Guide to PrEP Dosage

Who Is PrEP Recommended For?

PrEP is recommended for sexually active people at medium to high risk of HIV infection as follows:

For men who have sex with men (MSM)

  • Episodes of condomless anal or intercourse with partners with detectable HIV Viral load, untreated HIV infection or unknown HIV status
  • Rectal Gonorrhoea, rectal Chlamydia or Syphilis in the past 3 months
  • Methamphetamine use
  • Any of the above and a likelyhood that this may happen again in the next 3 months (sustained risk)

For Trans & Gender Diverse People

  • Episodes of condomless anal or vaginal intercourse with partners with detectable HIV Viral load, untreated HIV infection or unknown HIV status
  • Rectal or vagina Gonorrhoea, Chlamydia or Syphilis in the past 3 months
  • Methamphetamine use
  • Any of the above and a likelyhood that this may happen again in the next 3 months (sustained risk)

For Heterosexual People

  • Episodes of condomless intercourse (CLI) with partners with detectable HIV Viral load, untreated HIV infection or unknown HIV status
  • At least one episode of condom less anal or vaginal intercourse with a homosexual or bisexual male with detectable HIV viral load, untreated HIV infection or unknown HIV status.
  • A female patient in a serodiscordant heterosexual relationship, who is planning natural conception in the next 3 months
  • At least one episode of CLI with a heterosexual partner, not known to be HIV–, from a country with high HIV prevalence

Screening Before Starting PrEP For All Dosage Regimes

Before starting PrEP all people should be screened as follows:

  • HIV status: Ensure that this person is HIV negative before starting PrEP. If there has been a high risk exposure 72 hours or less before review then offer PEP. If there has been a potential exposure to HIV more than 72h prior to review but less than 30-90 days careful monitoring of HIV status for the next 2-8 weeks is recommended.
  • Hepatitis B & C status.
  • Check of renal function with eGFR >60ml/min
  • Complete STI screening

Screening When Taking PrEP For All Dosage Regimes

No matter how a person is taking PrEP 3 monthly screening is recommended. The following testing is recommended:

  • HIV testing every 3 months
  • Renal function testing 3 months after starting and every 6 months if eGFR >90ml/min or every 3 months if < 25 years of age, >40 years of age or initial eGFR was <90ml/min when PrEP was started.
  • Full STI screening
  • Pregnancy testing in all females of child bearing potential

PrEP Dosage Regimes

Daily PrEP

Who Is Daily PrEP Recommended For?

  • Recommended for those with medium to high HIV infection risks as noted above.
  • Suitable for HIV negative women seeking to fall pregnant
  • Suitable for people who are Hepatitis B infected
    • Recommend review with ID specialist for all people with chronic Hepatitis B infection
    • ID review and care when ceasing PrEP due to risk of flare up of Hepatitis B

Starting Daily PrEP

  • Open discussion, education and consent with patient about risks and benefits of daily PrEP.
  • Standard pre PrEP screening as noted above
  • Initial script to be provided to patient for daily, continuing, oral dose of coformulated tenofovir and emtricitabine (TD*/FTC)(Truvada™ or generic equivalent)
  • 7 days of daily medication recommended to ensure protective levels of TD*/FTC before potential HIV exposure.

Screening While on Daily PrEP

  • Every three months as noted above

Cessation of Daily PrEP

  • Australian guidelines recommend continuation of daily PrEP for 28 days after last potential exposure to HIV. Some studies recommend only 7 days of PrEP may be required however this is a matter of debate in different guidelines and is worth discussing with your patient to help them decide. [1]
  • People infected with Hepatitis B may have a flare up of Hepatitis B viral load. Cessation of PrEP is best planned with review with ID specialist.

Holiday PrEP

Holiday PrEP is recommended for persons who may have an extended period of time where risk of HIV acquisition is higher and then return to a low level. Holidays may be an example when this style of regime may be appropriate.

Who is suitable for holiday PrEP?

