Flexible dosage
By dividing, the fixed dose of tablets can be changed, which increases flexibility. This is because a dose reduction may be necessary for children, for patients with renal insufficiency, for drug interactions, or for altered drug metabolism. Tablets are also divided for economic reasons. For example, the duration of therapy may be doubled if the dose is halved. If the tablets with the higher dose are less expensive, healthcare costs can be reduced. Sharing is also important for some medications, such as antidepressants or antiepileptics, when setting the dose at the beginning of therapy. It is started with a low dose that is slowly increased. The reverse is also true when discontinuing the drug, so that no withdrawal symptoms occur. In addition, higher doses can be achieved (e.g. 50 mg + 25 mg = 75 mg). Finally, it can make swallowing easier by administering two smaller halves.
Fracture grooves and fracture notches
Divisible tablets often have a break groove or break notch. Typically, they are divisible once, resulting in two halves, each with half the dose. Drugs exist with two break grooves, which can be broken into quarters (X) or thirds ( / / ). A special feature is the so-called decorative break groove. It is present only for decorative reasons (!) This fact is unknown to most patients and must be explained by the specialists. And the divisibility of some dosage forms is only intended to facilitate swallowing – not to halve the amount of active ingredient. The presence of a breaking groove or notch is not a necessary condition for divisibility. It does, however, lead to better results.
Which tablets are divisible and which are not?
Tablets with a special galenic, such as sustained-release or enteric-coated tablets or coated and bilayer tablets, are usually not divisible because the special structure is lost. In the case of film-coated tablets, the protective and final coating is removed along the breaking point. As a result, an unpleasant taste of the ingredients may be perceived. Caution: Medications with teratogenic, cytotoxic, immunosuppressive, mutagenic, photosensitive, low-dose, or irritating active ingredients should not be shared by patients. It is also not recommended for dragées and drugs with a narrow therapeutic range.
Divisibility information
Where can information on divisibility be found? Patients should contact their pharmacy or physician. Professionals can access the following sources of information:
- Drug information leaflet
- Pharmacy or practice information system
- Product brochures of the companies
- Verbal or written information from the companies
- Subject area on the website of the companies
- Compilations, for example, of associations, interest groups or hospital pharmacies.
The appearance of the tablet can give an indication, but it does not allow a final assessment.
Problems with sharing
Dividing can cause problems and is also critically discussed in the literature. Two unequal halves may result with a corresponding dose variation (up to 20%). Tablets may crumble and pieces may be lost. Dividing can be especially difficult for elderly people, patients with a disability or a disease (e.g. rheumatoid arthritis, Parkinson’s disease), because it requires some manual dexterity. During storage, the halves may absorb water, fragment further, and the active ingredients and excipients may be degraded by the oxygen or light. This can affect pharmacokinetics and efficacy. It is known that many patients, caregivers or relatives share tablets in stock. The medications can become contaminated if sanitary conditions are inadequate. Finally, shared tablets can pose a hazard. Possible solutions:
- Use a tablet divider.
- Have a relative, caregiver or pharmacy share the tablets.
- Share tablets only before use. Do not stockpile.
- Wear gloves, use disinfectant and a suitable pad.
- Avoid unnecessary sharing, for example, for reasons of cost or availability.
Small dose variations usually do not matter for clinical efficacy. However, the smaller and more non-uniform the tablet and the smaller the dose, the greater the differences. Therefore, halving is not recommended for low doses and a small therapeutic range (eg, digoxin, levothyroxine).
Summary
- Only tablets for which it has been proven to be approved may be divided.
- Sharing tablets should be avoided unless absolutely necessary.
- Higher accuracy can be achieved with a tablet divider.
- Elderly or ill patients may lack the necessary manual dexterity.
- Pregnant women should not share tablets.
- Small tablets with a low dose and narrow therapeutic range and teratogenic, cytotoxic, immunosuppressive, mutagenic, photosensitive or irritant drugs should not be divided in half.
