

Why do I need to have MRIs of my brain before and during Aduhelm treatment?

Aduhelm can sometimes cause side effects called amyloid-related imaging abnormalities (ARIA). This refers to areas of swelling or small spots of bleeding in your brain. These problems are usually mild or moderate, but they can sometimes be serious. In fact, Aduhelm has a boxed warning about ARIA. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous. For more information, see the “Aduhelm side effects” section above.

These side effects don’t always cause symptoms, but ARIA can be detected with an MRI scan of your brain.

Before you start treatment with Aduhelm, you’ll need to have a brain MRI scan. This scan allows your doctor to check for any recent bleeding in your brain. If you’ve had bleeding in your brain in the last year, Aduhelm may not be suitable for you.

You’ll need to have MRI scans during treatment with Aduhelm, as well. This allows your doctor to monitor you for swelling or bleeding in your brain. You’ll have an MRI scan before your fifth, seventh, ninth, and 12th infusions. You may also need an MRI scan if you develop symptoms of swelling or bleeding in your brain.

For more information about ARIA and Aduhelm, talk with your doctor.

How long do Aduhelm infusions take?

Each infusion of Aduhelm takes about 1 hour. But your whole visit will likely take a bit longer. The infusion is given every 4 weeks. To read more about how Aduhelm is given, see the “Aduhelm dosage” section above.

This drug comes with several precautions.

FDA warning: Amyloid-related imaging abnormalities

This drug has a boxed warning. This is a serious warning from the Food and Drug Administration (FDA). A boxed warning alerts doctors and patients about drug effects that may be dangerous.

Amyloid-related imaging abnormalities (ARIA). Aduhelm can cause ARIA. These changes, which are visible on a brain MRI scan, can involve swelling or bleeding in the brain. These effects may be life threatening or even fatal in rare cases. ARIA may occur more often in people with a certain genotype (version) of a particular gene if they receive Aduhelm.

For more information on this warning, see the “Aduhelm side effects” section above.

Other precautions

Before you receive Aduhelm, talk with your doctor about your health history. Aduhelm may not be right for you if you have certain medical conditions or other factors affecting your health. These include:

  • Allergic reaction. Anyone who has had an allergic reaction to Aduhelm or any of its ingredients shouldn’t receive Aduhelm. If you’ve had an allergic reaction to this drug, ask your doctor what other medications are better options for you.
  • Recent bleeding in your brain. Aduhelm can sometimes cause small spots of bleeding in the brain. You’ll need an MRI scan of your brain before you start treatment. Your doctor will review the MRI scan to check for any evidence of recent bleeding in your brain. If you’ve had bleeding in your brain in the past year, Aduhelm may not be suitable for you.
  • Blood thinners. Aduhelm can sometimes cause small spots of bleeding in the brain. People who take blood thinners may have a higher risk of this side effect. If you’re taking a blood thinner, talk with your doctor about whether Aduhelm is right for you.
  • APOE gene ε4 homozygous genotype. People with ε4 homozygous genotype of the apolipoprotein E (APOE) gene may have a higher risk of developing ARIA during treatment. If you have this genotype of the APOE gene, your doctor may monitor you more often for ARIA during treatment.
  • Pregnancy. It’s not known whether Aduhelm is safe to receive during pregnancy. For more information, see the “Aduhelm and pregnancy” section above.
  • Breastfeeding. It’s not known whether Aduhelm is safe to receive while breastfeeding. For more information, see the “Aduhelm and breastfeeding” section above.

Note: For more information about the potential negative effects of Aduhelm, see the “Aduhelm side effects” section above.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.