The world's first injectable medication to reduce the risk of acquiring HIV has been approved by the Food and Drug Administration (FDA), the agency announced Monday (December 20).

The injectable drug – called Apretude or its generic name, "cabotegravir extended-release injectable suspension" – provides an alternative to daily pills for HIV prevention, such as Truvada and Descovy. These pills are up to 99 percent effective at preventing the sexual transmission of HIV, but must be taken every day to be that effective, according to the Centers for Disease Control and Prevention (CDC).

By contrast, to start Apretude, people initially receive two shots, spaced one month apart, and then they receive an injection every two months thereafter, according to the FDA statement.

Related: 12 amazing images in medicine

"This injection, given every two months, will be critical to addressing the HIV epidemic in the US, including helping high-risk individuals and certain groups where adherence to daily medication has been a major challenge or not a realistic option," Dr. Debra Birnkrant, director of the Division of Antivirals in the FDA's Center for Drug Evaluation and Research, said in the statement.

The FDA hopes that the availability of a long-acting injectable drug for HIV prevention will increase the uptake of such medications in high-risk groups, the statement reads.

Pre-exposure prophylaxis (PrEP), meaning medications taken to prevent HIV, are recommended for about 1.2 million people in the US, and in 2020, about 25 percent of those individuals received a prescription for PrEP pills. That's up from only 3 percent in 2015, but "there remains significant room for improvement," the statement says.

Two clinical trials suggest that Apretude reduces the risk of HIV infection more effectively than the daily pill Truvada. The trials met the gold standard for these types of studies, because they were randomized and double-blind, meaning those who received the actual medication were randomly chosen and neither the doctors nor the patients knew who was receiving the real medication over the placebo.

The first trial included nearly 4,600 cisgender men and transgender women who have sex with men, Live Science previously reported. Those who took Apretude had 69 percent lower risk of getting infected with HIV than the participants who took Truvada.

The second trial, which included about 3,200 cisgender women at risk of acquiring HIV, found that those who took Apretude had 90 percent lower risk of getting infected with HIV, compared with participants who took Truvada, according to the FDA statement.

The trial participants who took Apretude did experience more side effects than those who took Truvada, including headaches, fever, fatigue, back pain, myalgia, rash and reactions at the injection site, according to the statement.

As of December 20, Apretude has been approved for use in at-risk adults and adolescents weighing at least 77 pounds (35 kilograms), according to the FDA statement. Patients have the option to take an oral formulation of cabotegravir, called Vocabria, daily for four weeks prior to starting the injections, to see how well they tolerate the drug.

Patients should be tested for HIV and confirmed negative before starting Apretude and should be confirmed negative before each injection, to avoid the risk of developing drug-resistant HIV.

"Drug-resistant HIV-1 variants have been identified with use of Apretude for HIV-1 PrEP by individuals with undiagnosed HIV-1 infection," according to a statement from the drug's manufacturer, ViiV Healthcare.

"Individuals who become infected with HIV-1 while receiving Apretude for PrEP must transition to a complete HIV-1 treatment regimen."

Earlier this month, the CDC updated its guidance regarding how doctors should inform patients about PrEP, The Hill reported. The agency now recommends that health care providers inform all sexually active adults and adolescents about PrEP and offer the medications to all who ask for them, regardless of whether they report specific behaviors that would put them at high risk of HIV exposure. Apretude now joins the list of possible options that can be presented to these patients.

Apretude has a list price of US$3,700 per dose (or $22,200 per year, for six doses) and is expected to ship to wholesalers and specialty distributors in the US early next year, NBC News reported.

In July, the federal government mandated that most US insurance companies must cover Truvada and Descovy, as well as the lab tests and clinic visits needed to maintain the prescriptions, with no cost sharing; but as of yet, insurers are not required to cover all the costs of taking Apretude.

Related content:

7 revolutionary Nobel Prizes in Medicine

Medicine's journey through the body: 4 stages

The deadliest viruses in history

This article was originally published by Live Science. Read the original article here.