3 Side Effects and Adverse Reactions
Learn how to recognize possible medicine side effects and adverse reactions, respond to symptoms of different levels of urgency, and seek appropriate professional help.
Recognize possible reactions
A is an unwanted effect that may occur with a medicine; effects can range from mild to serious. An is an unwanted or harmful response associated with a medicine. Reactions may also result from allergies or interactions with other medicines, supplements, foods, or health conditions.
Possible effects and the appropriate response depend on the specific medicine. Check its label and ask a pharmacist or prescriber when unsure.
Respond to mild symptoms
For a mild symptom, such as dry mouth when eating, drinking, and breathing remain normal, record when it began, how severe it is, and whether it changes. Ask a pharmacist or prescriber whether the symptom is expected and how to manage it safely.
Do not change the dose or stop a prescribed medicine without appropriate advice. A mild symptom may still need attention if it worsens or persists.
Get prompt advice for new or alarming symptoms
A new rash after starting a medicine can have different causes and levels of seriousness. Contact a pharmacist or prescriber promptly for advice about the medicine and whether to take another dose. Do not assume the rash is harmless or take someone else’s medicine for it.
Seek urgent medical advice for new, severe, or alarming symptoms. Black, tarry stools together with unusual weakness are possible serious warning signs. Tell the clinician the medicine’s name and dose, and when the symptoms began.
Recognize emergency warning signs
Difficulty breathing, swelling of the tongue or throat, or fainting may signal a life-threatening emergency. Call 911 immediately; do not wait for a routine appointment. Call 911 as well if a rash is accompanied by breathing difficulty, mouth or throat swelling, fainting, or rapid worsening.
Follow medicine-specific instructions and get professional advice before changing or stopping a medicine, except when emergency responders direct otherwise.
Make medicine decisions with appropriate guidance
When responding to a suspected , distinguish between symptoms that need emergency help and those that need professional advice. Do not take an extra dose, double a later dose, stop all medicines, or ignore new changes as a substitute for getting appropriate guidance.
Decisions about continuing, changing, or stopping a specific medicine should account for its instructions and the patient’s situation. For mild symptoms, contact a pharmacist or prescriber before changing the dose; for severe symptoms such as trouble breathing or throat swelling, call 911.