Alzheimer’s infusion treatment—medications like aducanumab (Aduhelm) and lecanemab (Leqembi)—involves receiving therapeutic drugs through an IV line at regular intervals, typically every two to four weeks depending on the medication. Before starting, patients undergo cognitive testing and amyloid PET imaging to confirm amyloid accumulation in the brain. During the infusion itself, which typically lasts one to two hours, the medication flows directly into the bloodstream while medical staff monitor vital signs.
After each infusion, patients return home and are advised to watch for specific side effects, particularly amyloid-related imaging abnormalities (ARIA), which can cause swelling or microhemorrhages in the brain. The entire treatment journey—from initial screening through ongoing infusions—requires coordination with a neurologist, regular imaging follow-ups, and commitment to a predictable schedule. A patient might begin with baseline cognitive testing in their neurologist’s office, schedule an amyloid PET scan at a specialty imaging center, then start biweekly infusion appointments at a hospital or infusion clinic. The stakes are significant: these drugs can slow cognitive decline by 25 to 35 percent in early symptomatic Alzheimer’s, but they carry a small risk of brain imaging abnormalities that can sometimes cause symptoms like headaches, confusion, or vision changes.
Table of Contents
- What Testing and Preparation Are Required Before Starting Infusion Treatment?
- What Happens During the Infusion Appointment Itself?
- What Side Effects and Monitoring Occur After Infusions?
- How Should Caregivers Manage the Ongoing Treatment Schedule?
- What Are the Most Common Reasons Patients Stop or Pause Treatment?
- What Should Patients Know About Cost and Insurance Coverage?
- When Might Infusion Treatment Not Be Appropriate?
What Testing and Preparation Are Required Before Starting Infusion Treatment?
Before a patient receives their first infusion, a neurologist will order cognitive testing to establish a baseline. This typically includes the Montreal Cognitive Assessment (MoCA) or similar tools that measure memory, attention, language, and processing speed. The results provide the clearest picture of where the patient stands cognitively before treatment begins—crucial information for assessing whether the medication is actually slowing decline. In parallel, an amyloid PET scan is mandatory; it shows whether amyloid plaques are actually accumulating in the brain. A patient who scores low on cognitive tests but shows no amyloid on PET may have a different cause of cognitive decline (vascular disease, frontotemporal dementia, Lewy body disease) and would not benefit from amyloid-targeting drugs. Genetic screening for the APOE4 gene variant is often performed as well.
Patients with one APOE4 copy have moderately elevated Alzheimer’s risk; those with two copies have very high risk. The gene doesn’t predict treatment response with certainty, but it helps establish overall risk profile. A 58-year-old woman with early memory loss, one APOE4 copy, positive amyloid PET, and a mother who had Alzheimer’s is far more likely to be a strong candidate for infusion treatment than a 72-year-old with borderline cognitive decline and no family history. The neurologist will also review medications, liver and kidney function via blood tests, and imaging history to rule out prior strokes or brain bleeds that might increase ARIA risk. Patients on anticoagulants like warfarin require closer monitoring during treatment. Insurance approval can take weeks; some insurers require additional evidence of disease progression or demand that patients have already failed other treatments.
What Happens During the Infusion Appointment Itself?
On infusion day, the patient arrives at a medical facility—usually an oncology infusion center, hospital outpatient clinic, or specialized neurology practice with infusion capabilities. A nurse starts an IV line, typically in the arm, and connects it to a bag of the monoclonal antibody medication. The infusion itself is not painful, though some patients report feeling a cold sensation as the IV fluid enters their vein. Heart rate, blood pressure, and oxygen saturation are monitored continuously. The entire appointment typically takes three to four hours when you include check-in, the infusion itself (usually 60 to 90 minutes), and a 30-minute observation period afterward to watch for any immediate reactions. During the infusion, some patients experience mild side effects—a headache, slight fever, or mild chills—though most feel nothing at all. These reactions are generally treated with acetaminophen or ibuprofen and do not require stopping the infusion.
A significant limitation of infusion treatment is that it requires repeated clinic visits on a fixed schedule. For rural patients or those without reliable transportation, this can become a genuine barrier. One 71-year-old man in a rural Montana town received his first four infusions then stopped attending appointments because the nearest infusion center was 90 minutes away; his cognitive decline accelerated once the treatment interval was broken. After the infusion is complete, the patient can drive home if they feel well and did not receive sedation (most don’t). They are instructed to drink extra fluids and may experience fatigue that evening. The medication begins working immediately at the cellular level—binding to amyloid plaques—but cognitive or symptomatic effects are not noticed acutely. This is important to understand: patients should not expect to feel sharper or remember better after one infusion. The benefit is measured in slowing decline over months, not improving function acutely.
What Side Effects and Monitoring Occur After Infusions?
The most serious potential side effect is amyloid-related imaging abnormality (ARIA), which comes in two forms. ARIA-E (amyloid-related imaging abnormality with edema) involves swelling in brain tissue, often in the cortex or near prior PET hotspots. ARIA-H (ARIA with microhemorrhages) involves tiny bleeding spots in the brain. These are detected only on MRI; they don’t always cause symptoms, but when they do, patients may experience headache, confusion, vision changes, balance problems, or mood shifts. Asymptomatic ARIA (visible on MRI but causing no symptoms) occurs in 15 to 20 percent of treated patients; symptomatic ARIA occurs in roughly 3 to 5 percent. Patients are scheduled for follow-up MRI imaging—typically three to four months after the first infusion, then annually or biannually depending on risk factors.
