Leftover medicine: Now what?

An antibiotic suspension is prescribed for a young child with acute otitis media. After five days of treatment with the antibiotic, the child appears to the mother to have fully recovered, and the remaining five-day supply is not given. One-half of the bottle is left over – should it be poured down the sink, flushed down the toilet or, as many families may do, should it be kept in the refrigerator for the next infection? If asked, what recommendation would you give this mother?

Disposal of medication has recently been discussed in the lay and medical literature, and the federal government issued recommendations several years ago on medication disposal.

The potential for pharmaceutical agents and chemicals to eventually find their way into public water supplies, such as rivers and streams, including drinking water, has additionally raised new concerns. Several studies have found very small amounts of various pharmaceutical agents in public water supplies, including antibiotics and hormonal compounds. Newer detection technologies have allowed smaller amounts of various chemicals to be identified. Many believe that pharmaceutical agents found in public water are mostly delivered into the environment by normal waste disposal mechanisms. Medications excreted from the human body renally or through solid waste enter disposal treatment plants and eventually can be found in the environment. The environmental and clinical implications of exposures to very small amounts of various pharmaceutical agents, regardless of the mechanism to enter the environment, are not known. Environmental scientists and clinicians are beginning to consider these issues.

Storage of medication

Medication products stored inappropriately are more likely to lose potency, and thus proper storage can be important. Most medications do not “go bad,” when stored improperly or for a long period. However, medications lose potency over time. This can have important clinical implications if a sub-potent medication is taken and relied upon for therapeutic effect. The classic example of a medication chemically degrading to a potentially toxic substance is tetracycline. Older reports demonstrated that use of outdated tetracycline resulted in renal toxicity or Fanconi-like syndrome. Newer tetracycline products, however, are more stable and are less likely to cause similar toxicities.

If one considers the ideal conditions for proper storage of medication, then the actual storage conditions used by many families are far from optimal. Where are medications often stored in the home? Quite often they are stored in the “medicine cabinet,” which is in the bathroom (with much humidity). Moisture is more likely to cause a solid medication product to lose potency. Most medication products should be stored in a cool, dry and dark place, such as a dresser drawer or cabinet.

Expiration dates

All medication products are labeled with an expiration date that is determined by the manufacturer. This date is assigned after stability tests are conducted, and is usually two to three years after manufacture. After the expiration date as passed, the manufacturer cannot guarantee labeled potency. Proper storage of the medication product is important, and if it is not stored under optimal conditions, the product is likely to lose potency sooner than the labeled expiration date. When a medication product is dispensed from a pharmacy, another date indicating when the medication should no longer be used is placed on the label. This date, often referred to as a “beyond-use” date, typically is one year from the dispensing date, or the manufacturer’s expiration date (whichever is earlier). This earlier date is used, as once the medication has left the pharmacy with the patient, storage conditions often change, affecting medication potency. Antibiotic suspensions — commonly used in young children — are typically prepared by reconstitution from a powder. These products are unstable and usually have expiration dates of 10 to 14 days once reconstituted.

Proper disposal of medication

In 2007, several federal agencies jointly released guidelines on proper medication disposal.

Most medication products should be disposed of in normal trash containers. The medication should be taken out of the original container and mixed with some type of unpalatable substance, such as coffee grounds or kitty litter, to prevent young children, pets, or others from being potentially exposed to the product.

Unused or expired antibiotic suspensions can be poured into a sealable plastic bag and should not be flushed into a sink or toilet. Some communities have “pharmaceutical take-back” programs, in which expired or unneeded medications can be taken to a safe, central site in a community and safely disposed.

Only a small number of medications should be flushed into a toilet or sink (Table). Controlled substances, such as opioid products (eg, morphine), should generally be disposed of into a sink or toilet and not thrown into a normal trash container, where they may be more easily retrieved. These products have a narrow therapeutic index, and exposure to only small mounts may be fatal to young children. Controlled substances, especially those available as unique dosage forms, often include specific disposal instructions in their labeling and printed patient information.

Proper medication disposal is especially important for the pediatric population, as young children can easily be inadvertently exposed to medications. Case reports have been published of young children who found and fatally ingested discarded medications, such as fentanyl patches. Published data demonstrate that of children can access medication products despite child-resistant containers.

Conclusions

Proper medication disposal may not often be given conscious thought, but unintentional exposure to medications by young children can result in fatal consequences. How to dispose of unneeded or expired medications should be discussed with parents and caregivers. Most medications should not be simply flushed down a toilet or sink, although this an appropriate means of disposal for some products. Information on proper disposal for specific medications is available online from the FDA and should be shared with patients and their caregivers.

Edward A. Bell, PharmD, is a Professor of Clinical Sciences at Drake University College of Pharmacy, Blank Children’s Hospital and Clinics in Des Moines, Iowa.

For more information:

• Food and Drug Administration. Medication disposal: questions and answers. http://www.fda.gov/Drugs/ResourcesForYou/Consumers/BuyingUsingMedicineSafely/EnsuringSafeUseofMedicine/SafeDisposal ofMedicines/ucm186188.htm
• McFee RB. Hang up your pocketbook – an easy intervention for the granny syndrome: grandparents as a risk factor in unintentional pediatric exposures to pharmaceuticals. J Amer Osteopathic Association. 2006;106:405-11.