How to tell if a new medicine doesn't agree with you

How to tell a mild side effect from a serious reaction, how to keep a record and who to turn to in each case.

To tell whether a new medicine does not agree with you, look at three things: whether the symptom appeared after you started it, whether it is listed in the side effects section of the leaflet, and whether it is mild or a warning sign. If it is mild, mention it to your pharmacist or doctor without stopping the medicine; if it is serious, get urgent help.

Here is a practical guide to telling one situation from another, keeping a simple record and knowing who to turn to in each case.

Is it normal to feel something odd when starting a new medicine?

Yes, it is quite common. Many side effects are mild and tend to disappear or become easier to live with as your body adjusts, often within a few days or weeks. MedlinePlus explains this, for example, for blood pressure medicines: most side effects are mild and may go away over time.

That does not mean you should put up with anything. An effect that stops you living normally, does not improve or worries you deserves a consultation, because it can often be solved by changing the time of the dose, the dose itself or the medicine. That decision belongs to your doctor.

Before you start, it is a good idea to ask which effects to expect. There is a list of questions in what to ask your pharmacist when you are given a new medicine.

How do you tell a mild effect from a reaction that needs urgent attention?

The difference lies in the intensity and the type of symptom. A side effect is usually predictable and mild, such as nausea; an allergy is an immune system reaction that can cause hives, itching or swelling, and in its severe form (anaphylaxis) it is an emergency.

Bear timing in mind: according to MedlinePlus, allergy symptoms can start straight away or several hours after a dose, and some delayed reactions appear a week or more later. That is why it helps to link any new symptom to recent changes in your medication.

How can you tell whether the symptom is related to the medicine?

The best tool is a simple record during the first few weeks. Writing down dates and symptoms shows whether there is a link with the medicine and gives very useful information to whoever sees you.

• Start date of the new medicine and the time you take it.
• What you notice, when it starts, how long it lasts and how intense it is (for example, from 1 to 10).
• Other changes in those days: another medicine, a supplement, alcohol, a different meal, less sleep.

Then check section 4 of the leaflet, "Possible side effects". They are grouped by frequency: "very common" ones may affect more than 1 in 10 people and "rare" ones up to 1 in 1,000. If the text is hard to follow, how to read the leaflet without getting lost explains it step by step.

Also look out for an inverted black triangle (▼). The AEMPS explains that it means the medicine is subject to additional monitoring, usually because it is recent or there is less long term data, and makes clear this does not mean it is less safe.

What should you do and who should you turn to?

First, do not stop taking the medicine without asking, unless it is a severe reaction and the emergency services tell you to. Stopping some treatments suddenly can be worse than the effect you are trying to avoid.

1. Pharmacist: the first step for questions about mild effects, timing or interactions with what you already take.
2. GP: if the effect persists, limits you or you think you need a change. Take your record and your medication list.
3. 112: for any of the warning signs in the table above.
4. notificaRAM.es: citizens can report suspected adverse reactions directly to the AEMPS. Reporting does not replace a consultation, but it helps build knowledge about medicine safety.

If you have ever had an allergy to a medicine, make sure it is recorded in your medical history. More information in what a medicine allergy is and how to spot it.

A practical example: Luis, 63, and the cough that would not go away

Let us take the case of Luis, 63, a taxi driver whose doctor prescribes a new blood pressure medicine from the ACE inhibitor group. Three weeks later he develops a dry cough that does not improve with syrups and bothers him especially at night.

• Luis checks the leaflet and sees that cough is listed among the common side effects. The NHS describes a persistent dry cough as a common effect of this type of medicine.
• He does not stop the tablet: he asks at his pharmacy, where they advise him to mention it to his doctor.
• He notes on his phone when the cough started and when it gets worse.
• At the appointment, his doctor looks at the record and decides whether to change the treatment.

Luis neither stayed in doubt nor abandoned his treatment. Having the data written down made the appointment shorter and more useful.

How can IMA Health help when your treatment changes?

When a new medicine comes in, what matters is that it fits properly with the rest of your treatment. At IMA Health we coordinate with a specialised pharmacy that prepares your medication by day and time of each dose, you receive it at home and we provide personalised follow-up so that every change your doctor decides is reflected in your doses.

Sources

• AEMPS: Electronic reporting of suspected adverse reactions by citizens (notificaRAM) (in Spanish)
• AEMPS: Medicines subject to additional monitoring (▼) (in Spanish)
• CIMA (AEMPS): sample leaflet, section 4 "Possible side effects" (in Spanish)
• MedlinePlus: Drug allergies (in Spanish)
• NHS: Side effects of ramipril

This article is for information only and does not replace advice from your doctor or pharmacist.