Promethazine-DM is a combination cough syrup containing the drugs promethazine and dextromethorphan. It is used to temporarily relieve coughs and upper respiratory symptoms associated with allergies or the common cold. Promethazine is an antihistamine that helps reduce symptoms like runny nose, sneezing, and watery eyes, while dextromethorphan (DM) is a cough suppressant that reduces coughing.
What are the active ingredients in Promethazine-DM?
The active ingredients in Promethazine-DM cough syrup are:
- Promethazine hydrochloride – an antihistamine that relieves watery eyes, runny nose, sneezing, and other allergy symptoms
- Dextromethorphan hydrobromide (DM) – a cough suppressant that reduces cough frequency and intensity
Promethazine belongs to a class of medications called phenothiazines. As an antihistamine, it works by blocking the effects of histamine, a chemical in the body that causes allergy symptoms. Dextromethorphan is a type of cough suppressant called an antitussive that acts on the brain to reduce the urge to cough.
What types of coughs and symptoms does Promethazine-DM treat?
Promethazine-DM is used to relieve coughing and upper respiratory symptoms associated with:
- Allergies
- Colds
- Flu
- Hay fever
- Sinus infections
- Upper respiratory infections
The antihistamine promethazine helps treat runny nose, sneezing, watery eyes, and other allergy symptoms. The dextromethorphan cough suppressant provides temporary relief for coughing caused by minor throat and bronchial irritation.
Promethazine-DM can also sometimes be used short-term to relieve coughs caused by inhaled irritants, such as pollution or cigarette smoke.
How does Promethazine-DM work?
Promethazine-DM relieves coughs and allergy symptoms through the actions of its two active ingredients:
Promethazine
- Blocks histamine receptors – prevents histamine from binding and reduces effects like sneezing, runny nose, watery eyes, and itching
- Has anticholinergic properties – dries up excess secretions by blocking another chemical messenger called acetylcholine
- Sedating effects – calms overactive reflexes like repetitive coughing or sneezing
Dextromethorphan (DM)
- Cough suppressant – acts on the brain to suppress the cough reflex
- Analgesic effects – may reduce throat pain and discomfort associated with coughing
By reducing histamine effects and suppressing the urge to cough, the combination medication provides relief for allergy and cold symptoms.
What are the uses and indications of Promethazine-DM?
The main uses and indications for Promethazine-DM cough syrup include:
- Relieving coughs from colds, flu, and throat irritations
- Suppressing coughs to help sleep
- Temporarily relieving allergy symptoms like runny nose and sneezing
- Reducing post-nasal drip coughs
Promethazine-DM can also sometimes be used before surgery to reduce respiratory secretions and prevent coughing.
It should only be used for short periods up to 1 week for temporary cough relief. The medication is not intended for chronic coughs or coughs caused by smoking, asthma, emphysema, or other underlying lung conditions.
What are the side effects of Promethazine-DM?
Possible side effects of Promethazine-DM include:
- Drowsiness or sedation
- Dizziness
- Nausea
- Vomiting
- Constipation
- Stomach pain
- Blurred vision
- Dry mouth and throat
- Ringing in the ears
Promethazine can cause drowsiness, impaired coordination, and increased effects from alcohol. Use caution when driving or operating machinery.
See a doctor if you experience severe side effects like fainting, fast heartbeat, tremors, confusion, or seizures.
What medications may interact with Promethazine-DM?
Some medications that may interact with Promethazine-DM include:
- Monoamine oxidase inhibitors (MAOIs) – increased risk of side effects
- Central nervous system (CNS) depressants like benzodiazepines or narcotic pain relievers – increased sedation
- Anticholinergics like amantadine – increased anticholinergic side effects
- Epinephrine – impaired epinephrine effects for severe allergic reactions
Always inform your doctor of all medications you are taking before using Promethazine-DM. The cough syrup should not be used in children under 4 years old.
What are the differences between Promethazine-DM and other cough syrups?
Cough Syrup | Key Differences |
---|---|
Promethazine with Codeine | Contains opioid codeine instead of DM as cough suppressant |
Cheratussin AC | Does not contain antihistamine, only dextromethorphan and guaifenesin expectorant |
Robitussin with DM | Does not contain antihistamine, only dextromethorphan as cough suppressant |
Mucinex DM | Contains guaifenesin expectorant instead of antihistamine |
Delsym | Contains extended release dextromethorphan only |
The combination of promethazine antihistamine and dextromethorphan cough suppressant makes Promethazine-DM unique. It provides relief for both allergy symptoms and coughs.
What strengths and forms does Promethazine-DM come in?
