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PrEP: Pre-Exposure Prophylaxis to Prevent HIV

What is PrEP?

PrEP (also called Truvada or Descovy) is a pill taken every day to prevent HIV infection from sex or injection drug use. PrEP stands for pre-exposure prophylaxis which means preventing HIV before being exposed to the virus. 

PrEP pillDoes PrEP work?

PrEP is highly effective for preventing HIV.

  • PrEP reduces the risk of getting HIV from sex by about 99% when taken as prescribed.
  • Although there is less information about how effective PrEP is among people who inject drugs, we do know that PrEP reduces the risk of getting HIV by at least 74% when taken as prescribed.
  • PrEP is much less effective when it is not taken as prescribed.   

How long before PrEP works?  

  • PrEP reaches maximum protection from HIV for receptive anal sex (bottoming) at about 7 days of daily use.
  • For receptive vaginal sex and injection drug use, PrEP reaches maximum protection at about 21 days of daily use.
  • No data are available for insertive anal sex (topping) or insertive vaginal sex.

Learn more about the  PrEP effectiveness estimate.

Is PrEP right for me?         

PrEP may be right for you if you test negative for HIV, and any of the following apply to you: 

You have had anal or vaginal sex in the past 6 months and you

  • have a sexual partner with HIV (especially if the partner has an unknown or detectable viral load),
  • have not consistently used a condom, or
  • have been diagnosed with an STD in the past 6 months. 

You inject drugs and you

  • have an injection partner with HIV, or
  • share needles, syringes, or other equipment to inject drugs (for example cookers).

You have been prescribed   PEP  (post-exposure prophylaxis) and you

  • report continued risk behavior, or
  • have used multiple courses of   PEP

If you are a woman and have a partner with HIV and are considering getting pregnant, talk to your doctor about PrEP if you're not already taking it. PrEP may be an option to help protect you and your baby from getting HIV while you try to get pregnant, during pregnancy, or while breastfeeding. 

Only you and your health care provider can determine if PrEP is right for you. This makes finding a health care provider who knows about PrEP and who is also someone you feel comfortable talking with a very important part of getting, and staying, on PrEP.

Where do I get PrEP?

Any doctor, nurse practitioner, or physician's assistant can prescribe PrEP. If you want to work with someone besides your regular provider, go to  to find a clinic near you.   Montana's Gay Health Task Force  has more information. Find PrEP near you.

How do I take PrEP?

Your provider will first make sure you are HIV negative. You will receive a 90 day supply, then need to come in every three months to check for any side effects. You will be tested for other STIs like syphilis or gonorrhea and continue to be tested for HIV. 

How do I pay for PrEP?

If insurance does not cover the costs, you may be able to enroll in the Montana PrEP Assistance Program through one of the participating providers listed below.  

Video: Start Talking, Stop HIV  

Watch this two minute video of different groups of men talk about PrEP. (English & Spanish). 

"PrEP is for everyone. Women, men, cisgender, transgender...Everyone."

"What does the H in HIV stand for? Human."

More Information

For Consumers
The Department of Public Health and Human Services cannot guarantee the accuracy of a non-state website.  - Click on the PrEP tab to find a PrEP provider near you. 
PrEp Locator  - from
National PrEP Locator  - from Emory University with CDC support

For Providers

Complete List of PrEP Best Practices  - from the CDC
National Clinician's Consultation Center (UCSF)
PrEPLine  855 448-7737    855 HIV-PrEP
Monday - Friday; 11am-6pm ET

Providers Affiliated with the Montana State PrEP Assistance Program 

This program is open to all clinics with licensed prescribers within the State of Montana. If you would like your clinic to be part of this program, contact 406 444-3565. 

Community Facility Name Address  Main Phone Number
1. Billings Planned Parenthood - West 1844 Broadwater #4
Billings, MT 59102
(406) 656-9980
2. Billings Planned Parenthood - Heights 100 W Wicks Ln
Billings, MT 59105
(406) 869-5040
3. Bozeman Bridger Care 1288 N 14th Ave
Bozeman, MT 59715
(406) 587-0681
4. Butte Butte-Silver Bow Family Planning 25 W Front
Butte, MT 59701
(406) 497-5020
5. Great Falls Planned Parenthood - Great Falls 211 9th Street South
Great Falls, MT 59405
(406) 454-3431
6. Havre Bullhook Community Health Center 521 4th Street
Havre, MT 59501
(406) 395-4305
7. Helena Planned Parenthood - Helena 1500 Cannon
Helena, MT 59601
(406) 443-7676
8. Helena PureView Health Center 1930 9th Ave
Helena MT 59601
(406) 457-0000
Contact: Marina Kuntz
9. Kalispell Flathead Family Planning 1035 1st Ave West - 3rd Floor
Kalispell, MT 59901
Contact: Shawna Himsl
10. Missoula Partnership Health Center 401 Railroad St. W
Missoula, MT 59802
(406) 258-4789
11. Missoula Planned Parenthood - Missoula 219 East Main Street
Missoula, MT 59802
(406) 728-5490
12. Polson Providence St Joseph Medical Center Six 13th Avenue East
Polson, MT 59860
(406) 883-7496
Contact: Michael Watkins, Pharmacy


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Contact information

Cogswell Building
Room C-211
1400 Broadway
Helena, MT 59620
(406) 444-3565

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