Side effects: what to expect and how to handle them

Side effects are the unwanted reactions some people get from medicines. They range from mildly annoying—like dry mouth—to serious, like breathing problems. Knowing what to expect makes it easier to stay safe and keep treatment on track.

Common types of side effects

Digestive problems: nausea, diarrhea, constipation, or stomach pain are common. Try taking the medicine with food (when allowed) or ask your pharmacist about an antacid or anti-nausea option.

Central nervous system issues: drowsiness, dizziness, headaches, or trouble sleeping often show up with painkillers, antidepressants, or antihistamines. Avoid driving until you know how a drug affects you.

Skin reactions: rashes, itching, or photosensitivity can appear within hours or days. Mild rashes may settle with an antihistamine, but any swelling of the face or throat needs urgent care.

Allergic and severe reactions: hives, swelling, breathing difficulty, or sudden drop in blood pressure are emergencies. Stop the drug and get medical help right away.

Blood pressure, heart rate, or lab changes: some drugs affect potassium, blood sugar, liver or kidney tests. Your doctor may order blood work to watch for these changes.

Practical steps if you get side effects

Read the leaflet and check timing. The patient information leaflet will list common side effects and whether they usually pass in a few days.

Don’t stop important medicines suddenly. For many drugs—antidepressants, steroids, and some blood pressure meds—stopping abruptly can be worse than the side effect. Call your prescriber to ask about dose changes or alternatives.

Simple fixes: take meds with food, split doses (only if your doctor says it’s okay), drink more water for dry mouth or constipation, and avoid alcohol when the label warns against it.

Watch for interactions. Tell every provider and pharmacist what else you take: prescriptions, OTCs, vitamins, and herbal supplements. Even grapefruit, St. John’s wort, or certain antacids can change how drugs work.

Keep a symptom log. Note when a side effect started, what you were doing, and whether anything helped. This makes conversations with your clinician faster and more useful.

When to seek help: call your doctor if side effects are severe, getting worse, or stopping you from working or sleeping. Go to emergency care for trouble breathing, fainting, chest pain, severe bleeding, or a high fever with rash.

Report problems. Many countries have safety reporting systems (like the FDA MedWatch). Reporting helps make medicines safer for everyone.

Short-term side effects often fade as your body adjusts. If they don’t, ask about changing the dose, switching drugs, or adding a medicine to control the side effect. Clear communication with your healthcare team and a simple plan make side effects manageable without losing the benefit of treatment.