The use of opiates in general, and opioids in particular, is considered to be an effective treatment for arthritis, although it's less common than the use of anti-inflammatory drugs. Rheumatologists, or arthritis experts, are often more inclined to prescribe an opioid like morphine than an anti-inflammatory drug, since anti-inflammatory drugs can be accompanied by dangerous or even fatal side effects. However, many people are afraid of the "junkie" stigma that goes along with the use of prescription narcotics, including doctors.
While opioid drugs have changed over the years, the image of people becoming addicted to them hasn't. People are often afraid to start taking an opiod because they think they'll become dependent. Even when people agree to take them, they often take smaller doses than the doctor prescribed because they think they'll ward off addiction that way. Instead, the lower dose of drugs doesn't help them and their arthritic pain persists. But there are now time-release versions of narcotics to treat chronic pain that reduce the chance of addiction; they are administered by pill or patch and gradually make their way into the bloodstream to deliver a steady dose of pain relief. This type of long-acting drug doesn't offer the high that was once associated with a quick injection of an opioid, and it also doesn't feature a dramatic comedown after the drug wears off. The drawback to such drugs is that they don't completely wipe away the pain, although it's reduced enough so that you can function normally. Anti-inflammatory pain relievers typically don't get rid of the pain altogether, either.
Of course, addiction remains a possibility, as do other risky side effects. But many rheumatologists still consider opioids safer than over-the-counter pain relievers taken for a long period. Despite this, many doctors remain hesitant to prescribe opiate pain relievers to treat arthritis.