What it is used for
- Hay fever and other allergies
- Hives (urticaria) and itchy skin
- Itchy, runny nose and sneezing
- Allergic reactions to insect bites or stings
- Sometimes used short-term as part of treating allergic reactions under medical guidance
How it works
Chlorphenamine blocks histamine, easing allergy symptoms such as itching, sneezing, and watering. Because it enters the brain, it often causes drowsiness.
How it is taken
Available as tablets and a liquid syrup, and in some settings as an injection given by a healthcare professional. The oral forms are taken by mouth. Take it exactly as directed by your doctor, pharmacist, or the label, and never exceed the recommended amount.
No doses here on purpose. The right strength and schedule depend on you — only a doctor or pharmacist should set them. Always follow your prescription and the label.
Common side effects
- Drowsiness and sleepiness (common)
- Dry mouth, nose, and throat
- Blurred vision
- Dizziness
- Constipation
- Difficulty passing urine
Serious effects — get help
- Signs of a severe allergic reaction (facial/throat swelling, breathing difficulty)
- Fast or irregular heartbeat
- Confusion, especially in older adults
- Seizures (rare)
If a reaction is severe — for example trouble breathing, swelling of the face or throat, or collapse — go to the nearest emergency room now or call your local emergency number. Do not wait for an online consultation.
Interactions to watch
- Alcohol (markedly increases drowsiness)
- Sleeping tablets, sedatives, and strong painkillers
- Some antidepressants (MAOIs in particular)
- Other medicines with drying/anticholinergic effects
Who should take care
- Tell your clinician if you are pregnant, planning pregnancy, or breastfeeding
- Causes drowsiness — do not drive or operate machinery until you know how it affects you
- Caution in older adults, who are more sensitive to its effects
- Caution with glaucoma, enlarged prostate, urinary problems, epilepsy, or liver problems
- Avoid if allergic to chlorphenamine