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- DRUG STABILITY
- Drug Storage
- DRUG-RELATED SIDE EFFECTS AND ADVERSE REACTIONS
- PHARMACY SERVICE, HOSPITAL
- Education, Pharmacy, Continuing
The stability of medications is crucial for their effectiveness and safety throughout their shelf life. Pharmacists play a key role in storing medications at the right temperatures to maintain their stability. However, once medications are dispensed to patients, ensuring optimal storage becomes challenging.
A notable discrepancy exists between the controlled conditions in pharmacies and the variable conditions in patients’ homes. While pharmacists adhere to strict guidelines, patients may not consistently maintain recommended storage temperatures due to daily and seasonal fluctuations.1 Short-term temperature excursions may not significantly affect medication stability, depending on the drug and the extent of the deviation. Many medications can tolerate brief temperature changes without major degradation. However, prolonged exposure to temperatures outside the recommended range can reduce efficacy or pose safety risks.2 3
This past summer, our hospital experienced a blackout of the centralised air conditioning due to a fire, causing temperatures on various floors to rise above 25°C within hours. Despite the emergency plan, which maintained medications between 15–25°C, a data logger recorded a brief temperature increase of 0.6°C and 0.3°C above 25°C lasting up to 1 hour 10 min. This led us to quarantine the affected medications and consult pharmaceutical companies. One company recommended the thermal destruction of their medication despite the brief temperature deviation.
This incident raises concerns about whether medications at home are stored under optimal conditions. It is unlikely that patients can consistently keep medications below 25°C, exposing them to out-of-range temperatures for extended periods.
Most patients lack the resources or awareness needed to maintain ideal storage conditions. If medications are not as stable under these circumstances as reported by manufacturers, patients could face risks from ineffective or unsafe drugs. Proper storage is vital for maintaining medication effectiveness and preventing potential toxic exposures.4
The common storage locations in homes include bedside drawers, kitchen cabinets and bedroom nightstands. These environments can expose medications to fluctuating temperatures, light and humidity, compromising their stability.5
Inadequate storage can also pose a safety risk, especially in households with children or pets.6 7
Patients need to be educated on the importance of storing medications in cool, dry places, away from direct sunlight and heat sources.6 7
Evidence shows that improper storage can significantly affect medication stability and efficacy. Exceeding temperature limits, particularly during summer, can reduce the potency of heat-sensitive drugs like insulin and certain biologics.7 8
β-lactam antibiotics, for example, commonly used in hospital settings via slow continuous infusion, are vulnerable to degradation when exposed to temperature fluctuations in solution, reducing their clinical efficacy. A systematic review of stability data for selected antibiotics used in outpatient parenteral antimicrobial therapy shows that not all antibiotics have been tested for stability at temperatures above 25°C.9 This highlights a critical gap in managing clinical risks, as inappropriate storage conditions could lead to pharmacological inefficacy or adverse reactions.
Similarly, diluted solutions of low molecular weight heparins, such as enoxaparin, lack stability data for exposures above 26°C if extended beyond 2 months.10 These drugs, widely dispensed in pre-filled syringes, are often stored in environments where temperatures are not consistently monitored. Additionally, the transport of these drugs by patients frequently exposes them to temperatures exceeding the recommended storage conditions, which can reach 35–40°C during the summer months.10 Lorazepam, used in the acute treatment of status epilepticus, can degrade by 10% within weeks if stored at room temperature or in ambulances, where high temperatures accelerate molecular rearrangement into a less polar carboxaldehyde derivative. Unfortunately, the safety and efficacy of this degradation product remain unknown.11
Other thermally sensitive drugs, such as atropine and naloxone, also face stability concerns. A study found that exposure to high temperatures for just a week can trigger significant degradation processes.12 For atropine, this results in hydrolysis, reducing drug concentration and causing it to disappear entirely by the fourth week of exposure. Naloxone is also sensitive to high temperatures, which catalyse degradation reactions such as the dehydration of tertiary alcohol and the hydrolysis of the allylic group. Although the degradation effect is less pronounced compared with other drugs, it still represents a significant risk for patients. The thermal instability of naloxone at temperatures commonly reached in hot climates, especially during the summer, is concerning given the increasing frequency of opioid abuse among young people, justifying further research.
Thermal instability is not limited to drugs in solution but can also affect solid forms like powders, tablets, or capsules.13 14 A systematic review and meta-analysis found that improper storage is common, with a medicine storage rate of 77% and a wastage rate of 15%. Factors such as income, education and chronic illness influence storage practices. Effective legislation, community programmes and patient education are necessary to address these issues.15
Healthcare providers must educate patients on proper storage and guide them in managing medications that have been exposed to inappropriate temperatures. Patients should be encouraged to store medications under recommended conditions and consult healthcare professionals if they have concerns.16–18
With increasing global temperatures and changing climate patterns, longer and hotter summers pose a growing threat to medication stability. Regulatory agencies must work with the European Medicines Agency to mandate detailed temperature stress testing in medication data sheets. This would provide healthcare professionals and patients with the information they need to take appropriate precautions.
In conclusion, while pharmacists ensure stringent storage conditions, patients face significant challenges in maintaining these conditions at home.5 7 15 Effective communication, education and regulatory guidelines are essential to ensure that medications remain safe and effective throughout their use.
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Footnotes
Contributors AP and SDM wrote the paper, reviewed, and edited it. AP (guarantor) validated the final draft of the paper.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; internally peer reviewed.