Drug Synergism refers to the enhancement in action or effect of a particular drug than the individual effect of both the drugs combined. The phenomenon could be exploited in the present scenario where the avian bird flu is posing a serious threat across different regions of the globe.
Tamiflu is a prescribed drug for seasonal flu, because it will be a first line of defense if the H5N1 bird flu circulating in Asia and reported in other areas mutates into a human pandemic strain. More than 60 people have died from the H5N1 strain in Asia. Medical experts fear it could spark a global pandemic if it mutates into a highly infectious virus in humans.
President George W. Bush asked the U.S. Congress for $7.1 billion on Tuesday to prepare for a pandemic flu, including $1.2 billion for 20 million doses of a vaccine against H5N1 bird flu.
Joe Howton, a medical director at the Adventist Medical Center in Portland, Oregon believes probenecid, a treatment for gout that is used with some antibiotics to boost effectiveness, could have a similar impact with Tamiflu. The idea stuck him when he noticed that giving Tamiflu with probenecid doubles the number of hours its active ingredient is in the blood.
Probenecid is used for the treatment of Gout and works by preventing the drugs from being removed from the body by the process of excretion. In other words it increases the bioavailability of the drugs. The effectiveness of the drug combination against a pandemic strain has not been established. However, it is considered the best option until a vaccine can be developed.
The move also seems sensible enough particularly when Governments are stockpiling Tamiflu (that is in scarce supply) to manage influenza pandemic in case the need arises. The acute shortage can be better handled with the innovative proposal. If it were proved right, half a dose of Tamiflu with probenecid would be as effective as a full dose without it.
But Roche, the manufacturer of the drug said it could not advocate combined treatment because of the lack of clinical data and regulatory approval. Given where we are, with the potential for a pandemic, the clearest vision we can have is to dramatically increase the availability of this drug and make all information available, said David Reddy, Roche's influenza pandemic task force leader.