How to Store Medicines in Summer So They Don't Lose Their Effectiveness

Picture this situation. A scorching July day. You leave your car in the car park outside a shopping centre, with a handbag inside, and in it a standard kit: painkiller tablets, an allergy medicine, a nasal spray. You come back two hours later. Inside the car it's like an oven – the steering wheel scalds your hands, and the temperature inside has comfortably passed 50 degrees.

You take a tablet in the evening and nothing happens – the medicine doesn't work the way it usually does. Or it works, but you have no idea that the active ingredient inside has already partly broken down. Because a heat-damaged medicine usually looks exactly the same as a healthy one. And that is the most insidious thing about it.

In summer, medicines need a different kind of care than in the cool months. High temperatures, sunlight and humidity can quietly reduce their effectiveness or even change their properties. Today we'll go through this in concrete terms: what happens to medicines in the heat, what you absolutely must not do, what needs the fridge, how to carry medicines while travelling, and how to recognise that a medicine should be thrown away.

What heat does to medicines

A medicine is not just the active ingredient – it is a precisely designed whole: the active substance, the excipients, the coating, the carrier. High temperatures can throw this system out of balance in several ways.

Loss of effectiveness

The most common consequence of overheating is a drop in the medicine's potency. The active ingredient breaks down, and its actual content in the tablet or syrup falls below the stated value. You take "the full dose", but you are in fact delivering less to your body – and the medicine works more weakly, or not at all.

Breakdown of the active ingredient

Under the influence of heat, some medicines not only lose potency but break down into degradation products. In most cases this simply means an ineffective medicine, but it is another reason not to use an overheated medicine "just in case".

Change in consistency and appearance

Heat is most clearly visible in medicines with a "soft" dosage form. Suppositories can melt and set again in a deformed shape. Ointments and creams can separate – the oil splits away from the water phase. Tablets are sometimes discoloured, crumble or stick together. Gelatin capsules soften and stick to one another.

Humidity – the silent ally of heat

In summer the problem is not only temperature, but also humidity. Effervescent tablets, some film-coated tablets and powders are sensitive to moisture – they can become damp, clump together and lose their properties. That is why the bathroom, convenient as it is, is one of the worst places for the medicine cabinet.

The most important point: a medicine spoiled by heat most often does not change its appearance enough for you to notice it straight away. A tablet can look normal and yet already be weakened. That is why it is crucial not to allow overheating in the first place.

What not to do with medicines in summer

Most summer mistakes come down to a few recurring situations. If you avoid them, you are already largely safe.

Don't keep medicines in a baking-hot car

This is the absolute number one. In a parked car on a sunny day, the temperature inside can pass 50, even 60 degrees within a short time – dramatically more than outside. The glove compartment by the dashboard and the shelf under the rear window are the hottest spots in the car. Don't leave medicines there – not even for a moment "because I'll be right back", and certainly not for the whole day.

Don't place medicines on a windowsill in the sun

Direct sunlight is a double threat: it heats the medicine and exposes the active ingredient to light. Many medicines are light-sensitive – which is why they come in opaque blisters, dark bottles or tubes. Keeping them on a windowsill or in a sunny spot undoes that protection.

Don't store medicines in a humid bathroom

The bathroom seems logical – medicines "to hand" by the basin. But steam from the shower and fluctuating humidity affect many preparations badly. A better place is a cool, dry cupboard in the bedroom or hallway, away from heat sources.

Don't leave medicines in a backpack at the beach

A backpack or bag lying on the sand in full sun heats up very strongly. If you take medicines to the beach, keep them in the shade, ideally in an insulated bag, and don't place them directly on the hot sand.

Don't keep medicines near heat sources at home

Even in a flat there are warmer places: above the cooker, beside the oven, right by the balcony window, on top of the fridge (the top can be warm from the motor). Keep the medicine cabinet away from such points.

What needs the fridge

Some medicines must be stored in the cold – usually at a temperature of roughly 2 to 8 degrees. In summer this is especially important, because outside the fridge they overheat quickly.

Among the things that need to be stored in the fridge are:

• Insulin – supplies are kept in the fridge; the cartridge currently in use can usually be stored for a defined period at room temperature, but it must not be overheated or frozen.
• Some eye drops – a number of ophthalmic preparations, especially after opening, require cooling.
• Suppositories – they melt in the heat, so in summer it is often safer to keep them in the fridge.
• Some antibiotics in suspension form – after preparation (dissolving), many of them are stored in the fridge for a limited time.
• Selected biological medicines, vaccines, some injectable preparations – they have strictly defined cooling requirements.

Always check the patient leaflet and the label – they tell you how to store a given preparation. If in doubt, ask your pharmacist. And remember an important rule: "fridge" does not mean "freezer". Most medicines must not be frozen – frost damages them just as much as heat. Keep them on a fridge shelf, not against the freezer wall and not in the door, where the temperature fluctuates strongly.

Travelling with medicines in summer

A holiday trip is the moment when storing medicines is hardest – and when a mistake is easiest to make.

Cool bags and cooling packs

If you are carrying heat-sensitive medicines (insulin, some drops, suppositories), get yourself a small insulated bag and cooling packs. Important: the medicine should not be in direct contact with a frozen pack – wrap it so as to cool it, but not freeze it. There are also special cooling pouches and cases designed for medicines – a convenient solution for longer trips.

Travelling by car

In the car, plan how you carry medicines sensibly. Don't leave them in a parked, baking-hot car. While driving, keep them in the air-conditioned cabin, in the shade, ideally in a cool bag – not on the shelf under the rear window and not in the boot, which can heat up strongly.

