Nexium recently became much cheaper as Perrigo PLC began delivering its own over-the-counter generic version of esomeprazole magnesium earlier this month. Perrigo’s generic form of this popular and easily available heartburn medication received FDA approval on September 27; within a week, it was for sale at grocery and drug stores across the country as store brand products.

Perrigo is not the first drugmaker to attempt to cash in on Nexium’s popularity. Teva Pharmaceuticals was the first to get FDA approval for a generic version of prescription esomeprazole in January 2015. This was granted following a long legal battle with AstraZeneca, which held the original patent, and Ranbaxy, which had hoped to be the first to get their product onto pharmacy shelves when the patent expired. However, Perrigo is the first to get approval for a generic OTC version of Nexium.

The rush to produce generic esomeprazole is not surprising, given the revenues at stake. During its first five years on the market, Nexium sales brought in approximately $14 billion for AstraZeneca. When the patent expired in May 2014, AstraZeneca benefited from a bureaucratic roadblock at the FDA that delayed approval of a generic version for several months, enabling the company to squeeze out another $2.8 billion in revenue from Nexium that year. Since 2014, sales of OTC Nexium have made approximately $300 million a year for Pfizer, which has had exclusive rights to that version of the drug up until now.

Small wonder that smaller drug companies have been stampeding to get approval for their own versions. Esomeprazole’s popularity nonetheless seems odd in light of safety concerns that have come to light. In 2010, the FDA issued a warning over an association between frequent use of esomeprazole and increased risk of osteoporosis. Three years later, a safety notice was published on links to acute interstitial nephritis, an inflammation of the kidneys that can result in renal failure. Since that time, studies have made connections between esomeprazole and dementia, accelerated aging, increased risk of stroke and ulcerative colitis.

AstraZenca and six other drug companies that have marketed and manufactured proton pump inhibitors have been targeted in approximately 160 lawsuits, which were consolidated into multidistrict litigation (MDL) this past August. Plaintiffs allege that drug makers failed to warn patients and doctors of the dangers of kidney damage caused by the medication. Another MDL in which plaintiffs alleged bone injuries resulting from taking Nexium was closed three years ago when the judge ruled in favor of defendant AstraZeneca, citing an expert witness’ lack of qualification after granting the defendant’s motion to exclude her testimony.

AstraZeneca has wound up paying some hefty fines over the years in connection with Nexium. In 2015, the company paid out almost $28 million in penalties to the federal government to resolve allegations over deceptive marketing and physician kickbacks.

While there is little risk from the occasional use of proton pump inhibitors such as esomeprazole, it has been over-prescribed and over-utilized, often used to treat forms of heartburn for which the drug was not designed. Furthermore, PPIs such as Nexium do not offer immediate relief; according to Perrigo’s label, it can require anywhere from 24 to 96 hours for the medication to take effect.

Now that Nexium is more easily available and less expensive than ever before, it is vital for consumers to educate themselves about the numerous risks of taking the medication – and seek alternatives whenever possible.