Extended Release Drugs: Are They Right For You?

two prescription bottles with pills next to them
Katie Mui
Katie Mui is on the Research Team at GoodRx.
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One of the biggest downsides to taking a medication is side effects. After a dose of most drugs, the amount in the bloodstream spikes quickly, and then is flushed away within the course of a few hours. This means the amount of medicine in the body can vary at any point in time – and that spike can mean nasty side effects.

This problem is exactly what extended release (often noted as ER or XR) drugs were designed for. Typically taken once a day, these formulations keep the therapeutic dose at a steady level in the body for longer periods of time. So if you’re not getting the response you want from your current medication, it may worth talking to your doctor about trying an XR version. But bear in mind: the XR formulation can often be much more expensive.   

How do XR drugs work?

Drugs are usually broken down by the liver or kidneys, which means that after taking a dose, the body begins to naturally clear the medication from the system. As their name suggests, XR drugs typically include special coatings or mixers that make the drug take longer to clear from the body than ordinary or immediate-release (IR) drugs. Many popular drugs are now available in XR; there are well over 30 for pain alone.  

The graph below shows blood concentrations of the pain medication  Ultram (tramadol) after taking the immediate-release version (the white dots) every six hours, compared to the extended-release version (the dark dots), taken once every 24-hours.

Original data & chart published by DailyMed

Notice how the amount of drug in the bloodstream spikes for the IR drug. XR drugs eliminate this problem. Though they typically have a slightly slower onset compared to their IR counterparts, they maintain a more consistent level of the drug in your body, which could mean better treatment outcomes for longer periods of time while also lowering the occurrence of side effects. You also don’t have to take the drug as often, which may mean that you are less likely to forget to take your medication, especially when multiple doses are needed throughout the day.

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But about that price

So why doesn’t everyone just take the XR versions? Usually because of the price. Typically, XR formulations go through a new drug approval process with the FDA and are granted an additional patent as a new drug. This means that an XR version often doesn’t have a generic alternative, making it more expensive – and giving the drug company more time to make more money. This is why new extended-release versions of popular drugs turn up just before the patent expires (such as a new version of Lyrica). Some XR drugs – such as Adzenys or Concerta, for ADHD; or Zohydro for pain – can be nearly 10 times as much as generic alternatives.

But that’s not always the case. Extended release versions of alprozolam (Xanax) and metformin (Glucophage) are available in generic form, and aren’t much more than twice their regular version. Depending on how often you take your medicine, these versions can actually be cheaper than the old versions when you factor in the number of pills. Also keep in mind that some health insurance plans will only cover traditional immediate release drugs, so call your pharmacist or insurance provider – and check GoodRx – to check the price first.

Are XR drugs right for me?

If you are taking prescription meds every day, you should work with your physicians to ensure you’re taking the right form of medication for you. This may mean tracking your side effects and getting blood tests to get a better handle on what the highest and lowest concentrations of the drug is best for you personally. There’s also a small chance that your body might not be able to break down the slow release coatings or ingredients fast enough to hit that targeted therapeutic level in the bloodstream, so be sure to go back to your doctor if you don’t think it’s working.

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