Altering dosage forms for older adults
- Selina Taylor, Beverley D Glass
- Aust Prescr 2018;41:191-3
- 3 December 2018
- DOI: 10.18773/austprescr.2018.063
Swallowing difficulties in older adults present challenges for medication management, particularly as polypharmacy is so common.
It is also important to review the patient’s swallowing difficulties and medication management regularly. The limited availability of oral liquids and other dosage forms given by alternative routes means that crushing tablets and emptying capsules is common practice.
Altering dosage forms can have adverse clinical consequences. It is important to consider whether the medicines are still necessary.
If the medicines are essential, find out if there are alternative formulations. Check guidelines and the product information before altering dosage forms.
The legal implications of altering dosage forms can be minimised by following evidence-based practice, clearly documenting the reason for altering the medicine and obtaining written consent from the patient or their carer. Review the patient’s swallowing ability and treatment regimen regularly.
Polypharmacy, dysphagia and age-related pathological changes in older adults present challenges for medication management. As many as one in five older patients has difficulty swallowing and may have problems taking tablets and capsules.1,2
The limited availability of oral liquids, patches and suppositories means that crushing tablets and emptying powder from capsules is very common, particularly in aged-care facilities and nursing homes.3-6 Multiple medicines are often crushed together and mixed with a food or a thickening agent for administration.3 Altering solid dosage forms is associated with a number of problems.
The stability and bioavailability of drugs can be significantly changed by the simple act of crushing a tablet, preparing an oral liquid from a tablet or capsule, or mixing a crushed tablet or capsule powder with food or other thickening agents.7
When faced with a patient who is unable to swallow solid dosage forms, consider the following:8
Often medication errors and unsafe medication use occur when dosage forms are altered because of limitations in health professionals’ knowledge and the lack of availability of guidelines or appropriate reference materials.6 The Society of Hospital Pharmacists of Australia has produced the Australian Don’t Rush to Crush Handbook to assist with appropriate dosage-form modification.9 (Similar information is also available as an add-on through MIMS.) The handbook recommends five primary methods of managing a medicine that cannot be swallowed whole.9 These include:
Table - Examples of drugs unsuitable for dosage-form modification and suitable alternatives9
|Proton pump inhibitors||Oral granules or dispersible form|
|Sulfasalazine EN tablets 500 mg||Sulfasalazine tablets 500 mg (plain)|
|Metformin 500 mg/1000 mg extended-release tablet||Metformin 500 mg tablet (plain)|
|Ferrous sulfate 325 mg modified-release tablet||Ferrous sulfate 150 mg/5 mL liquid|
|Paracetamol 665 mg controlled-release film-coated tablets||Paracetamol 500 mg tablets (plain or dispersible form)|
|Gliclazide 30 mg/60 mg modified-release tablet||Gliclazide 80 mg tablet (plain)|
|Dabigatran 75 mg/110 mg/150 mg capsule||No alternative formulation available – consider other anticoagulants|
Additionally, there have been significant developments in both transdermal drug delivery and orally disintegrating dosage forms (e.g. olanzapine wafers) which are easily administered to patients with swallowing difficulties.
Bioavailability represents the amount of drug that reaches the systemic circulation and elicits an effect.6 The rate and extent of drug released from the formulation may be altered by the crushing process, resulting in potential changes in the concentration–time profile.6 Crushing solid dosage forms may also enhance dissolution and increase bioavailability. For example, if controlled-release opioids are crushed, there is a risk of dose dumping and overdose.6 Alternatively, crushing may lower the dose because of drug loss during preparation and administration.9-12
Controlled-release, slow-release and extended-release products are specifically designed to deliver the drug over a prolonged period of time.6 If a controlled-release formulation is crushed, the duration of the drug’s activity is reduced and the entire quantity of the drug may be immediately released resulting in toxicity.6 Crushing enteric-coated medicines that are acid labile will damage the coating and expose the drug to the acidic stomach environment. This may have a two-fold effect of irritating the stomach lining and causing discomfort, or inactivating the drug if it is extremely susceptible to acid degradation.9
Crushed tablets and capsule contents are commonly mixed with food to assist with both drug administration and adherence. In studies of various health facilities, 23–96% of patients were given at least one medicine daily mixed into their food or beverage to mask the unpleasant taste.3,5,10 Common foods and beverages used included fruit juices, apple sauce, milk, jams, custards, yoghurt, honey, pudding and in one case sprinkled on a patient’s toast.5,6,9,13
Dissolution, which is required before a drug can be absorbed, has been investigated when solid dosage forms were crushed in orange juice, honey, jam, yoghurt and a commercial powder thickener.11,12 Although yoghurt is often used as a vehicle for mixing and administering crushed tablets, this is controversial as it may affect drug dissolution.12 The adhesive properties of honey and jam may not significantly affect dissolution, but they can be sticky in the mouth and their high sugar content can cause dental problems and affect a patient’s glycaemic control.12
Potential complexation of the drug with the food or an alteration of the pH environment (which can affect drug stability) may also alter a drug’s therapeutic effect.6 Accurate dosing is also difficult to achieve if patients do not finish their food.12 Additionally, adding medicines to food and drink may discourage patients from eating.14
Health professionals who modify formulations have both legal and clinical implications to consider (Box). Administration of any medicine that has been altered from the licensed (original) dosage form by any health professional is considered off-label use and has liability consequences.9 As modification produces neither an approved or labelled product, administration, particularly if mixed with food or a thickening agent could be seen as unlawful practice.7 In some cases dosage-form modification may be occurring without the knowledge or authorisation of the prescriber.2
Clinical implications (examples)
Increased toxicity (crushing extended-release products results in dose dumping)
Reduced efficacy (crushing enteric-coated tablets may result in the drug being destroyed by stomach acid)
Instability of the drug (pharmacokinetic changes)
Unpalatability (resulting in non-adherence)
Potential risk to healthcare workers (exposure to cytotoxic drugs)
Unintended aspiration (patient with dysphagia aspirating a medicine)
Incorrect dosage administration (loss of drug during crushing process)
Legal and professional implications (examples)
Off-label drug use (opening a capsule or crushing a tablet before administration)
Lack of consent for administration (patient may be unaware of medication provided in food)
Cross contamination (one crushing device being used for multiple patients’ medicines, placing patients at risk of adverse effects such as allergic reactions)
Potential liability may be minimised by:9
Older adults make up 20% of the population, but take 50% of all prescribed medicines. Consequently, the bioavailability, stability, safety, clinical and legal impacts of drug administration and alteration require careful consideration.
The following recommendations may be used as a guide if patients are having swallowing difficulties:
Conflicts of interest: none declared
Rural pharmacy academic, Mount Isa Centre for Rural and Remote Health, James Cook University, Queensland
Professor of Pharmacy, College of Medicine and Dentistry, James Cook University, Townsville, Queensland