Antibiotics for viral infections

Taking an antibiotic for a cold, influenza, or another uncomplicated viral illness will not clear the virus. It can still cause diarrhoea, nausea, rash, allergic reactions, or disruption of the body's usual bacteria.

Viruses and bacteria can both cause fever, cough, sore throat, tiredness, and nasal symptoms. Mucus colour alone does not establish that an illness is bacterial. A clinician considers the pattern of symptoms, examination findings, underlying health, and sometimes testing before deciding whether an antibiotic has a role.

A bacterial infection can occasionally develop during or after a viral illness. In that situation, an antibiotic targets the bacterial complication rather than the original virus. Using antibiotics only when indicated also reduces selective pressure that allows resistant bacteria to persist.

Rest, drink enough fluid to avoid dehydration, and choose symptom relief that is safe with your health conditions and regular medicines. A pharmacist can help check whether a pain reliever, fever medicine, or decongestant is suitable. Follow any infection-control guidance relevant to the illness.

If an antibiotic is later prescribed for a confirmed or suspected bacterial problem, follow its label and the prescriber's instructions. Never share antibiotics, use old supplies, or pressure someone else to prescribe them for reassurance.

Seek urgent help for trouble breathing, blue or grey lips, chest pain, confusion, fainting, a stiff neck, a seizure, severe dehydration, or a rapidly worsening condition. Arrange review when symptoms improve and then become distinctly worse, fever persists with deterioration, or a person at higher medical risk is struggling to recover.

Ask which findings suggest a viral rather than bacterial cause, how long to monitor the symptoms, what specific changes should trigger reassessment, and whether testing would affect treatment. If an antibiotic is offered, ask which bacterial infection it is intended to cover.