Could Antiviral Drugs Help Control Alzheimer Disease?

Neuroscientists are starting to recognize that the brain is not a sterile organ. In other words, the brain has a microbiome just like the digestive tract. There are bacteria, fungi and viruses that populate our brain and central nervous system (CNS). For years, some researchers have suggested that viruses might be associated with dementia and other neurodegenerative conditions. Is there any way antiviral drugs might help control Alzheimer disease?

According to the Alzheimer’s Association, over 7 million Americans now have Alzheimer disease (AD). Over the next 25 years, this form of dementia is expected to double. There are currently no medications that prevent AD and the drugs that have been approved in recent years barely slow the decline. If we don’t come up with some effective treatments soon, dementia will overwhelm our medical system.

Could AIDS Drugs Help Delay AD?

A new study published in the journal Alzheimer’s & Dementia (May 8, 2025) reports a novel use for certain HIV drugs against AD. Researchers analyzed medical records from the Veterans Administration and a private insurance company for as long as 24 years. A total of 270,000 individuals participated in the study.

People taking a special kind of HIV drug called nucleoside reverse transcriptase inhibitors  were less likely to be diagnosed with Alzheimer disease. People taking other types of HIV medications were not protected.

The annual reduction in Alzheimer disease cases ranged from  6% to 13%. That is impressive. The senior author of the study speculates that such drugs:

“could prevent approximately 1 million new cases of Alzheimer’s disease every year.”

Before such drugs could be employed against AD, however, the FDA is likely to require randomized controlled trials. Scientists will also want to better understand the mechanism of action of these drugs.

The authors of the recent research describe “inflammasome activation” as a critical step in the development of AD. Inflammasomes are complex proteins that play a crucial role in the immune system. When activated, they help fight viral, bacterial and fungal infections.

The nucleoside reverse transcriptase inhibitors (NRTIs) inhibit inflammasome activation. Such drugs include the brands Baraclude, Epivir, Emtriva, Retrovir, Viread, Vemlidy, Ziagen and Hepsera.

The investigators conclude:

“A therapy that inhibits inflammasome activation could thus be neuroprotective and improve clinical outcomes in AD. In the present study, we demonstrate that exposure to inflammasome‐inhibiting NRTIs is associated with a significantly lower incidence of AD in two of the largest health insurance databases in the United States.”

Would Drugs to Combat Herpes Also Help Control Alzheimer Disease?

One reader asked this questions:

Q. I have read on your website that herpes infections have been linked to Alzheimer disease. If there is a connection, would taking an antiviral medicine (one that combats both cold sores and genital herpes) be helpful?

A. You are asking a brilliant question. Scientists have been proposing that Alzheimer disease may be linked to herpes infections (Neuron, June 21, 2018).

Here, in the authors’ words, is their overview:

“Investigators have long suspected that pathogenic microbes might contribute to the onset and progression of Alzheimer’s disease (AD) although definitive evidence has not been presented. Whether such findings represent a causal contribution, or reflect opportunistic passengers of neurodegeneration, is also difficult to resolve…

“We observed increased human herpesvirus 6A (HHV-6A) and human herpesvirus 7 (HHV-7) from subjects with AD compared with controls. These results were replicated in two additional, independent and geographically dispersed cohorts.”

How Could Antiviral Drugs Help Control Alzheimer’s Disease?

The peptide that makes up amyloid plaques typical of Alzheimer disease appears to be the brain’s way of fighting infection. Learn more about this in our free one-hour radio interview with Dr. Robert Moir and Dr. Dale Bredesen. It is Show 1132 available online at www.PeoplesPharmacy.com.

Some physicians suggest that antiviral medicines should be tested as a way of treating Alzheimer disease (Frontiers in Aging Neuroscience, March 6, 2018).

“This review focuses on research in the areas of epidemiology, neuropathology, molecular biology and genetics that implicates herpes simplex virus type 1 (HSV-1) as a causative agent in the pathogenesis of sporadic Alzheimer’s disease (AD)…

“Studies are reviewed supporting subclinical chronic reactivation of latent HSV-1 in the brain as significant in the pathogenesis of AD. Finally, the rationale for and importance of clinical trials treating HSV-1-infected MCI [mild cognitive impairment] and AD patients with antiviral medication is discussed…

“By halting the direct and indirect toxic effects of HSV-1 on neuronal cells, antiviral medication may play a role in the prevention and treatment of AD.”

Can Valacyclovir Help Control Alzheimer Disease?

In fact, two clinical trials are recruiting study subjects to test the antiviral drug valacyclovir against AD. One is at the New York State Psychiatric Institute and the other is at University Hospital in Umea, Sweden. Learn more at ClinicalTrials.gov

In The Meantime?

It will likely be years before we know if anti-HIV drugs and anti-herpes drugs like valacyclovir do anything to help control Alzheimer disease. We are glad such research is now under way. In the meantime, we received an intriguing message from someone who read our newspaper column on this topic:

Karen in California writes:

“In reading your article about antiviral medication and Alzheimer’s – I would like to add another suggestion. I just retired as an engineer. I am a woman of a certain age. I feel mentally alert and grateful because dementia runs in the female side of our family and my only sibling is showing signs.

“When I was 35, I had an extreme bout of herpes that lasted 2 months and affected a quarter of my lips. I researched and found L-lysine as something that could combat the extensive lip flare-up. My herpes infection finally started abating.

“I decided to make L-lysine a regular part of my vitamin regiment and for 35 years have taken 500 mg daily. When the occasional (yearly or so) signs of a cold sore start to show, I up my dose. Perhaps rather than an antiviral med, L-lysine could play a role that may also help control Alzheimer’s disease as a spin off benefit.”

Share your own thoughts on this intriguing relationship between herpes viruses and Alzheimer disease in the comment section below.