Promethazine vs. Nyquil for Allergic Rhinitis: Important Differences and Potential Risks.

Key takeaways

Promethazine (Phenergan) and acetaminophen/dextromethorphan/doxylamine (Vicks Nyquil Cold and Flu) are both used to treat symptoms like runny nose and sneezing, but they belong to different medication classes. Promethazine is an antihistamine that also has anticholinergic and anti-dopaminergic properties and is used for allergies, nausea, and motion sickness. Nyquil Cold and Flu is a combination medication that includes an analgesic, a cough suppressant, and an antihistamine and is used for cold and flu symptoms. Promethazine is available by prescription in various forms, including tablets, syrup, and injection, while Nyquil Cold and Flu is available over-the-counter as a liquid or capsules. Promethazine can cause drowsiness and dizziness and should not be used in children under 2 years old. Nyquil Cold and Flu can also cause sleepiness and dizziness and should not be used with other medications containing acetaminophen. Both medications can interact with monoamine oxidase inhibitors (MAOIs) like selegiline (Zelapar) or phenelzine (Nardil).

Promethazine

Get free coupons

Nyquil Cold and Flu

Get free coupons

Summary for Promethazine

Prescription only

Promethazine is a prescription medication with many uses, such as treatment or prevention of nausea, motion sickness, and allergy symptoms. Promethazine works by blocking several chemicals, including histamine, dopamine, and acetylcholine. It comes as tablets, an oral solution, rectal suppositories, and an injection. The dose of promethazine and how often you take it depends on your age and what medical condition you're taking it to treat. But it shouldn't be given to children younger than 2 years of age since it can cause serious breathing problems. Common side effects include sleepiness and dizziness.

Indications for Promethazine

Runny nose, watery eyes, and other symptoms of allergies
Runny or stuffy nose that isn't caused by allergies
Rash, swelling, anaphylaxis, and other symptoms of an allergic reaction
Dermographism
Treatment or prevention of nausea and vomiting before and after surgery
Treatment or prevention of motion sickness
Treatment of pain along with other pain medications after surgery
Help to relax your body and produce a light sleep, particularly before a procedure

Pros and Cons for Promethazine

Pros

Available as a lower-cost generic
Available in different formulations, such as a tablet, syrup, and injection
Starts working within 20 minutes

Cons

Can't be taken by children under 2 years old because risk of serious breathing problem
Higher risk of side effects in older adults
Can cause sleepiness

Common Side Effects for Promethazine

Feeling drowsy or tired
Dizziness
Confusion
Dry mouth
Nervousness
Blurry vision

The following side effects are those additionally reported with promethazine injection at the injection site:

Burning
Pain
Rash
Swelling

Warnings for Promethazine

Potentially life-threatening slow breathing (respiratory depression)
Serious tissue injury (Injection only)
Excessive sleepiness
Worsening of certain health problems
Seizures
Higher risk of infection (from low white blood cell count)
Risk of serious nerve problems (neuroleptic malignant syndrome)
Uncontrollable body movements

Summary for Nyquil

Over-the-counter

Nyquil Cold and Flu is a combination medication containing acetaminophen (a pain reliever), dextromethorphan (a cough suppressant), and doxylamine (an antihistamine). It's used to treat cold and flu symptoms, like sore throat, fever, cough, runny nose, sneezing, and aches, in adults and children. Nyquil Cold and Flu is available as pills and a liquid. This medication can make you feel sleepy and dizzy as side effects.

Indications for Nyquil

Temporarily relieves common cold and flu symptoms, including:

Cough
Sore throat
Headache
Minor aches and pains
Fever
Runny nose
Sneezing

Pros and Cons for Nyquil

Pros

Available over the counter
Works within 30 minutes to relieve cold and flu symptoms
Available in capsules and a liquid
Combines three medications in one product for convenience
Available as a lower-cost generic

Cons

Needs to be taken multiple times per day
Can cause extreme sleepiness
More difficult to customize the dose since it's a fixed combination of three medications
Need to avoid alcohol while taking it
Not meant for long-term use