At a glance
- Nausea and diarrhoea are among common side effects.
- Feeling tired may be related to the illness, the medicine or something else.
- Alcohol advice varies between antibiotics.
- Breathing difficulty or swelling can signal a serious allergic reaction.
Common effects and what to ask
Stomach upset, nausea and diarrhoea are possible with many antibiotics. A pharmacist can advise whether an effect is expected for your medicine, how to manage it safely and when it needs assessment.
Fatigue is not proof that an antibiotic is the cause: infections themselves often leave people feeling drained. Persistent or worsening symptoms deserve a conversation with a healthcare professional.
Interactions depend on the specific medicine
Some antibiotics interact with other prescription medicines, supplements, hormonal contraception or alcohol. For example, NHS guidance highlights restrictions for metronidazole and tinidazole, and an interaction between rifampicin and some hormonal contraception. Always check the particular medicine and disclose everything you take.
When to seek urgent help
Get urgent medical help if you have trouble breathing, swelling of the mouth or throat, or a severe blistering rash. These may indicate a serious reaction. For other unexpected or persistent effects, contact your pharmacist or clinician promptly.
Sources
Original referencesThese sources informed this overview. Their organisations do not endorse or review this website.
This page is for general education only. It does not replace advice from a doctor, pharmacist or other qualified healthcare professional. Read our medical disclaimer.