"I certainly did have a bad reaction and the more people I speak to the more seem to have had a problem with it. I started having extraordinary dreams and I found it very difficult to sleep. It is one of the conventional signs of a not very extreme reaction to the drug but I did not want to continue my travels like that," said Lady Jay, who will today issue the Government's new guidance on the drug.
The symptoms did not appear until after she, accompanied by her husband, Professor Michael Adler, the leading Aids specialist, on a tour of African countries, had arrived in Uganda. Professor Adler called colleagues at the Hospital for Tropical Diseases in London for advice and they recommended she switch to the less powerful combination of chloroquine and proguanil.
"That is what I had always taken before and what I have taken since. But the danger is people may stop taking anything and then expose themselves to the risk."
Package tourists to Africa and similar destinations are being advised to choose an alternative to the anti-malarial Lariam because of the risk of side effects from the drug.
The changed advice from the Government's Public Health Laboratory Service, follows growing concern about "neuro-psychiatric" symptoms linked with Lariam, which include convulsions, panic attacks, dizziness and insomnia.
A six-year-old girl died last year after taking the drug and hundreds claim to have suffered long term psychiatric effects and have formed an action group to seek compensation.
About 2,000 travellers from the UK develop malaria each year and between five and 10 die. Lariam, whose chemical name is mefloquine, is at least 90 per cent effective against the disease compared with chloroquine plus proguanil which is 70 per cent effective.
The guidelines, drawn up by the Malaria Reference Laboratory headed by Professor David Bradley and carried in the current issue of Communicable Disease Report, say that the risks of getting malaria have to be balanced against the risks of the drug. For people making a two-week visit to East Africa or the Gambia who take chloroquine and proguanil the risk of the disease is below one in 1,000 and Lariam is not justified.
However, for people staying for longer periods, Lariam is still the drug of choice. It is also the only drug effective in parts of China and Indo- China.