Theraflu Warming Relief Daytime Multi-Symptom Cold Caplets Side Effects
Generic name: acetaminophen / dextromethorphan / phenylephrine
Medically reviewed by Drugs.com. Last updated on Aug 21, 2023.
Note: This document contains side effect information about acetaminophen / dextromethorphan / phenylephrine. Some dosage forms listed on this page may not apply to the brand name Theraflu Warming Relief Daytime Multi-Symptom Cold Caplets.
Applies to acetaminophen / dextromethorphan / phenylephrine: oral capsule, oral tablet.
Serious side effects
WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:
- Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
- Signs of liver problems like dark urine, feeling tired, not hungry, upset stomach or stomach pain, light-colored stools, throwing up, or yellow skin or eyes.
- Not able to pass urine or change in how much urine is passed.
- A very bad skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis) may happen. It can cause very bad health problems that may not go away, and sometimes death. Get medical help right away if you have signs like red, swollen, blistered, or peeling skin (with or without fever); red or irritated eyes; or sores in your mouth, throat, nose, or eyes.
Other side effects
All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:
- Feeling nervous and excitable.
- Trouble sleeping.
These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.
For Healthcare Professionals
Serotonin syndrome has been reported with concomitant use of dextromethorphan and either a monoamine oxidase inhibitor (MAOI) or a serotonergic drug such as a selective serotonin reuptake inhibitor (SSRI). Serotonin syndrome causes changes in mental status, restlessness, myoclonus, hyperreflexia, diaphoresis, shivering, tremor, and hypertension.[Ref]
Uncommon (0.1% to 1%): Drowsiness, dizziness, fatigue, dystonias (dextromethorphan)
Frequency not reported: Headache, dizziness, insomnia (phenylephrine)
Postmarketing reports: Serotonin syndrome (dextromethorphan)[Ref]
Postmarketing reports: Allergic reactions (e.g. rash, urticaria, angioedema) (dextromethorphan)[Ref]
Frequency not reported: Increased blood pressure, arrhythmias (phenylephrine)[Ref]
Frequency not reported: Nausea, vomiting (phenylephrine)[Ref]
Frequency not reported: Nervousness, anxiety (phenylephrine)[Ref]
Very rare (less than 0.01%): Bronchospasm (especially in patients sensitive to aspirin/other NSAIDs) (acetaminophen)[Ref]
Rare (less than 0.1%): Dysuria, urinary retention (phenylephrine)[Ref]
Dysuria and urinary retention are most likely to occur with preexisting bladder outlet obstruction (e.g. prostatic hypertrophy)[Ref]
Phenylephrine is most likely to cause mydriasis and acute closure glaucoma in patients with pre-existing closed angle glaucoma.[Ref]
More about Theraflu Warming Relief Daytime Multi-Symptom Cold Caplets (acetaminophen / dextromethorphan / phenylephrine)
- Check interactions
- Compare alternatives
- Dosage information
- During pregnancy
- Drug class: upper respiratory combinations
Related treatment guides
1. Cerner Multum, Inc. Australian Product Information.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Some side effects may not be reported. You may report them to the FDA.