5 medications you should never split in half for safety

Author: Liu Ziqi, Chief Pharmacist at The First Affiliated Hospital of Harbin Medical University. Review | Tang Qin, Director of the Science Popularization Department of the Chinese Medical Association, Researcher, National Health Science Popularization Expert. Planning | He Tong. Editor: Yang Yaping. Proofreading | Xu Lai, Lin Lin. Source: Popular Science China WeChat Official Account. The cover image and the images within the text are sourced from a licensed stock photo library. Reposting may lead to copyright disputes.

Recently, a news report detailed the case of a man who split a blood pressure medication in half before taking it. He was in a coma within thirty minutes but fortunately regained consciousness after emergency resuscitation.

Is there really a risk with common blood pressure medications? This is not an exaggeration; certain medications should not be split before consumption. Today, I will explain which types of medications should never be split. Taking these five categories of drugs in half could lead to mild ineffectiveness or, in severe cases, could result in poisoning. Everyone should be aware of this!

1. Controlled-Release Medications

Controlled-release tablets utilize specific technology to ensure that medications are released in the body at a consistent and ideal rate and dosage. This aims to maintain a sustained and stable concentration of the drug in the body.

Most standard medications exhibit a fluctuating concentration in the bloodstream, varying between high and low levels. In contrast, controlled-release formulations maintain a nearly constant drug concentration over time, making them particularly suitable for certain chronic conditions that require effective drug levels, such as cardiovascular diseases and hypertension.

Isn't that advanced? This sophisticated technology typically employs permeation pump or membrane control techniques for precise drug release. Controlled-release medications usually contain much higher dosages than standard drugs. For example, one controlled-release tablet of nifedipine is equivalent to the dosage of three regular nifedipine tablets. Taking it once a day is akin to taking three doses throughout the day, which helps reduce the frequency of administration and minimizes fluctuations in blood drug levels.

However, if we bite, crush, or grind controlled-release tablets, the technology is compromised. The medication will no longer release at the intended rate, and a large dose of antihypertensive medication may flood the system all at once, causing a sudden and severe drop in blood pressure with potentially dangerous consequences.

In addition to nifedipine extended-release tablets, common medications like glipizide extended-release tablets for diabetes and doxazosin mesylate extended-release tablets for benign prostatic hyperplasia and hypertension also require caution!

2. Sustained-Release Medications

Sustained-release drugs and controlled-release drugs differ slightly; they do not release at a constant rate but allow for a gradual release of the medication. The initial release is typically larger and then tapers off. By slowing down the drug release rate, the duration of its action is prolonged, thereby reducing the frequency of medication administration. Consequently, the dosage of sustained-release drugs tends to be higher than that of conventional medications.

Sustained-release medications are ideal when prolonged effects are required, such as in pain management and antibiotics. Similar to controlled-release medications, it is essential not to break, crush, or chew these pills, as doing so can damage the sustained-release structure, leading to a rapid release of a large dose and potentially triggering adverse reactions.

Examples of sustained-release medications include verapamil hydrochloride, felodipine, indapamide, potassium chloride, gliclazide, glipizide, buflomedil hydrochloride, diclofenac sodium, clarithromycin, pioglitazone, morphine sulfate, and lofexidine.

Most controlled-release and sustained-release medications should not be split; however, a few exceptions exist. These medications typically feature a score line on the tablet that makes splitting easier. While these can be divided, it is crucial not to chew or crush them. Instructions often specify if a medication can be split, so always read the label carefully and follow your doctor’s advice.

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3. Enteric-Coated Preparations

Some medications are susceptible to stomach acid, which can diminish their effectiveness or irritate the stomach lining. As a result, these are formulated as enteric-coated tablets, allowing them to pass through the stomach intact and only dissolve in the small intestine.

Certain medications, while not directly affected by stomach acid, are specifically designed for intestinal diseases, thus requiring enteric-coating to ensure they only release their active ingredients in the intestines. These medications should not be broken or chewed, as doing so can either increase side effects or inhibit their effectiveness.

Common enteric-coated medications include enteric-coated erythromycin, midecamycin tablets, and pancreatic enzyme tablets.

4. Coated Tablets

Coated medications refer to those that have a layer on the outside, which serves to protect against moisture and light, helping with preservation. This coating can also mask unpleasant odors and lessen irritation to the mucous membranes in the mouth, esophagus, and gastrointestinal tract, among other benefits. In summary, the advantages of this technique are numerous.

Given the protective coating, it is clear why these medications should not be broken before use. Damaging the coating negates its purpose, correct? The enteric-coated medications mentioned earlier are also a form of coating known as an enteric shell. Beyond enteric-coated drugs, other types include sugar-coated and film-coated medications.

Numerous coated medications exist, and it would be impractical to list them all here. You can identify them through the "characteristics" section on the medicine packaging or in the product insert.

5. Chemotherapy and Targeted Drugs

Patients should also exercise caution regarding the splitting of chemotherapy and targeted drugs. These are particularly hazardous and must be used judiciously according to medical guidelines.

In conclusion, whether a medication can be split is a decision that should be made by a healthcare professional. Additionally, prior to taking medication, always check for signs of cracking. Medications may become damaged or cracked due to improper storage or quality control issues, which carries similar risks as splitting.

Finally, a helpful fact: Some slow-release and controlled-release medications have their active ingredients absorbed while their outer "frame" is expelled whole with stool. In such cases, there is no need for concern; the medication you ingested has indeed done its job. The "frame" can simply be disregarded.