Pre-Exposure Prophylaxism (PrEP) for HIV | Truvada vs Descovy - What's the difference?


This article is for educational purposes only and is not intended to promote any one drug over another. It was written to address some of the differences between the two major drugs used to treat PrEP (Pre-Exposure Prophylaxis) for HIV (Human Immunodeficiency Virus) in both heterosexual and homosexual transmission. PrEP medications are taken in advance of intimate sexual contact between two or more individuals, in order to prevent the transmission of HIV. These medications must be taken every day to work to prevent transmission of the HIV virus through sexual contact. The two major drugs at the time of this writing for PrEP are Truvada and Descovy. Truvada is going off patent a year early and hence will be generic this year, as Gilead, Truvada’s manufacturer, has reached an agreement with Teva Pharmaceuticals to produce it in generic form. Descovy is still under patent with Gilead. (Read on for the more insight into this.)

These PrEP drugs should NOT be confused with drugs that treat a person who already has a confirmed diagnosis of HIV. To go on any of the PrEP drugs, it must be remembered, that one must first test negative for HIV. BEWARE THAT IT IS DANGEROUS TO GO “ON-LINE” AND HAVE ONE OF THESE DRUGS PRESCRIBED FOR YOU IF YOU HAVE NOT FIRST HAD A NEGATIVE HIV TEST, even if you are “young and healthy”. However, Telemedicine physicians licensed to practice by a state Medical Board can prescribe a PrEP drug for you without a face-to-face exam, but the lab-work is essential. In cases of undiagnosed HIV infection, these drugs will not treat the infection.

Treating confirmed HIV infection with a combination of various anti-viral drugs should usually be done in conjunction with an infectious disease physician, whereas properly prescribed PrEP medications do not need such a specialist to be prescribed as long as a negative HIV is documented first.


HIV is a sexually transmitted virus that can call the disease AIDS (Auto-Immune Deficiency Syndrome). The virus can be found in the blood, semen, rectal fluid, and breast milk. It spreads when one of these fluids is exchanged from an infected individual to a previously non-infected person. Some ways that this transmission happens are:

· Anal, oral, or vaginal sex.

· Using a contaminated needle or syringe previously used by a HIV+ person.

· Pregnancy (mother to fetus), childbirth or even breast-feeding (mother to fetus).

· Rarely, small amounts of fluid exchange that can occur with deep kissing or oral sex

HIV can be transmitted via heterosexual or homosexual intimate contact as delineated above.

Both Truvada and Descovy are comprised of a combination of the same two active ingredients, emtricitabine and tenofovir, together in one tablet. So what’s the difference?

Truvada contains 200 mg of emtricitabine and 300 mg of tenofovir whereas Descovy contains 200 mg of emtricitabine but only 25 mg of tenofovir. [Some attorneys are attempting to launch a lawsuit against Gilead related to adverse effects of Truvada, which were thought to be primarily due to the high dose of tenofovir. These side effects are related to kidney function and bone metabolism.] That is why the dosage of the tenofovir component in Descovy has been reduced, and this new formulation is under patent by Gilead under the brand name Descovy. Descovy is thought to be just as effective at PrEP as the Truvada formulation, but with less risk of kidney and bone metabolism side effects.

In terms of dosage, both drugs are taken once a day and must be taken every day to be effective in greatly reducing the risk of acquiring HIV infection, along with the use of barrier protection (e.g., condoms). Once a negative HIV test result is obtained, either drug can be started and must be taken daily to confer protection against contracting HIV. At least every 3 months of taking the drug, a repeat HIV test, as well as tests for Hepatitis, liver function and kidney function tests should be performed before the drug is renewed. These should be repeated periodically while on the drug. If taken as prescribed and combined with barrier protection, and with close follow up and laboratory surveillance, these drugs are effective in prophylaxing against HIV and are generally well-tolerated. Missing doses sporadically may cause the medication to be ineffective and not protect the person from contracting HIV.

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