Red Flags to Watch for When Taking Antimalarial Medicine

Antimalarial medicine plays an important role in protecting people who are travelling to areas where malaria is common. These medications work by reducing the chances of getting sick from mosquito bites that carry the parasite. They are usually taken before, during and after travel to help the body build resistance and stay protected.

But while these medicines are effective, they can also come with some unwanted effects. Most side effects tend to be mild and pass quickly, but some may need medical attention. Knowing how to tell the difference can make a big difference in your safety. If you're taking antimalarials or plan to, it's worth understanding what to look out for so you're not caught off guard.

Common Side Effects vs. Serious Complications

Not all reactions to antimalarials are cause for concern. Like many medications, they often bring on mild symptoms that wear off as your body adjusts. But some people may react more strongly or develop symptoms that are more than just annoying. Knowing when to worry and when to wait it out is the first step in looking after your health while on this type of treatment.

Here are some of the more common side effects that many people experience:

- Nausea or an upset stomach, especially if the tablets aren't taken with food

- Feeling dizzy or lightheaded from time to time

- Headaches that are usually mild and manageable

- Trouble sleeping or vivid dreams

- Slight taste changes in the mouth

These issues don’t always mean the medicine isn’t working for you, but it’s wise to keep an eye on how long they last and if they start to get worse. On the other hand, if you start to notice symptoms that feel more severe or unexpected, that’s when it becomes important to act quickly.

Some red flags include:

- Irregular heartbeat or chest pain

- Shortness of breath that isn’t caused by activity

- Ongoing vomiting or diarrhoea that leads to dehydration

- Mood changes that interfere with daily life

- Skin rashes that spread or become painful

Mild symptoms usually pass in the first few days, but anything that gets worse or doesn’t go away should be checked by a healthcare provider. One traveller shared how they kept brushing off stomach pains while abroad, only to discover it was a poor reaction to their antimalarial when they got home. Don’t let symptoms build. It’s much easier to fix the problem early than to deal with it later after it's caused other issues.

Recognising Allergic Reactions

An allergic reaction to medication isn’t something most people expect, but it does happen. The severity can vary. Sometimes it’s subtle and can be mistaken for a common side effect, while other times, it becomes clear something is wrong.

Some signs of a possible allergic response include:

- Raised, itchy rash (hives) that spreads

- Swelling of the face, lips or throat

- Sudden wheezing or tightness in the chest

- A feeling of faintness or dizziness after taking a dose

If any of these symptoms show up, it's best to stop taking the medicine and get medical advice straight away. Allergic reactions can escalate quickly, especially in people with asthma or other sensitivities. Don’t wait around thinking it’ll pass. It's better to have it looked at and be told all is fine, than to let a reaction turn serious.

Sometimes, a mild allergy the first time can become more intense the next time the same medicine is used. That’s why it’s important to document any reaction, even if you managed it at home. Having an allergy noted in your records means it won't be prescribed to you again later.

Neurological And Psychological Symptoms Aren’t Always Just in Your Head

While most people think of antimalarial tablets as targeting parasites in the blood, some types can also affect the brain. For a small number of users, neurological or psychological effects may creep in after starting treatment. These symptoms can catch people off guard, especially if they're dismissed as travel stress or jet lag.

Pay attention to:

- New or increased anxiety or panic

- Feelings of confusion, paranoia or detachment

- Strange or intense dreams, even if you've had sleep issues before

- Mood swings that feel out of character

- Hallucinations or trouble focusing

Some of these might start slowly and build over time. One common sign that it’s medication-related is if symptoms improve when the medication is stopped. But because stopping an antimalarial suddenly without alternative protection isn’t recommended, don’t make changes on your own.

If you're abroad and far from home, it might feel easy to ignore these changes, especially if they seem manageable. Still, mental health is just as important to your safety. Speak to someone you trust and get medical help if things start to feel wrong. Changes in behaviour or thinking shouldn’t be brushed off, even during travel.

Keep An Eye On Blood Sugar Levels

Some antimalarial drugs can affect how your body handles blood sugar. This doesn't mean they’ll cause diabetes, but for people who already have diabetes or are managing their levels, this shift can throw things out of balance.

Here’s what to watch for:

- Feeling shaky, sweaty, or lightheaded without doing much

- Sudden tiredness that’s hard to explain

- Blurry vision that comes and goes

- Trouble concentrating at odd times

- Feeling very thirsty or needing to wee more often

These changes could mean your blood sugar is off. It's especially important during long-haul flights or in hot, unfamiliar climates where your routine is already disrupted. If you take medication for type 1 or type 2 diabetes, or even if you’ve just been advised to monitor your levels, it’s smart to keep track.

Consider packing test strips and checking levels more regularly than you would at home. Even something as simple as different mealtimes or missing a dose can throw your numbers off. If you notice odd symptoms, log them and reach out to a health professional for advice.

Your Health Comes First, Wherever You Are

If you're planning a trip abroad, keeping an eye on your health goes well beyond packing the right clothes or applying sunscreen. Seasonal travel in July often includes destinations where malaria is more common. That’s why summer is a peak time to begin antimalarial treatment, especially across places in Africa, Asia and parts of South America. Knowing how your medicine affects you before departure gives you control and peace of mind.

Being informed about red flags, both physical and mental, can make your trip smoother and protect your well-being long after you return home. If something feels off while on medication, trust your instincts. You know your body better than anyone, and small changes can say a lot.

By spotting early warning signs and acting on them, you're doing more than avoiding discomfort. You’re protecting your health and making sure your medication is helping, not hurting. Travel should be a positive experience, and the more you know, the better prepared you’ll be.

To ensure a safe and comfortable trip, it's important to stay informed about any medication you take. For those also looking to maintain their skin routine while travelling, you can explore our range of products designed for skincare in London at Leyton Pharmacy. Your health and well-being are worth prioritising, and we're here to support you every step of the way.