By guest blogger Michael R. Cohen: President of the Institute for Safe Medication Practices
You may have seen a brief article in today’s Inquirer about splitting prescription drug tablets. The article mentioned a Belgian study showing that measured doses of critical drugs cut in half could be off by 25% or more. So it seems reasonable to recommend what the article did - that tablets should never be split. Well, not so fast. There are in fact many reasons that doctors and pharmacists condone splitting tablets. So let’s take a closer look at the practice and discuss circumstances under which it can be done safely and effectively.
Most oral medications in tablet form are available commercially in the dosage strengths most commonly prescribed for patients. Occasionally though, the patient’s exact dose is not available commercially, so more than one tablet may be needed. Or, in some cases, just part of a tablet may be needed, which means it has to be split.
Another reason for splitting tablets is to keep costs down. For example, a medication might come in two different strengths and often 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.
Most people wouldn’t think twice about splitting medications that come in tablet form, but in some cases, doing so risks the possibility that the medication dose will be inaccurate, which could have clinical consequences. Studies like the one from Belgium do show that the actual dose in each half of a split tablet is often different, so doses are not equal. Some halves 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).
The process of splitting tablets also invites mistakes by some patients. For example a study done by the Veterans Administration showed that people often took too much medicine because they forgot to split their tablets. Pharmacists caught these mistakes because people came in too soon to refill their prescriptions. One in 10 people who forgot to split their tablets were harmed by this mistake.
Certain medications are not good candidates for tablet splitting. Warfarin, a blood thinner also known as Coumadin or Jantoven, is one example of a drug whose accurate dosing is crucial. Patients taking warfarin must be monitored carefully using a laboratory test called an INR to make sure the patient is within therapeutic range. A little too much daily from several uneven tablets could cause excessive bleeding. Too little of the drug could lead to blood clots.
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. To protect your stomach or to delay absorption and release the medication steadily over time, others are coated with a substance that won’t dissolve until it reaches your intestines. Splitting these tablets destroys the coating, so you might absorb the medicine too fast. Splitting other forms of time-release medications or tablets that aren’t scored could also present problems.
Taking whole tablets that equal your exact dose is safest. However, tablet splitting is appropriate and safe in many cases and may be necessary if the medicine does not come in the exact dose you need, or if you cannot swallow a tablet whole.
To stay safe if you need to take split 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 your pharmacist if you have poor eyesight or any condition that makes it hard to use your fingers and hands, such as arthritis or tremors.
• Get the right tools. Ask your pharmacist for a tablet-splitting device that can help improve the accuracy of each half tablet. The Belgian study showed that splitting tablets in this manner did result in more accurate dosing than manually breaking the tablet apart. Tablet splitters can be purchased in pharmacies or on-line.
• Keep it clean. Wash and completely dry your hands before handling any tablets out of the bottle. After using your tablet-splitting 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 medicine. Ask your pharmacist about getting additional medicine containers for your split tablets.
• Use our tool for medications that should not be crushed (or split): Do Not Crush Medications
For information on ISMP's consumer web site go www.consumermedsafety.org
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