Though I don't condone recreational marijuana use, nor have I dabbled in it myself, I do not know the pain of chronic illness. While pharmaceutical companies are creating painkillers in a lab, some patients may prefer a more natural approach. They may not want the extra chemicals in their already failing bodies. If a plant works just as well as the latest scientific breakthrough, why not use it as the natural alternative.
The morality of marijuana comes into question because of the abuse of this substance, though the substance in and of itself is neither good nor evil. Research shows promising results that may produce medical breakthroughs for many, if we would take more time to investigate medical marijuana. Biomaterials, such as marijuana interact with the body differently than synthetic drugs, such as modern day painkillers. The pharmaceutical industry creates many substances that cause harm with side effects, and can be highly influenced by monetary motivations. The morality question comes into play for both sides then. Is it moral to use a drug which may play a part in crime or is it a crime to push synthetic drugs which could harm the recipient all in the name of making money?
I'm not sure why the question is whether or not marijuana is a "moral" alternative to other pain killers. It is not really a question of morality. For some people, and for some conditions, marijuana is certainly a more effective and/or a more preferable alternative to traditional pharmaceutical pain killers.
Like other narcotics, I don't believe you should be allowed to work or operate machinery under the influence, but to those suffering with no other alternative, I think that it is a moral way to control chronic and severe pain. It should not be used as a party favor, of course.
While medical marijuana may help a patient, the side effects may lead to morally corrupt behavior. This includes short-term and long-term side effects. Panic, confusion and difficulty to understand new information may lead to making poor decisions for self and others the person may be responsible for. Shifts in mood and personality may also add to making poor decisions or taking part in bad behaviors.