Travelling by plane

Here the rule is clear-cut: we carry medicines in hand luggage, not in the hold. The luggage hold is not as comfortably regulated as the cabin, and luggage can be exposed to low temperatures – medicines can become over-chilled, or even freeze. In hand luggage you have control over them and access if needed. Always keep medicines you take regularly on you, ideally in their original packaging with the leaflets. When travelling abroad with prescription medicines, it is worth also having a doctor's certificate or a copy of the prescription – particularly for injectable medicines.

A plan for arriving at your destination

Once you arrive at the hotel or accommodation, decide straight away where to keep your medicines. If one of them needs the fridge and there is none in the room, ask for it to be stored at reception or choose accommodation with a fridge. For the rest of the medicines, provide a cool, dry, shaded place – not the windowsill and not a heated shelf.

How to recognise a heat-damaged medicine

Although an overheated medicine often looks normal, there are signals that clearly say: do not use this.

Throw away, or consult your pharmacist about, a medicine when you notice:

• A change in colour – tablets that are discoloured, blotchy, darker or lighter than usual.
• A change in smell – a new, unusual, sharp or simply different smell from the usual one.
• Melted or deformed suppositories – if a suppository has melted and set in a different shape, it is not fit for use.
• Separated ointments and creams – visible separation of oil from water, lumps, a change in consistency.
• Stuck-together, crumbled tablets or fused capsules – a sign of the action of heat or moisture.
• Cloudiness or sediment in liquids – syrups and drops that were clear and have become cloudy or have a strange sediment.
• A damaged, "swollen" blister or effervescent tablets that have become damp.

When you have any doubts at all – don't take the risk. It is better to consult a preparation with a pharmacist or throw it away than to take a medicine that won't work the way it should. Especially with medicines taken regularly and with life-saving medicines, a functional active ingredient is absolutely crucial.

The general rule for storing medicines

If you are to remember a single sentence, let it be this: store most medicines below 25 degrees, in a dry and dark place, in their original packaging, out of the reach of children.

In practice this means:

• A cool, dry cupboard – ideally in the bedroom or hallway, not in the bathroom and not in the kitchen near heat sources.
• Away from direct sunlight and windowsills that heat up.
• The original packaging with the leaflet – that is where the information on the storage method and the expiry date is.
• Medicines that need the cold – on a fridge shelf, never in the freezer.
• Regular review of the medicine cabinet – check the expiry dates and the appearance of medicines, especially after the hot season.

The patient leaflet, however, always takes priority. The manufacturer defines the exact conditions for a specific preparation – if it says "store in a fridge" or "protect from light", take that literally.

Frequently asked questions

Is a medicine that has been lying in a hot car fit for use?

If a medicine was exposed to high temperatures for a longer time, it is better not to use it – even if it looks normal. Overheating can reduce effectiveness without visible changes. Consult the matter with a pharmacist; with life-saving and regularly taken medicines, don't take the risk.

Can all medicines be kept in the fridge?

No. Keep only those medicines in the fridge whose leaflet requires it. Many preparations feel best at room temperature below 25 degrees, and the cold of the fridge can change their properties. Never freeze medicines.

How do you carry insulin in summer?

Store your insulin supply in the fridge, and while travelling in an insulated bag or cooling case – so that it is neither overheated nor frozen. Don't leave insulin in a baking-hot car or in the sun. You will find the detailed storage rules in the leaflet and from your pharmacist.

The suppositories melted in the heat – what should I do?

A suppository that has melted and set again in a deformed shape is not fit for use. In summer it is often safer to store suppositories in the fridge. If you have doubts about a specific preparation, ask your pharmacist.

Can I carry medicines in checked luggage on a plane?

Better not. Carry medicines in hand luggage – in the luggage hold the conditions are less comfortable, and medicines can become over-chilled or freeze. In hand luggage you have control over them and access if needed.

Summary – what is worth remembering?

✅ Heat destroys medicines quietly – an overheated medicine often looks normal but works more weakly or not at all.

✅ Never leave medicines in a baking-hot car – this is the most common and most dangerous summer mistake.

✅ Avoid the sun, windowsills, the humid bathroom and the backpack at the beach – these are bad places for medicines.

✅ Insulin, some eye drops, suppositories, some antibiotics in suspension need the fridge – but never the freezer.

✅ While travelling, carry medicines in hand luggage, not in the plane's hold, ideally in a cool bag.

✅ A change in colour or smell, melting suppositories or ointments – this is a sign that the medicine is to be thrown away.

✅ The general rule – most medicines below 25 degrees, in a dry and dark place; always check the leaflet.

Disclaimer

This information is educational in nature and does not replace a consultation with a doctor or pharmacist. The way each medicine should be stored is defined by its leaflet and label – always familiarise yourself with them. If you have doubts about whether a medicine exposed to high temperatures is fit for use, consult this with a pharmacist, and do not stop medicines you take regularly on your own without talking to a doctor.

A medicine is an investment in health – but only when it retains its full effectiveness. A single hot afternoon in the car park can waste that investment. In summer, give your medicines coolness, shade and a dry place, and they will repay you with the effect you are counting on.

And when you are restocking your home medicine cabinet or putting together a holiday kit – a cool bag, suppositories, drops, medicines for the journey – drop everything into a single basket and compare it on CheaperForDrug. We check the prices of the whole basket across 100+ pharmacies at once, because real savings are born of comparing the entire shopping list, not a single pack. Look after your medicines wisely – and your budget too.