-- not just incrementally expand it to the whole population. Answer contributed by David Himmelstein and Steffie Woolhandler What is driving an epidemic of adverse reactions to medications in the U.S.? What impact could a single payer system have on this epidemic? There is an epidemic of adverse side effects because of the activities of the pharmaceutical manufacturers, who seek to maximize profits regardless of the risks to patients through a variety of means such as: promoting drugs to physicians for uses they are not approved for; giving physicians incentives to prescribe medications that are more costly than alternatives; developing new medications under patent that are no better - and often worse - than older, cheaper treatments; and $4 billion in direct to consumer advertising annually. The drug companies are much stronger under multi-payer systems than single-payer systems. Single-payer systems are stronger, more active buyers or payers. They demand evidence that new drugs are clinically better, not just better than placebos and against surrogate end points. They have a societal charge to maintain and restore the health of all residents, not just the subscribers for a given insurer or payment plan. Companies are single-minded in maximizing sales and profits and thus play payers off each other. Research shows that 60% of pharmaceutical revenues are derived from new drugs with few advantages, not from breakthrough drugs - a strong incentive for companies to churn out scores of new drugs of little benefit but with under-tested risks of harm. Answer contributed by