Questions and Answers with NAM • Keith Alcorn, senior editor, NAM
Contraception and HIV drugs
I’ve started a relationship with an HIV positive man
and we’ve decided we don’t want to use
condoms anymore. Having said that, I don’t want to become pregnant either.
I’m wondering whether the contraceptive pill is a good idea, what with
the anti-HIV pills I have to take.
If you aren’t using a barrier method of contraception like a condom
or diaphragm, it’s advisable not to take the contraceptive pill if your
drug combination includes nevirapine, efavirenz, atazanavir, lopinavir or
fosamprenavir. These drugs reduce levels of the contraceptive pill in your
body, therefore increasing the chances of you becoming pregnant. If you take
any of these drugs, it’s recommended that you also use a barrier method
of contraception in addition to the pill.
I’m taking efavirenz.
It’s particularly important you use a barrier method of contraception
if you are taking efavirenz, because this drug can cause birth defects during
the first three months of pregnancy, and whatever you might think about not
wanting children now, many women feel differently when they realise they are
pregnant.
Changing your treatment may affect your contraceptive options. If you need
to take lopinavir you will not be able to take the contraceptive pill. If
you take saquinavir you will not be able to use the combined pill (which contains
oestrogen and is the most commonly prescribed form of the pill) or the contraceptive
patch. Instead you will have to use the mini-pill, which is slightly less
effective, or injections of either Depo-Provera or Noristerat.
Are there any other options?
A contraceptive implant in the womb may be a better option, since the implant
releases the hormone progestogen directly to the ovaries, and will not be
affected by the presence of an anti-HIV drug in the blood. This device is
called an intra-uterine system, and seems to improve the symptoms of heavy
periods, too.
Some clinics give the injectable contraceptive Depo-Provera to women taking
anti-retrovirals but give the injections more often than the recommended interval
of 12 weeks. It’s hoped that this will reduce the risk that contraceptive
levels will fall too low as a result of any drug interaction.
Can I change to any drugs that don’t interfere with the contraceptive
pill?
Your choice is limited. The nucleoside analogues like AZT, 3TC and tenofovir
do not interact. Saquinavir and ritonavir do not interact with progestogen-based
contraceptives, so the mini-pill, implants or injections would be options
if you took these drugs. However, you have to weigh up which is more important:
being able to take a convenient HIV drug once a day, or having a form of contraception
you feel confident and comfortable using.
What’s the risk of falling pregnant if I decide to use a contraceptive
pill alongside efavirenz?
It’s difficult to say because there hasn’t been enough research.
One study that looked at the medical records of 88 women in one HIV clinic
using hormonal contraception found 11 became pregnant. Eight of these women
were taking nelfinavir, a drug not prescribed much any more, but two were
taking efavirenz, so for a surprisingly high proportion of women, the contraceptive
pill was not enough.
• NAM’s next forum is on 1 August. Dr Mike Youle will feedback
from the Rio HIV conference. The forum will be in Room B35, Birkbeck College,
Malet Street WC1, (next door to the University of London Union) from 7pm until
9pm. Entrance is free. For more information, call NAM on 020 7840 0050.
• NAM provides information to help you think about your use of
HIV treatments, but this is not intended to replace discussion with your doctor.
Visit NAM at www.aidsmap.com
