Monsoon in India always arrives with a baggage of feelings. While there is no denying that the season brings much-needed relief from the scorching June heat, the fluctuating humidity affects day-to-day life in myriad ways. One aspect is the quality of medicines if they are not stored correctly.
Experts warn that improper storage may reduce the effectiveness of certain drugs even before their expiry date, making it important to pay attention to where and how medicines are kept at home.
DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.
Dr Aravinda S N, Lead Consultant, Internal Medicine, Aster RV Hospital, Bengaluru, explained that excessive moisture and heat can trigger chemical breakdown or alter the physical structure of medicines. “Tablets and capsules that absorb moisture are particularly vulnerable. They may soften, swell, become sticky or crumble. Effervescent tablets and dry powder formulations are also highly sensitive to humidity,” he said.
Why humidity and heat can reduce medicine effectiveness
He warned that heat-sensitive medicines, including insulin, vaccines, biological medicines, and some liquid formulations, require special attention and should always be stored according to the manufacturer’s instructions. On the other hand, creams and suppositories can also soften or separate when exposed to high temperatures.
One of the most common mistakes people make during the rainy season, Dr Aravnind pointed out, is storing medicines in bathrooms, where repeated exposure to steam and humidity can damage them. He stressed that keeping medicines near kitchen sinks, stoves, or windows is equally problematic because these areas experience frequent temperature and moisture fluctuations.
He also advised against removing tablets from their original blister packs or transferring them to unsealed containers, as this reduces protection from humidity. Handling medicines with wet hands or failing to close bottle caps tightly can also allow moisture to enter.
How to store insulin safely during humid weather
Dr Aravinda said refrigeration is necessary only if the product label specifically recommends it or a healthcare professional advises it. Medicines intended for room-temperature storage can be damaged by unnecessary refrigeration, which can cause condensation or freezing.
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“Refrigeration only makes sense when the product label says so or a healthcare professional gives that instruction directly. Some medicines do need controlled cold storage, usually in the range of 2°C to 8°C, but it depends entirely on the exact product,” he said.
Dr Pranav Ghody, Consultant Endocrinologist and Diabetologist at Wockhardt Hospitals, Mumbai Central, stressed that once opened, most insulin pens or vials can be stored at room temperature according to the manufacturer’s instructions, provided they are protected from direct sunlight, excessive heat, and humidity.
“Patients should inspect insulin for any changes in colour or appearance and avoid using it if it has been exposed to extreme temperatures,” Dr Ghody said.
How to check tablets, syrups, and creams for spoilage
If medicines accidentally get wet during flooding or heavy rain, he recommended discarding them immediately, particularly if they have been exposed to contaminated water. This applies to tablets, capsules, syrups, injectables, inhalers and topical medicines, even if the packaging appears intact. Wet tablets or capsules should never be dried and reused, he added.
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For people living in homes without air conditioning, Dr Aravinda recommended storing medicines in a closed cupboard or storage box in the coolest, driest part of the house. They should be kept away from bathrooms, kitchens, direct sunlight and windows, while remaining in their original packaging with containers tightly sealed.
Further, he explained that medicine bottles contain silica gel packets or desiccant canisters designed to absorb excess moisture. “It must not be swallowed, ever. People should also look over their medicines more often during rainy, humid weather, basically. If tablets get unusually soft, swollen, cracked, crumbly, sticky, or they even change colour, that can point to moisture exposure,” he said.
“Capsules might also end up stuck together, look warped, or seem softer than normal. For syrups, keep an eye out for stuff like unexpected cloudiness, separation, bits floating around, colour shifts or an odd odour before using it. With creams, you might see separation; they can become overly watery, or there can be changes in texture or smell,” he added.
For syrups, he explained, cloudiness, separation, floating particles, unusual odour or colour changes are warning signs. Creams and ointments that develop separation, become unusually runny, change colour or smell different should be checked by a pharmacist or doctor before use.
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“With creams, you might see separation; they can become overly watery, or there can be changes in texture or smell,” Dr Aravinda said.
DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.