Antihistamines are commonly used throughout the world to relieve sneezing, itching, or a runny nose. They don't help postnasal drip, nasal congestion, or other sinus problems. For those, many people reach for a decongestant.
Antihistamine and decongestant combinations are used to treat the symptoms of the common cold and hay fever. Some combination drugs are only available with a doctor's prescription. Others are available without a prescription.
Many people take cold and allergy medicines and experience very few (if any) side effects from them. But some people have serious reactions to them. Common minor side effects include dry mouth, nervousness, excitability, irritability, unusual sleepiness, weakness, fatigue, loss of appetite, skin rash, urination problems, and a slightly increased heartbeat. But some people develop serious adverse reactions that might require emergency intervention, such as heart rates accelerated to 200 beats per minute.
When to Get Emergency Help
Serious side effects are rare but do occur. They might be more likely to occur if you take too large a dose or use it for a long period of time. The National Institutes of Health recommends that you get emergency help immediately if you experience any of the following:
- Clumsiness or unsteadiness
- Headache (continuing)
- Convulsions (seizures)
- Shortness of breath or troubled breathing
- Drowsiness (severe)
- Dryness of mouth, nose, or throat (severe)
- Flushing or redness of face
- Slow, fast, or irregular heartbeat ("Normal" is 60 to 100 beats per minute for adults. Watch for any change.)
- Trouble sleeping
- Hallucinations (seeing, hearing, or feeling things that aren't there)
If you're taking promethazine, get immediate emergency help if you experience: muscle spasms (especially in the neck and back), restlessness, shuffling walk, tic-like (jerky) movements of head and face, trembling and shaking of hands.
If you have any other side effects, contact a member of your healthcare team. You probably won't need medical intervention, even if the effects are bothersome. Your health provider is in the best position to determine what adjustments, if any, are needed.
Follow Directions
Always carefully read and follow all instructions and precautions. Before reaching for a common medication, you might want to check with your healthcare provider. What you take – and how much you take of it – depends on your medical condition and other medications you're currently taking. Some examples include:
- Pregnancy or breastfeeding
- Age (children and older adults have special needs)
- Alcohol use
- Current medicines (anything from OTC nose drops to diet pills to prescription beta blockers to heart medications)
- Health problems (including glaucoma, diabetes, problems urinating, high blood pressure, thyroid, or kidney or liver disease)
- If you've ever had any unusual or allergic reaction to any medication (prescription or over-the-counter)
Additionally, if you're scheduled for any medical tests or procedures, be sure to tell your doctor that you're using antihistamines or decongestants. |