A 64-year-old woman in an early lecanemab trial developed mild asymptomatic ARIA-H on her third infusion; her neurologist reduced the infusion interval from biweekly to monthly, and no symptoms emerged. Had the imaging not been done routinely, the microhemorrhages would have gone undetected. This illustrates why regular imaging is non-negotiable—it allows clinicians to catch ARIA before it becomes symptomatic and to adjust the treatment plan. Common but non-serious side effects include headache (10 to 15 percent of patients), upper respiratory infection (possibly slightly elevated during treatment), and temporary cognitive confusion or “brain fog” immediately after infusion (reported by roughly 5 percent). These typically resolve within 24 to 48 hours. A limitation of the current data is that long-term side effect profiles beyond three years are limited; most trials tracked patients for 18 months. The long-term safety of repeated amyloid clearance over five or ten years remains incompletely understood.
How Should Caregivers Manage the Ongoing Treatment Schedule?
Managing a biweekly or monthly infusion schedule requires coordination. The patient’s spouse, adult child, or paid caregiver typically needs to arrange time off work or manage household tasks during the appointment. A typical appointment takes three to four hours, and many patients feel fatigued afterward, so caregivers should plan to accompany them and drive them home. Insurance often requires pre-authorization for each infusion; some insurers demand that patients demonstrate cognitive decline between visits to justify continued treatment. Caregivers should keep a simple log: infusion dates, any side effects reported, cognitive changes noticed at home, and MRI results. This information becomes invaluable at the six-month or annual neurology follow-up.
One comparison worth noting: infusion treatment demands much more active engagement than oral medications like aricept or memantine, which patients take at home daily. A caregiver managing an Alzheimer’s patient on infusions is essentially committing to twice-monthly or monthly clinic visits indefinitely, plus MRI appointments, lab work, and neurology visits. Families sometimes underestimate this logistical burden. Caregivers should also communicate clearly with the medical team about early changes they observe. If the patient seems more confused, more apathetic, or reports new headaches after infusions start, this information should be documented and reported promptly. Sometimes early ARIA symptoms are subtle—a patient’s spouse notices the person is sleeping more, or asking the same question more frequently than before—and these changes warrant imaging follow-up.
What Are the Most Common Reasons Patients Stop or Pause Treatment?
ARIA side effects that become symptomatic are the most common medical reason for pausing or stopping infusions. A patient with new headaches, confusion, or balance problems after an infusion requires immediate MRI; if ARIA is confirmed, the neurologist may reduce the infusion interval, adjust the dose, or discontinue the medication entirely depending on severity. This is a significant tradeoff: the medication slows cognitive decline, but it can trigger imaging abnormalities that need active management. Logistical barriers are the second major reason. Patients who move, lose reliable transportation, or develop other medical conditions that make biweekly clinic visits infeasible sometimes stop.
Insurance denial or requirement for additional prior authorization paperwork can delay or derail treatment initiation. A 69-year-old woman was approved for lecanemab by her neurologist but her insurance required documentation that she had already tried and failed two other medications; the authorization process took three months, during which her cognitive decline continued. Emerging cognitive impairment can also become a barrier. Infusion treatment is designed for mild cognitive impairment or mild dementia stages; it is not effective for moderate or severe Alzheimer’s. As a patient’s dementia progresses, the drug may no longer provide benefit, and the medical team may recommend discontinuing treatment. This is not a failure of the treatment; it reflects the reality that amyloid-targeting drugs work earlier in disease when amyloid accumulation is driving pathology, not later when neurodegeneration from tau tangles and neuroinflammation dominates.
What Should Patients Know About Cost and Insurance Coverage?
Lecanemab (Leqembi) costs approximately $26,500 per year for the standard biweekly infusion schedule. Aducanumab (Aduhelm) is priced similarly. Most patients do not pay this out-of-pocket; Medicare covers it for eligible beneficiaries, and many private insurers cover it with prior authorization. However, patients may face copayments, coinsurance (typically 20 percent of the drug cost), or deductibles.
Some infusion centers charge separate facility fees—$500 to $1,500 per appointment—on top of the drug cost. For a Medicare beneficiary, the new drug benefit phase, which begins once annual out-of-pocket costs exceed a certain threshold, generally means the patient pays 5 percent of the drug cost after that point. A patient hitting the coverage gap early in the year could pay thousands in coinsurance during the gap, then shift to the 5 percent tier. Uninsured or underinsured patients sometimes qualify for manufacturer copay assistance programs that can reduce out-of-pocket costs to $0 or a small fixed copay. The key is to ask the infusion center’s financial counselor about these programs before starting treatment.
When Might Infusion Treatment Not Be Appropriate?
Infusion treatment is not recommended for patients with moderate or severe dementia, because amyloid-targeted monoclonal antibodies are effective primarily when amyloid is actively accumulating in early disease. A patient with an MMSE score below 20 (indicating moderate cognitive impairment) is unlikely to benefit from amyloid clearance. Similarly, patients with a history of multiple strokes, severe cerebrovascular disease, or prior microbleeds are at higher risk of ARIA and are typically not candidates.
Patients unable or unwilling to commit to regular clinic visits and MRI monitoring should not start treatment. The drug’s efficacy is modest—slowing decline by 25 to 35 percent, not stopping it or reversing it—and that modest benefit only materializes with consistent adherence to the infusion schedule and imaging protocol. A patient who receives two or three infusions then stops will derive minimal benefit from the treatment.
