THE DRUGS DO WORK

People who need more and more morphine to get a painkilling effect could
soon get back their sensitivity to the drug, making every dose almost as
good as the first.

Ironically, it's thanks to a drug that's used in high doses to stop opiates
like heroin and morphine from working at all. But in tiny doses the same
drug makes opiates more effective, according to Khem Jhamandas from Queen's
University in Kingston, Ontario.

In rats that had built up tolerance to morphine, a small shot of naltrexone
made their sensitivity to the drug rocket to 90 per cent of their original
response (Journal of Pharmacology and Experimental Therapeutics, vol 300, p
588).