Guidelines for post-exposure prophylaxis

Published: 07 April 2009
  • The UK Chief Medical Officer has requested that hospitals and primary care trusts make PEP available following sexual exposures.
  • UK guidelines recommend PEP following specified high-risk sexual exposures, but not following any unprotected penetrative sex.
  • UK, European and US guidelines all agree that PEP needs to be started as soon as possible after exposure.

A number of organisations have published guidelines on the use of post-exposure prophylaxis (PEP) to prevent HIV infection in exposed people. While guidelines for occupational exposure have been produced since 1996, recommendations for using PEP in people exposed through sexual contact, sharing injecting drug equipment, or through accidents outside the workplace were not formulated until nearly ten years later.

UK guidelines for PEP following occupational exposures are described in Needlestick injuries.

Despite differences in the precise recommendations on the risk associated with different types of exposure and the choice of drugs, the guidelines generally concur in the need to begin PEP as soon as possible after exposure for the best chances of success.

Related Links

UK non-occupational exposure guidelines for PEP

In February 2006 the guidelines from the British Association for Sexual Health and HIV (BASHH) were issued.1

The guidelines cover, among other things:

  • The scientific basis for recommending PEP
  • A guide to calculating the risk of a given exposure
  • The pros and cons of PEP as a prevention measure
  • Situations in which PEP is recommended
  • Recommended drug regimens
  • Pathways for access

PEP is recommended after sexual exposure, as follows:

Situations in which PEP would be considered

 

Partner status HIV+

Partner status unknown, but from a group or area of high prevalence (>10%)

Partner status unknown, not from a group or area of high prevalence

Receptive anal intercourse

Recommended

Recommended

Considered

Insertive anal intercourse

Recommended

Considered

Not recommended

Receptive vaginal intercourse

Recommended

Considered

Not recommended

Insertive vaginal intercourse

Recommended

Considered

Not recommended

Fellatio with ejaculation

Considered

Considered

Not recommended

Splash of semen into eye

Considered

Not recommended

Not recommended

Fellatio without ejaculation

Not recommended

Not recommended

Not recommended

Cunnilingus

Not recommended

Not recommended

Not recommended

Source: Adapted from BASHH 2006

When the source partner’s HIV status is not known, attempt should be made, where possible, to establish it as soon as possible, whilst following appropriate guidance on HIV testing and consent.

High prevalence groups notably include men who have sex with men and people who have immigrated to the UK from areas of high HIV prevalence, including sub-Saharan Africa.

Other factors to consider include whether either partner has a concurrent STI, the viral load in the HIV-positive partner, and whether there was sexual assault/trauma.

PEP “is only recommended where the individual presents within 72 hours of exposure,” the guidelines say, though they add that PEP “may be considered after this time if the exposure is ‘high risk’”.

Recommendations for PEP regimens are:

Recommended PEP combinations

One of the NRTI/NtRTI options:

Plus one of the protease inhibitor options:

AZT (zidovudine) and 3TC (lamivudine) in combined pill Combivir
or
D4T (stavudine, Zerit) and 3TC (lamivudine, Epivir)
or
tenofovir and FTC (emtricitabine) in combined pill Truvada
or
tenofovir (Viread) and 3TC (lamivudine, Epivir)

either an unboosted protease inhibitor:
Nelfinavir (Viracept)
or one of the protease inhibitors boosted with ritonavir:
lopinavir/ritonavir in the combined pill Kaletra
or
fosamprenavir (Telzir) and ritonavir (Norvir)
or
saquinavir (Invirase) and ritonavir (Norvir)

Source: Adapted from BASHH 2006

The nucleoside ddI is excluded for possible liver or pancreatic toxicity; abacavir (Ziagen) and nevirapine are excluded because of the well-known risk of acute hypersensitivity reactions to these drugs; and efavirenz (Sustiva) is excluded because it also causes rash and because it “causes short-term psychostimulation, which is possibly less well tolerated in anxious patients receiving PEP than in patients with established HIV infection”. 

It is recommended that PEP should be provided on a 24-hour basis at casualty departments.  Other recommendations on service provision include:

  • A mandatory baseline HIV test
  • Rapid GUM/HIV clinic referral
  • Weekly follow-up during PEP period
  • Three- and six-month HIV antibody test

The guidelines say that people who present repeatedly for PEP should not be penalised but should be “considered for repeat courses…according to the risk of HIV acquisition at the time of presentation”, particularly if their life situation means they are exposed to a degree of regular risk (such as the negative partner of a positive person, a sex worker, or someone unable to get their partner to use condoms). However, all repeat presenters should be encouraged to see a health adviser or psychologist. This recommendation contrasts with Australia’s ‘three strikes and you’re out’ policy. France and Spain allow a maximum of four and five repeats respectively.

The guidelines end by setting targets for PEP: at least 90% of prescriptions should be filled within 72 hours and should fall within the ‘recommended’ criteria; at least 75% of individuals should complete their four-week course; and at least 60% should get HIV tests done three and six months after presenting themselves.

PEP will never replace other HIV prevention strategies, the authors emphasise. They say: “It is crucial to consider PEP…as only one strategy in preventing HIV infection and, as such, it should be considered as a last measure where conventional, and proven, methods of HIV prevention have failed.”

When people are seeking PEP at A&E departments, it can be helpful to have a print-out of the guidelines in case of difficulties. When the GUM clinic is open, patients should tell reception they need to be seen immediately as an emergency appointment for PEP because of exposure to HIV. If the GUM clinic is not open, patients should go as soon as possible to the hospital's A&E department with the guidelines or take a piece of paper with the web address of the guidance.

The Terrence Higgins Trust national helpline, THT Direct, can advise patients who have problems getting PEP while they are still at the A&E or GUM. Patients can also ask the hospital worker to speak to THT Direct if this would help – 0845 12 21 200 (open Monday to Friday 10am to 10pm, Saturday and Sunday 12 noon to 6pm).

The 2006 UK Guidelines for PEP after sexual exposure can be read at http://www.bashh.org/documents/58/58.pdf.

UK government backing

In April 2006 all primary care and hospital trusts in the UK were sent a letter by the Chief Medical Officer, Sir Liam Donaldson, asking them to make sure that PEP against HIV infection through sexual exposure was routinely available in their areas.2 As the government’s top doctor, Donaldson is in a powerful position to influence health policy.

In his letter, Donaldson says:

“I would…ask you to ensure that PEP is part of the spectrum of sexual health services for your local populations.

“Provision of PEP for non-occupational exposure is not a replacement for evidence-based HIV health promotion, but it can have a contribution to make in preventing transmission of HIV.

“I would be grateful if you could bring this advice to the attention of your…clinical and public health teams so that they can take any necessary action to safeguard the health of your local population.”

However, Donaldson reiterated the 72-hour limit for PEP, saying that “after 72 hours it is unlikely to be effective,” which most health authorities will take as a limit to prescription.

References

  1. BASHH UK guideline for the use of post-exposure prophylaxis for HIV following sexual exposure. International Journal of STD & AIDS 17: 81-92, 2006
  2. Donaldson Sir Liam Improving the prevention and treatment of sexually transmitted infections (STIs), including HIV. 'Dear Colleague' letter, 6 April, 2006
This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.
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This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member of your healthcare team for advice tailored to your situation.