Splitting Tablets

• Reasons to split medication
• Problems associated with splitting medication
  • Formulation factors
    • Therapeutic window
    • Coated and controlled release tablets
    • Scoring
    • Stability
  • Patient factors
    • Dexterity and strength
    • Compliance
• Deciding to split medication

Breaking tablets into smaller portions (usually halves) has long been considered an acceptable way of obtaining a particular dose of medication.

Reasons to split medication

There are a number of reasons why you may want to cut your medication:

• You need a particular strength of medication, and a tablet of the required strength is not available.
• You are on a flexible dosing regimen, and need to increase or decrease the dose to obtain the best effect with the least side effects.
• Some elderly patients or children may not find the liquid formulation suitable, or the liquid formulations of the medication are not covered by the Pharmaceutical Benefits Scheme (PBS).

Splitting medications may also be more cost effective, and if you are from a low economical background you may find it an attractive option.

Problems associated with splitting medication

There may be a number of problems with splitting your medication, both in terms of patient factors and formulation factors.

Formulation factors

Therapeutic window

An uneven break will give a dosage different to the the one desired. Tablets which are unevenly broken can have significant implications on patients, especially with those medications that have a narrow therapeutic window (e.g. warfarin).  

Coated and controlled release tablets

The way that tablets dissolve and are absorbed into the body changes when they are split, especially coated and controlled release tablets. Changing the way a medication is absorbed (e.g. how long it takes for the medication to enter the body, how strong it is at any one time, how long it stays in the body) can decrease its positive effects or increase its negative effects.

Extended release medications are designed to have an effect over a long period of time. Some extended release medications can be split without affecting the designed release profile (e.g. isosorbide mononitrate), but other extended release medications cannot be split (e.g. tramadol).

Some drugs are coated in another substance to hide the taste of the drug. By splitting the tablet and thus breaking the coating, the drug’s taste may be exposed.

Antineoplastic agents (e.g. chemotherapy drugs or cytotoxic drugs) are potentially harmful. Healthy individuals should have as little contact with them as possible, either by skin contact or air-borne particles. Breaking the coating of medications containing antineoplastic agents may compromise safety. Therefore, tablets containing antineoplastics should not be split, crushed or broken.

Scoring

Tablets are usually scored when it is acceptable to cut them, leaving a groove in the surface of the tablet along which a break may form. However, not all tablets are easy to break even though they are scored. The tablet’s size and shape, and the type of scoring, will determine the accuracy of the dose obtained when the tablet is cut.

It is important to note that not all tablets that are scored are suitable for splitting. The immunosuppressant azathioprine is cytotoxic, yet the tablets are scored. These are not suitable for splitting. Before splitting any of your medications, talk to your health care professional to find out if they are suitable to be split.

Stability

The stability of the tablet when it is cut is also an important factor to consider. The cut surface of some medications may be sensitive to light, heat or air. This is of particular concern when a medication is separated into individual dose administration aids.

Do not use any medication that has changed colour, consistency or shape. These may be ineffective or have negative side effects.

Patient factors

Dexterity and strength

Tablets are usually cut by using a finger along the score lines, or by using a commercially available tablet cutter. In order to cut properly and as accurately as possible, you need a lot of dexterity. Otherwise, the tablet is unevenly divided, or a lot of waste is produced as tablets break into unusable portions.

If you suffer from arthritis or Parkinson’s disease, cutting tablets may be difficult due to impaired manual dexterity or reduced grip strength. Alzeimer’s patients may also face problems due to decreased cognitive function, and may not remember how to split a tablet properly.

Splitting medication will be more difficult for patients on multiple drugs, or if there is more than one tablet to split.

Compliance

You may decide it is easier to skip or double doses, rather than to split a tablet and keep the other half for later. This may decrease the treatment’s effectiveness, or increase the side effects you experience. It is important to follow your health care professional’s instructions regarding any medication you take. 

Deciding to split medication

The cost effectiveness of cutting a tablet may be outweighed by the potential detrimental effects on your health, drug wastage, and the quality of the medicine. Your doctor will decide whether it is a suitable option for you and your medications. It is important that your doctor educates you on splitting tablets so that you make the best use of your medication.

References

1. Marriott JL, Nation RL. Splitting tablets. Aust Prescr. 2002; 25(6): 133-5.
2. Vivian JC. Splitting hairs and pills. U.S. Pharmacist. 2005; 30(3): 68-78.
3. Mandal TK. Effect of tablet integrity on the dissolution rate of sustained-release preparations. J Clin Pharm Ther. 1996; 21: 155-7.
4. Atkin PA, Finnegan TP, Ogle SJ, Shenfield GM. Functional ability of patients to manage medication packaging: A survey of geriatric inpatients. Ageing. 1994; 23: 113-6.
5. Marriott JL, Nation RL, in: Letters to the editor: Splitting tablets. Aust Prescr. 2003; 26: 27-9.
6. MIMS Online. Imuran [online]. 18 October 2006 [cited 10 July 2008]. Available from URL: http://mims.hcn.et.au