Throbbing, itching, aching, stabbing, stinging, pounding, piercing. Pain comes in a range of unpleasant flavors. But all pain has one thing in common: those who endure it want it to stop.
Yet the most widely used analgesics today are essentially folk remedies that have served for centuries: morphine and other opiates derive from the opium poppy, and aspirin comes from willow bark. Although these treatments can give relief, each has its limitations. Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, cannot ease the most severe types of discomfort. And even opiates, generally the strongest medicines, do not work for everyone. Moreover, they can have serious side effects, and patients tend to become tolerant to them, requiring escalating doses to get any relief at all.