In all other developed countries, governments similarly use a variety of tools to make sure that drug manufacturers sell their products at affordable prices. In Germany, regulators set drug wholesale and retail prices. Across Europe, national health authorities refuse to pay more than their neighbors for any drug. In Japan, the price of a drug must go down every two years.

Drug prices in the United States are instead set in hundreds of negotiations by hospitals, insurers and pharmacies with drug manufacturers, with deals often brokered by powerful middlemen called group purchasing organizations and pharmacy benefit managers, who leverage their huge size to demand discounts. The process can get nasty; if mediators offer too little for a given product, manufacturers may decide not to produce it or permanently drop out of the market, reducing competition.

With such jockeying determining supply, products can simply disappear and prices for vital medicines can fluctuate far more than they do for a carton of milk. After the price of Abby Hayes’s Rhinocort Aqua nasal spray rose abruptly, it was unavailable for many months. That sent her family scrambling to find other prescription sprays, each with a price tag over $150.

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