The AIDS drugs Viracept, by Roche's laboratories have caused panic among the users who feel that the drug may not be safe due to contamination. There are many HIV-positive Zambians on the antiretroviral therapy.
The HIV drug has been recalled after a "human error" led to a higher than normal level of a chemical which can cause cancer. The drug Viracept, whose generic name is nelfinavir, was recalled after tests on batches revealed higher than normal quantities of methane sulfonic acid ethyl ester.
Roche, the Swiss company that manufactures the drug promptly recalled the drug from the European Union market after they found the contamination while investigating reports from patients that the Viracept tablets they were taking had an unusual smell.
The company in a statement said that the contamination had been caused by an interaction between two chemicals, one of them a cleaner, in a vessel in which the product was made.
The contaminant can cause cancerous tumors and genetic mutation that could harm unborn children if used during pregnancy.
Purity Mwamba, an HIV-positive housewife in the capital, Lusaka, said: "I may not be on Viracept, but I am deeply concerned as a person living with HIV and on ARVs [antiretroviral drugs]. If Viracept could be contaminated, other ARVs could be. We are therefore demanding an explanation from the government."
Zambia's health minister, Brian Chituwo, last week announced the immediate discontinuation of the drug, mainly used in second-line treatment, and ordered health workers to explain the incident to affected people.
About 1.6 million of Zambia's 11.7 million people are infected with HIV, but only 100,000 are currently receiving treatment at state health facilities and about one percent of them are taking viracept.
Viracept was introduced by Roche in 1998 as one of a class of ARV drugs called protease inhibitors, which prevent newly reproduced viruses from infecting other cells, thus slowing the spread of the HI virus in the body.
Roche said it was establishing Viracept patient registries for patients who may have been exposed to elevated levels of EMS as well as pregnant women and all children who have ever been exposed to Viracept, including those exposed in utero.
William Burns, chief executive of the pharmaceuticals division, said: "We take the welfare of patients extremely seriously. With the knowledge we have to date, we consider the risk to patients to be low, however we want to be sure patients can be followed and these registries will allow us to do just that.
"The root cause of the elevated levels of impurity observed recently has been identified and we are following up on the agreed actions with EMEA."
Roche said the European Medicines Agency has suspended the company's license in Europe for its AIDS virus treatment, Viracept.
Samuel Mpuka, executive director of the Churches Health Association of Zambia, an umbrella organization for church administered health institutions, said "Government should strengthen quality assurance mechanisms in this country - maybe there are many drugs that we are taking without actually ensuring their quality. People should know what they are taking."
Minister Chituwo said all HIV-positive patients on Viracept would be checked by healthcare providers before being switched to other drugs. "Patients should not unilaterally decide to change drugs on their own, as the effects may be fatal," he cautioned.
There are fears that some patients will stop taking Viracept before health workers determine the best replacement drug, and interruptions in treatment can lead to the development of drug resistance.