Promethazine-DM is available in the following strengths and forms:
- Oral solution – 6.25mg promethazine HCl and 15mg dextromethorphan HBr per 5mL
- Syrup – 6.25mg/5mL promethazine and 15mg/5mL dextromethorphan
- Tablets – 12.5mg promethazine and 15mg dextromethorphan
- Rectal suppositories – 12.5mg/25mg promethazine and 15mg/30mg dextromethorphan
The oral syrup is the most common formulation used. Usual doses for adults and children over 12 years old are 10-20mL every 4-6 hours as needed.
Does Promethazine-DM cause drowsiness or make you sleep?
Yes, one of the side effects of Promethazine-DM is drowsiness or sedation. The antihistamine promethazine has sedating effects that can make some people very sleepy. It may help suppress coughs at night and allow sleep.
Do not drive or operate machinery after taking Promethazine-DM until you know how it affects you. Avoid alcohol and other sedatives that could increase the drowsiness.
If daytime drowsiness is severe, talk to your doctor about switching to a non-sedating antihistamine. There are also dextromethorphan-only cough syrups available without the promethazine.
Is Promethazine-DM safe for kids and what’s the dosage?
Promethazine-DM can typically be used safely in children over 2 years old. For kids 2-5 years old, the usual dosage is:
- 2.5mL syrup every 4-6 hours as needed
For children 6-11 years old, the common dosage is:
- 5mL syrup every 4-6 hours as needed
Read drug labels carefully and always follow your doctor’s dosage instructions. Do not give Promethazine-DM to children under 2 without medical supervision.
Use caution due to the risk of severe drowsiness. Avoid giving cough medicine before school or activities if it makes your child very sleepy.
Can you take Promethazine-DM when pregnant or breastfeeding?
Promethazine-DM has not been shown to cause birth defects or other problems during pregnancy. However, as a precaution, it should only be used if clearly needed and under medical supervision in pregnant women.
Promethazine and dextromethorphan can pass into breast milk in small amounts. Talk to your doctor about use while breastfeeding. Potential effects on the nursing infant include drowsiness, fussiness, and breathing issues in rare cases.
How long does Promethazine-DM take to work?
Promethazine-DM starts working within 15-30 minutes after taking a dose. The effects typically last for 4-6 hours.
The promethazine antihistamine works quickly to relieve allergy symptoms like runny nose and sneezing. The dextromethorphan cough suppressant peaks around 1-2 hours and provides longer lasting relief for coughs.
How long does Promethazine-DM stay in your system?
Promethazine-DM stays in your system with an overall duration of action of 4-6 hours per dose. However, trace amounts can be detected for longer:
- Promethazine – metabolites detectable for 1-2 days
- Dextromethorphan – detectable up to 5-7 days after last use
People with impaired kidney or liver function can retain medications longer in the body. Promethazine-DM should not be used for more than 1 week except under medical direction.
Does Promethazine-DM show up on a drug test?
Promethazine will not cause false positives on standard drug tests like a 5-panel urine screen. However, dextromethorphan can trigger a false positive for PCP and opioids like morphine.
Confirmation testing can differentiate dextromethorphan from other drugs. But very high doses of dextromethorphan might directly be detected on extended opiate urine tests.
What precautions should be taken with Promethazine-DM?
Some key precautions with Promethazine-DM include:
- May cause drowsiness – use caution when driving
- Avoid alcohol while taking
- Do not use if you have breathing issues like COPD or sleep apnea
- Use caution in children due to greater risk of severe side effects
- Avoid use in first trimester of pregnancy due to risks
- Only use for the short term – consult doctor if symptoms persist longer than 1 week
Promethazine-DM is relatively safe when used occasionally and as directed for temporary relief. But misuse or long-term use can increase risks of complications.
Can you buy Promethazine-DM over the counter?
Yes, Promethazine-DM is available for purchase over-the-counter (OTC) without a prescription in the United States. It is sold under various brand names including Phenergan with Dextromethorphan.
There are also generic versions sold in most pharmacies and many grocery/retail stores. OTC products contain lower doses of promethazine and DM compared to prescription strengths.
When should you see a doctor about cough symptoms?
See a doctor if you experience any of the following:
- Cough lasts longer than 1 week
- Cough does not respond to OTC medication
- Cough returns again after getting better
- Cough produces thick, colored mucus
- Cough accompanied by fever above 101 F
- Shortness of breath or wheezing with cough
- Chest pain or tightness when coughing
Promethazine-DM is meant for temporary relief. Seek medical evaluation if your cough persists or gets worse despite treatment.
Conclusion
Promethazine-DM is a combination antihistamine and cough suppressant used for temporary relief of allergy symptoms and coughs. The promethazine component treats runny nose, sneezing, watery eyes from colds or allergies. The dextromethorphan suppresses the cough reflex.
Potential side effects include sedation, dizziness, nausea, and blurred vision. Promethazine-DM should only be used for short periods up to 1 week. See a doctor if your cough lasts longer or you experience concerning symptoms like high fever, wheezing, or chest pain.