Tablet Splitting When Two Halves Don't Equal a Whole

Republished July 31, 2024

Many medicines come in different strengths. For example, a medicine may come in both a 10 mg and a 20 mg tablet. Surprisingly, the higher dose often costs about the same as the lower dose. If the medicine is too expensive for some people, doctors may prescribe the higher dose and direct them to take half a tablet for each dose. However, splitting tablets may be risky for several reasons.

First, it is easy to become confused about the correct dose. For example, a woman was admitted to the hospital with heart and blood pressure problems. Her doctor found that she had been taking the wrong dose of her blood pressure medicine, lisinopril. She was supposed to be taking 5 mg twice a day, but the label on her prescription bottle said there were 10 mg tablets inside.

Initially, the woman had been taking a 20 mg tablet twice a day. When her doctor lowered the dose to 10 mg, she had the new prescription filled. But she cut the leftover 20 mg tablets in half and put them in the same bottle that held the 10 mg tablets. Later, her doctor lowered the dose to 5 mg twice a day. Instead of filling the new prescription for 5 mg tablets, she tried to find all the 10 mg tablets to split them in half, but some remained whole. No one could be certain of the dose the woman had been taking before she was hospitalized.

The accuracy of splitting tablets is also questionable. Some halves may have more medicine, others have less medicine, even if the tablet is scored (a depressed line in the center of a tablet that helps you split the tablet). Split tablets also crumble more easily, so there may be less medicine in the half tablet by the time you take it. Some tablets are too small or have an unusual shape so they can't be split evenly. Others are coated with a substance that helps to release the medicine slowly and should not be split. Splitting these tablets destroys the coating, so the medicine is absorbed too fast and can cause serious side effects.

Taking whole tablets that equal your exact dose is safest. However, tablet splitting may be necessary if the medicine does not come in the exact dose you need, or if you cannot swallow a tablet whole.

Here's what you can do: If you need to take half tablets, follow these guidelines:

• Ask first. Always check with your pharmacist to be sure it is safe to cut tablets in half. Not all tablets can be split. Some can cause overdoses or unwanted side effects if they are cut or broken.
• Know your limits. Tablet splitting requires sharp eyes and steady hands to do it correctly. Seek help from family members. Or better yet, ask your pharmacist to split the tablets for you.
• Get the right tools. Ask your pharmacist for a tablet-splitting device that can help improve the accuracy of cutting the tablet in half.
• Keep it clean. Wash and completely dry your hands before handling any tablets. Clean and dry the tablet-splitting device before use. After using the device, wash it to remove any leftover powder or particles. Be sure it is clean and dry before using it again.
• Keep them separate. It is never safe to mix different tablets together in prescription bottles, even if they contain the same drug but different doses. You could mistakenly split the wrong tablet or take the wrong one. Ask your pharmacist about getting additional medicine containers for your split tablets.

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