Tablet Splitting: Common Practice But Is It Realiable?

Most commonly used method for dose adjustment but what about the dose accuracy.

Throughout my journey as a hospital pharmacist I received many prescriptions that indicated split of tablets. At first I generally delivered it to patients as written by health care professions but later I researched willing to get some insight in this practice.

What is splitting of tablets?

Normally a tablet dosage form has a scorelineor a breaklineon the surface indicating that this particular tablet can be broken down before administration. Tablets can be divided with the help of tablet splitter where individual tablet is kept on a sharp blade and pressed from above resulting in two halves.

Or it can be broken down manually by hand or with an aid of kitchen knife. Tablet splitting has now become a common strategy to obtain a low dose and save medication cost. Particularly in developing countries like Nepal, this practice is more common due to unavailability of all the dose manufactured, especially in rural areas. Low drug dose is seldom produced by the pharmaceuticals and not included in hospital formularies due to difficulties in preparing minimum content. For this reason, breaking down a tablet dosage form has been widely accepted by health care professionals.

A statistical analysis on prevalence of tablet splitting revealed that it was common in case of geriatric and paediatric patients for dose adjustments and ease of swallowing. This practice also proves to be beneficial when a tapering of dose (reducing tablet strength slowly) is required especially in antipsychotics and corticosteroids.

However, subdividing a tablet may not be a recommended practice for numerous reason. Exercising this method is based on assumptions that a split tablet will result in two equal halves that will contain equal amount of drug but health care professions and consumers should both understand that a tablet dosage form is designed with active ingredient along with other excipients which completes a tablet dosage form.

When a tablet is split it might result in two unequal halves that vary in weight which directly influences content of active ingredient that directly affects clinical outcome. This is the matter of concern mainly for potent drugs with narrow therapeutic index. Studies have shown that, factors like shape and size of a tablet, medium used to split a tablet, presence and depth of score lines in a tablet and also composition of tablets directly influences the degree of accuracy in achieving two equal halves of a tablet.

In 2010 drug safety oversight board of Centre for Drug Evaluation and Research (CDER/FDA) investigatedpractice of tablet splitting but authentic guidelines were not formed to address the scoring of the tablets.Finally, in 2011, FDA introduced a draft ontablet scoring focusing on producers to provide data related to scored tablets. Later research was done to check the content uniformity and weight variation of split tablets to ensure dose accuracy.

Till date very less research has been published on this matter and breaking down a tablet is still controversial as results are completely based on individual tablet, property of active molecule responsible for pharmacological action. A study published on ‘Journal of pharmacy practice’ indicated that drugs with deep scoreline gave uniform weight of half tablets than tablets having no scoreline. Obtaining two equal halves can be greatly influenced by the technique used to break a tablet. A study published on 2017 indicates that a tablet splitter resulted in tablets with low percentage of weight loss than those broken down with a knife.

A study which focused on choice of fillers and binders for tablets that are commonly split concluded, elastic diluents such as dibasic phosphate dehydrates conferred a more appropriate behaviour for the subdivision process than plastic materials such as microcrystalline cellulose and lactose.

What to know before splitting a tablet?

Based on a guideline published by FDA in 2013 “Tablet Scoring: Nomenclature, Labeling and Data for Evaluation” associated people should know whether to split their medications or not.

If a tablet is FDA-approved to be split, this information will be printed in label insert along with scoreline indicating where to split it.
Splitting of entire supply of tablets at one time and then storing them for later use is not recommended by FDA. This is important because split tablets may be affected by factors such as heat, humidity and/or moisture content. So it is very necessary to make sure that both halves are consumed before splitting the next tablet.
Active drug content after splitting the tablet should not be below the minimum therapeutic dose.
The split tablet should be stable for a period of 90 days at controlled room temperature condition when stored in pharmacy containers.

Consumers should always consult health professionals before breaking down a tablet.

Patients, health care professionals and other associated people should be aware of problems associated with tablet splittingin advance so that therapeutic goal behind prescribing those medicines are met. Pharmaceutical manufacturers must also be responsible to deliver a well-designed tablet particularly focusing on the score line and physical characters of a tablet when they are aware about its splitting in future prior to consumption.

Companies must follow regulations for scored tablets published by USP (United States Pharmacopeia) and FDA(Food and Drug administration) and parameters should be adjusted to ease tablet splitting as well. As splitting of tablets with narrow therapeutic index can lead to adverse effects of tablet that are undeniable, all doses required should be manufactured as much as possible to avoid spitting of such tablets.

Recently a research was done on manufacturing a multi-layered tablet (Tablet with one or more active ingredient) with an inclusion of a scoreline to ensure accurate dose distribution in two halves. As per FDA guidelines tablet splitting is not recommended in modified release products as it may result in uncontrolled release pattern but still score line on such products are available in the market. Manufactures and regulatory bodies should investigate on this matter as well.