ARV side effect cause for concern - experts

The dangerous side effects of an anti-AIDS drug commonly used in South Africa have forced medical experts to re-evaluate the limited treatment options available in developing countries.

Stavudine (also known as Zerit or d4T), used in South Africa's free antiretroviral (ARV) rollout programme, could cause lactic acidosis in some people, particularly overweight women.

Dr Henry Sunpath, citing his study at McCord Hospital, in the port city of Durban, told IRIN/Plusnews that 14 of the 849 people monitored for the condition over a six-month period had developed it.

"Three of the 14, including a nurse on our staff, died as a result of this side effect.

It certainly is cause for concern, and calls for closer monitoring of patients for adverse reactions to the drug," said Sunpath.

Lactic acidosis is a rare and serious illness, caused when lactic acid is not eliminated from the body and instead builds up in the blood and cells, causing abdominal pains, nausea, vomiting and muscle weakness. It is linked to nucleoside analogues (a class of drugs that prevent healthy cells from becoming infected with HIV), although the condition may occur more commonly with Stavudine.

"But not everyone is at risk.

A genetic predisposition might be one of the causes, as was found to be the case in the United States. Similar studies to monitor lactic acidosis ... revealed that African Americans were more at risk than the rest of the population," Sunpath commented.

The use of the medication as a first-line treatment for HIV-positive people was phased out in the US after the country's Food and Drug Administration approved its replacement, Tenofovir, as a safer alternative.

"At the moment we are only able to replace d4t in lactic [acidosis] patients with AZT [Zidovudine].

While this is our best successful option, Tenofovir does have more advantages in that its side effects are lower, and it can be used for a longer period before a patient naturally develops resistance to it," Sunpath said.

More than three years after Gilead Sciences, which manufactures Tenofovir, first announced its 'Access Programme' for this key anti-AIDS drug, it is still largely unavailable in poor nations. International groups have often expressed concern that newer drugs are not reaching people in developing countries.

The cost of Tenofovir has been the main obstacle to access in Africa, but local drug firm Aspen Pharmacare was recently awarded a licence by Gilead to manufacture and distribute a generic version of the drug in 95 countries, including South Africa.

"Although minimal, the side effects of d4t in certain HIV-positive patients are not taken lightly.

We expect that once it hits the shelves, Tenofovir will help tackle that concern," said Stavros Nicolaou, a senior executive at Aspen.

He confirmed that his company had filed for registration of the drug with the South African Medicines Control Council (MCC) more than seven months ago.

In the meantime, Sunpath recommended AZT as a replacement for d4t in patients suffering lactic acidosis, as well as those beginning ARV therapy for the first time.

//This article is part of an IRIN/PlusNews series on HIV/AIDS and communities of humanitarian concern.

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