By Brandon M. Macsata, HIV-positive advocate

Senators Chuck Grassley (R-IA) and Amy Klobuchar (D-MN) recently introduced a bill that would permit Americans to import pharmaceuticals from Canada. The two lawmakers believe their bill will reduce drug costs.

The bill would instead expose patients to potentially dangerous counterfeit drugs. Lawmakers would be wise to vote against it.

Americans currently have the safest pharmaceutical supply chain in the world. In large part, that's thanks to the Food and Drug Administration, which strictly supervises medicines. About 60 percent of our drugs are manufactured at high-tech, ultra-safe facilities in the United States. The remainder are made in foreign factories but shipped into the United States through trusted vendors.

Sens. Grassley and Klobuchar's bill would allow people to purchase drugs that didn't go through this tightly controlled supply chain. That's worrying. No matter its rigorous safety precautions at home, the FDA can't vouch for the safety of foreign-made and supervised drugs.

This is particularly concerning when it comes to drugs from Canadian pharmacies, which often resell drugs imported from countries with subpar safety standards. One FDA investigation found that 85 percent of packages imported to the United States from online Canadian pharmacies contained potentially counterfeit drugs.

One in 10 drugs from low and middle-income countries is fake or substandard, according to the World Health Organization. Some are laced with deadly ingredients, like boric acid and fentanyl.

I've experienced firsthand the dangers of foreign drug imports. I was diagnosed with HIV. That day I found out I was destined to undergo antiretroviral therapy for the rest of my life.

When my out-of-pocket costs hit $1,300 in my second month of treatment, I started looking for a cheaper option. I began ordering my medicine from an online pharmacy in Canada.

It never crossed my mind that I might have been taking counterfeit medicine, or that the medicines could be compromising my immune system. So when my doctor found out, she told me to stop immediately.

Government officials have long opposed importation policies for the same reason.

Former FBI Director Louis J. Freeh warns that importation would "open up the U.S. drug supply to adulterated and counterfeit drugs."

Four past FDA commissioners penned a letter to Congress explaining that importation would "harm patients" and "compromise" the United States' "carefully constructed system."

And former HHS Secretary Mike Leavitt echoed similar concerns, writing that it was "impossible… to certify that importation of medicines from unregulated sellers is safe."

For nearly two decades, officials have warned against the dangers of drug importation. Let's listen to the experts -- importation is not a risk worth taking.

Brandon M. Macsata, HIV-positive advocate, is a political grassroots and media strategy consultant.