Drug interactions
Anti-HIV drugs can interact with medicines used to treat other conditions.
This can mean that levels of antiretrovirals or other drugs are increased or decreased. This can mean medicines don’t work properly or are more likely to cause side-effects.
As well as being used to control seizures, this type of medicine is also used to treat conditions which are more common in people with HIV, for example peripheral neuropathy. In addition, they can be used as a therapy for bipolar mood disorder.
The guidelines identity a number of possible interactions and recommend the following dose adjustments:
- Doses of the anti-HIV drug Kaletra (a combination pill containing lopinavir and ritonavir) may need to be increased by 50% when taken with phenytoin (Epanutin) to maintain blood levels of Kaletra.
- Doses of the anti-HIV drug AZT (zidovudine, Retrovir) may need to be reduced if taken with valproic acid (Depakote).
- People taking the anti-HIV drug atazanavir (Reyataz), boosted with another anti-HIV drug, ritonavir, may need to increase dosage of lamotrigine (Lamictal) by 50% to maintain blood concentrations of lamotrigine.
It is important to tell your HIV doctor or pharmacist about any other drugs you are taking – including contraceptives, drugs prescribed by another doctor (such as your GP or another specialist), drugs you have bought over the counter, alternative therapies or recreational drugs.
To help you prepare for your next appointment with your HIV doctor, we’ve put together a tool called Talking points, which you can access online at www.aidsmap.com/talking-points
Vitamin D supplements
There is currently little evidence that taking vitamin D supplements has any benefit for people with HIV, researchers have concluded.
It is now well known that many people with HIV have low levels of vitamin D.
The vitamin plays an important role in keeping the bones healthy, and reduced bone mineral density is also common in HIV-positive people. Therefore, HIV care now often involves routine monitoring of vitamin D levels and the use of supplements if levels of the vitamin are found to be deficient.
Researchers from the UK wanted to see if this strategy had any value. They therefore reviewed the results of studies involving people with HIV that looked at vitamin D levels, bone loss and fracture rates.
These showed that between a quarter and two-thirds of people with HIV had vitamin D deficiency. But major causes were similar to those seen in the general population and included being of black or Latin ethnicity and low exposure to sunlight.
A number of HIV-related factors were also important, and these included use of antiretroviral drugs and a low CD4 cell count.
Starting treatment with a combination that included efavirenz (Sustiva, also in the combination pill Atripla) was associated with falls in vitamin D level. But these were small and their significance is unclear.
Initiating HIV treatment also resulted in loss of bone density. This was most pronounced in the first six months of treatment and then stabilised. Nevertheless, the reduction was comparable to that seen during the first year of the menopause.
However, it’s still unclear if this has any day-to-day significance. The researchers found that fracture rates were increased in people with HIV. But most of these were fractures associated with accidents, rather than fractures caused by bone fragility.
Nor was there any substantial evidence that taking vitamin D supplements had any long-term benefits.
Lipodystrophy in children
Effective HIV treatment means that many HIV-positive children now have an excellent prognosis.
However, some antiretroviral drugs can cause long-term side-effects.
One of the most distressing is called lipodystrophy. It involves disturbances in the way the body stores and metabolises fat. This can include either fat accumulation around the belly, back of the neck and breasts, or fat loss from the face, limbs and buttocks, or a combination of both. There can also be increases in blood fats.
A lot is known about the prevalence and causes of this syndrome in HIV-positive adults. But less is known about lipodystrophy in children.
The European researchers found that 56% of children in the study had some form of lipodystrophy and that 42% had body fat changes.
HIV treatment appeared to be a cause, especially the use of the older anti-HIV drug d4T (stavudine, Zerit). This drug is no longer used in long-term HIV treatment in the UK because of its side-effects.
The investigators were concerned about the possible consequences of the high prevalence of lipodystrophy observed in their patients. “Several studies have reported a negative impact of body fat changes on self-esteem and psychological profile in HIV-infected adults…little is known about the impact on children and adolescents, but this is likely to be an issue for adolescents, given that this is a time when self-image is important.”
Sexual health
They found that even when people took high doses of aciclovir (Zovirax) and valaciclovir (Valtrex) they still shed HSV-2 (the virus that causes genital herpes) in short episodes lasting up to 12 hours.
In most instances, these short bursts of viral replication didn’t involve symptoms. However, levels of the virus were at potentially infectious levels.
The researchers conclude, “Suppressive therapies with greater potency, including antiviral drugs or immunotherapy in the form of therapeutic vaccines, are needed to provide substantial public health benefits.”