The medication Irbesartan tends to be a low-cost solution for high blood pressure. But recently, the price skyrocketed — but only in the 150 milligram dose, and only (according to our quick review of prices) at Costco.

First, let’s repeat the mantra of every cost-conscious patient: in the healthcare marketplace, you should get used to asking what things cost. We have a number of tools at clearhealthcosts.com; there are also other transparency sources, like Dr. David Belk, who attacks health-care pricing anomalies over at truecostofhealthcare.org. Belk — an Alameda, Calif., physician – alerted me to the price changes in Irbesartan, one drug that shows how prices can change rapidly on a monthly basis.

The price for a 150 mg dose jumped recently, which Belk heard about when a patient e-mailed him saying the price was off the charts. But only for a particular dosage.

Our information comes from the Costco price list on the Costco website, Dec. 1, 2013, showing 150 mg of Irbesartan at $93.96 for 30 pills, and 300 mg of the same drug at $12.46 for 30 pills. That’s right: $93.96 for 150 mg, and $12.46 for 300 mg.

For reference, we also looked at a GoodRx price list, also from Dec. 1, when prices ranged from $14.07 to $75 for 30 days. CVS has a 30-day supply for $28.41.

Why Did the Price Jump?

As Belk explains it, price jumps like this one can happen as a result of the pharmacy following a doctor’s orders, and also the pricing policies of suppliers:

“When a doctor writes a prescription, the pharmacy is obligated to fill the specific drug and dose the doctor prescribes. The only substitution they’re allowed to make is generic for brand name. Also, once a drug goes generic, it’s much easier to prescribe because we don’t need to have it authorized. Another factor in this is the fact that pharmacies don’t ask for price quotes before buying medications. They just assume a medication will be about the same price as it was the last time they purchased it.”

This assumption means a price increase gets passed on to patients, Belk explains:

“Here’s what happens: The pharmaceutical company decides to raise the price of one of their formerly inexpensive medications to about 30 times the previous price. The pharmacy only finds out about this after they get the shipment of the medication so they get stuck with this huge bill. Doctors and patients are completely unaware that 75 & 300 mg Irbesartan (as well as any dose of Losartan, a similar drug) are many times cheaper than the 150 mg dose (you could take two 75 mg pills a day and save hundreds of dollars). When the doctor writes ‘Irbesartan (or Avapro) 150 mg’ that’s what gets filled and either the patient or the pharmacy gets stuck with the bill. The same thing happened with doxycycline last spring and glyburide a few years ago.”

In early October, he says, the 150 mg pill cost the same as the 75 mg dose.

Who Pays When the Prices Skyrocket?

While you might assume that price increases like this one will hit insurance companies and the insured similarly, you’d be wrong.

“As with most things in healthcare, the patient’s insurance is usually off the hook for this price hike because they have a prearranged deal with the pharmacy for how much, if anything, they’ll reimburse for a drug,” Belk added. “They have no reason to offer a penny more when the price of the drug skyrockets unexpectedly. The pharmaceutical company makes a huge profit on that one drug for a short time (usually several months) and no one outside of pharmacies and a few uninsured patients ever notice.

“My suspicion is that pharmacies aren’t complaining much yet because it still happens only occasionally and complaining about it would only bring more attention to the fact that these medications are extremely cheap. Remember, most chain pharmacies are still trying to maintain the illusion that you’re getting a deal when you have a $10 monthly copay for your generic medication. This is why it would be great to have the price of all medications posted all of the time. Imagine walking into a grocery store and seeing that the price of ground beef is $50 a pound. How quickly would you decide to have chicken instead of hamburgers tonight? Unfortunately, you can’t do that with prescription medications — yet.”

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