Enlarge / An Eli Lilly & Co. Zepbound injection pen arranged in the Brooklyn borough of New York, US, on Thursday, March 28, 2024. (credit: Getty | helby Knowles)

Pharmaceutical giant Eli Lilly earned praise this week with an announcement that it is now selling starter dosages of its popular weight-loss drug tirzepatide (Zepbound) at a price significantly lower than before. But the cheers were short-lived as critics quickly noticed that Lilly also quietly raised the price on current versions of the drug—a move that was notably missing from the company's press release this week.

In the past, Lilly sold Zepbound only in injectable pens with a list price of $1,060 for a month's supply. Several dosages are available—2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, or 15 mg—and patients progressively increase their dosage until they reach a maintenance dosage. The recommended maintenance dosages are 5 mg, 10 mg, or 15 mg. The higher the dose, the more the weight loss. For instance, people using the 15 mg doses lost an average of 21 percent of their weight over 17 months in a clinical trial, while those on 5 mg doses only lost an average of 15 percent of their weight.

On Tuesday, Lilly announced that it will now sell Zepbound in vials, too. And a month's supply of vials with the 2.5 mg doses will cost $399, while a month's supply of 5 mg doses is priced at $549—a welcome drop from the $1,060 price tag. These prices are for a self-pay option, meaning that patients with a valid, on-label prescription can buy them directly from Lilly if they have no insurance or have insurance that does not cover the drug.

Enlarge (credit: Getty | Spauln)

The dose makes the medicine—and for many critical prescription drugs, the dose depends on a patient's body weight. Usually, this is not a problem; weight changes large enough to significantly affect dosages often occur gradually, over periods long enough for doctors to notice and adjust prescriptions. But, in the era of new weight loss drugs, that may no longer be the case.

In a cautionary tale published Monday in JAMA Internal Medicine, researchers at the University of Colorado reported the case of a man who lost nearly 30 percent of his body weight in a six-month period using a new weight loss drug. Then, he showed up at an emergency department with heart palpitations, excessive sweating, confusion, fever, and hand tremors. Tests indicated the man had atrial fibrillation, an irregular heart rhythm that can lead to heart failure and stroke without treatment.

The 62-year-old had no history of atrial fibrillation, but he had previously been diagnosed with obesity, Type 1 diabetes, and hypothyroidism (a condition in which the thyroid gland does not produce enough thyroid hormone). For his hypothyroidism, he took levothyroxine, a synthetic thyroid hormone that is dosed by weight.

Enlarge / Wegovy is an injectable prescription weight-loss medicine that has helped people with obesity. (credit: Getty | Michael Siluk)

The US Food and Drug Administration has approved two injectable versions of the blockbuster weight-loss and diabetes drug semaglutide (Wegovy and Ozempic). Both come in pre-filled pens with pre-set doses, clear instructions, and information about overdoses. But, given the drugs' daunting prices and supply shortages, many patients are turning to imitations—and those don't always come with the same safety guardrails.

In an alert Friday, the FDA warned that people are overdosing on off-brand injections of semaglutide, which are dispensed from compounding pharmacies in a variety of concentrations, labeled with various units of measurement, administered with improperly sized syringes, and prescribed with bad dosage math. The errors are leading some patients to take up to 20 times the amount of intended semaglutide, the FDA reports.

Though the agency doesn't offer a tally of overdose cases that have been reported, it suggests it has received multiple reports of people sickened by dosing errors, with some requiring hospitalizations. Semaglutide overdoses cause nausea, vomiting, abdominal pain, fainting, headache, migraine, dehydration, acute pancreatitis, and gallstones, the agency reports.

Enlarge / Ozempic is a GLP-1 drug for adults with type 2 diabetes. (credit: Getty | Steve Christo)

For patients with Type 2 diabetes, taking one of the new GLP-1 drugs, such as Ozempic, is associated with lower risks of developing 10 out of 13 obesity-associated cancers as compared with taking insulin, according to a recent study published in JAMA Network Open.

The study was retrospective, capturing data from over 1.6 million patients with Type 2 diabetes but no history of obesity-associated cancers prior to the study period. Using electronic health records, researchers had follow-up data for up to 15 years after the patients started taking either a GLP-1 drug, insulin, or metformin between 2008 and 2015.

This type of study can't prove that the GLP-1 drugs caused the lower associated risks, but the results fit with some earlier findings. That includes results from one trial that found a 32 percent overall lower risk of obesity-associated cancers following bariatric surgery for weight loss.