  • Holiday PrEP is suitable for all people at medium to high risk of HIV infection over a medium to extended period of time.
  • Holiday PrEP is almost identical to daily PrEP with the exception of length of time a person is considered at medium to high risk of HIV infection.
  • Holiday PrEP may not be suitable for people living with Hepatitis B and consultation with an ID specialist is recommended due to risk of flare up of Hep B viral load on cessation of TD*/FTC

How to start holiday PrEP

Initiation of holiday PrEP is identical to starting daily PrEP:

  • Testing to ensure not HIV infected within 7 days of starting holiday PrEP.
  • Testing of renal function to ensure eGFR >60ml/min
  • Full sexual health screening including hepatitis B & C
  • Supply of 90 days of TD*/FCT as per PBS and Australian guidelines. If a person is going to be away from Australia longer than 90 days help ensure patient has access to medication as well as quarterly testing (HIV, renal function and STI screening) while away.

How to take holiday PrEP:

Source [1]
  • One tablet of TD*/FTC to be taken daily starting 7 days before potential HIV exposure, daily during period of risk and 7 to 28 days post last potential exposure to HIV when period of risk has ceased.
  • After completion of holiday PrEP full STI screening (HIV, Syphilis, Chlamydia / Gonorrhoea in all potential sites, Hepatitis C & Renal function recommended.

On Demand / Intermittent PrEP

Who is on demand PrEP suitable for?

  • On demand or intermittent PrEP is suitable for people who have infrequent episodes of risk of HIV infection.
  • Users of on demand PrEP do need to be able to predict sexual activity as preparation is required. If spontaneous sexual activity is more likely this person may be more suited to daily or holiday PrEP regimes that involve taking TD*/FTC on a daily basis during periods of risk.
  • Currently on demand PrEP is only studied in men who have sex with men (MSM) and transgender females and as such is not recommended for CIS gendered females, heterosexuals and transgender males.
  • Due to risk of reactivation of hepatitis B infection on demand PrEP is not recommended for people living with chronic hepatitis B infection.
  • PrEP on demand may also be suitable for people who have had side effects from daily PrEP such as nausea, diarrhoea or changes in renal function [2].

How is on demand PrEP started?

  • As with all PrEP regimes it is vital to ensure a person is HIV negative before starting any form of PrEP
  • Regular quarterly screening is recommended for HIV, renal function and complete STI screening including viral hepatitis for those at risk
  • Specialist review is recommended for people with eGFR less than 60ml/min
  • Patients are supplied with education on how to take PrEP on demand including importance of quarterly screening.
  • 90 day supply of TD*/FTC supplied as per PBS / Australian PrEP guidelines.

How to take PrEP on demand

  • If a person believes they may have an episode of risk they take 2 tablets of PrEP (TD*/FTC) 2 to 24 hours before intercourse.
  • If intercourse has occurred the person takes a single tablet of TD*/FTC every 24 hours till 48 hours has past since the last sexual intercourse.
  • If sexual activity is resumed within one week of last tablet of PrEP only 1 tablet loading dose of TD*/FTC is required. If sexual intercourse is resumed more than 7 days after last PrEP tablet then the 2 tablet loading dose is required as noted above. [2]

PrEP on demand screening

As with all PrEP regimes quarterly screening is vital with testing for HIV, Syphilis, Hepatitis C if appropriate, renal function and site specific Chlamydia/Gonorrhoea PCR (throat, rectum, cervix, urine).

[1] Sexual safety and HIV prevention in travel medicine: Practical considerations and new approaches
Vincent J. Cornelisse, Edwina J. Wright, Christopher K. Fairley, Sarah L. McGuinnessc.
Travel Medicine and Infectious Diseases. Dec 2018

[2] Australasian Society for HIV, Viral Hepatitis and Sexual Health Medicine HIV pre-exposure prophylaxis: clinical guidelines. Update April 2018. Edwina Wright, Andrew Grulich, Katy Roy, Mark Boyd, Vincent Cornelisse, Darren Russell, Darryl O‘Donnell, Bill Whittaker, Levinia Crooks & Iryna Zablotska
Journal Of Virus Eradication. April 2018