Seasonal changes don’t just affect what people wear or how they feel—they can also have important, often overlooked effects on medication safety. For residents in long-term care (LTC), these effects can be amplified. Here’s how seasonal shifts can influence medication stability, dosing, and overall safety—and what LTC pharmacies and care facilities can do to stay ahead.

How Seasons Affect Medication Safety

1. Heat, Sunlight & High Temperatures (Summer)

• Medication stability and degradation: Many medications are sensitive to heat and sunlight. Excessive exposure can degrade active ingredients, reducing efficacy or even leading to unsafe byproducts. Regulatory guidelines generally require storage at ~25°C (77°F) or lower for many drugs. Excursions above that, especially prolonged ones, risk loss of potency. SPS - Specialist Pharmacy Service+3PMC+3helmerinc.com+3

• Storage guidelines: The United States Pharmacopeia (USP) Chapter 1079 states that "Room Temperature Storage" is 20°C–25°C, with permitted excursions of 15°C–30°C for many medications. helmerinc.com

• Risk to temperature-sensitive medications: Drugs like insulin, certain biologics, and some antibiotics are particularly sensitive. If they become too warm, they may degrade or lose stability. varcode.com+2PMC+2

• Increased risk of dehydration: In hot weather, dehydration is more likely, especially among older adults. Dehydration can change how drugs are absorbed, distributed, metabolized, and excreted—impacting concentrations of medications in the body. MDPI+3MDPI+3bremorx.com+3

2. Cold Temperatures (Winter & Early Spring)

• Freezing or near-freezing exposure: Some medications must be protected from cold; freezing can cause irreversible damage (e.g., creams, suspensions, some injectables). While less common than heat damage, cold exposure is still a risk if storage or transport isn’t properly managed. (Although specific studies in LTC settings are fewer, the general pharmaceutical stability literature supports avoiding freezing unless specified.) varcode.com+1

• Physiological changes: Cold can affect circulation and metabolism. For example, vasoconstriction in cold may impact drugs that rely on peripheral blood flow. Also, respiratory illnesses increase, which may interact with or complicate existing regimens (e.g., inhalers, bronchodilators). While detailed research is less abundant here, clinical experience and pharmacology suggest these are meaningful effects.

3. Seasonal Illnesses, Allergies, and Their Interactions

• Allergy season (spring/fall): Increased use of antihistamines, decongestants, or nasal steroids adds complexity. These may interact with medications for blood pressure, heart conditions, or cognitive impairments.

• Flu and respiratory infections: When LTC residents contract seasonal viruses, their medication regimens often change (e.g., adding antivirals or antibiotics). There is risk of interactions or increased burden on organs (e.g., kidney, liver), particularly if hydration is suboptimal.

• Vaccination periods: Adding vaccines to existing medication schedules requires review to ensure there are no contraindications or timing issues, especially for immunocompromised residents.

Why Older Adults in LTC Are Especially Vulnerable

• Reduced physiological reserves: As people age, their kidney and liver function often decline, and their ability to regulate body temperature is less efficient. Thus, the effects of dehydration or temperature stress are more pronounced. MDPI+2MDPI+2

• Multiple medications (polypharmacy): Many LTC residents take numerous medications; this increases the chances of interactions and complicates dosage adjustments when seasonal conditions shift.

• Mobility, cognition, and hydration challenges: Physical limitations, cognitive impairment, or reduced thirst sensation can make maintaining proper hydration more difficult. Studies show a high prevalence of dehydration among older adults in LTC settings, which correlates with worse health outcomes including rehospitalization. jnursinghomeresearch.com+2MDPI+2

• Environmental controls in LTC facilities may vary; not all areas may maintain optimal temperature/humidity.

Best Practices LTC Pharmacies & Facilities Can Implement

To mitigate these seasonal risks, here are proactive steps your pharmacy and LTC facility can take:

Sources & Evidence

To support these recommendations, here are key sources:

1. USP Chapter 1079 Good Storage and Shipping Practices — outlines storage ranges for “room temperature” (20–25°C), allowed excursions (15–30°C), refrigeration (2–8°C), etc. helmerinc.com

2. Crichton et al., Exposure of medicines to high temperatures in storage or in transit — discusses how exceeding standard storage temps reduces efficacy or causes drug degradation. PMC

3. Masot et al., Trends in Dehydration in Older People (2025) — shows dehydration is common in LTC residents and associated with increased mortality and morbidity. MDPI

4. Lacey et al., A multidisciplinary consensus on dehydration — elderly are particularly at risk due to physiological changes, medication use, etc. Taylor & Francis Online

5. Studies on medication storage in households and ambient storage guidelines — showing that many medications require precise temperature control, and that common storage practices may expose meds to heat, light, or moisture. SPS - Specialist Pharmacy Service+3PMC+3Baystate Health+3

6. Research on hydration in LTC residents (e.g. “Hydration Status of Long Term Care Residents Rehospitalized …” & “Hydration Strategies …”) — showing low hydration is often unrecognized and leads to worse outcomes. jnursinghomeresearch.com+2MDPI+2