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Promethazine Cough Syrup Review: How Much Is Effective?

promethazine cough syrup

Promethazine was made in the 1940s by scientists working at Rhône-Poulenc laboratories. In 1951, this medication was approved in the U.S. By 2019, and Promethazine became the 174th most commonly prescribed medicine in the U.S. after reaching 3 million prescriptions.

Promethazine belongs to the class of drugs called phenothiazine. Promethazine is an antihistamine used with other medications to treat anaphylaxis (sudden, severe allergic responses) and cold symptoms like sneezing, coughing, and runny nose.
Patients are also sedated and relaxed with Promethazine before and after surgery, during childbirth, and other times.

How Does Promethazine Cough Syrup Work?

Promethazine works by blocking some cells in your body from releasing a chemical called histamine. Histamine is regularly released when you’re allergic to something, such as pollen, dander, mold, or chemicals.

This medicine promotes drowsiness and aids in pain management by blocking histamine production. This is since histamine aids in the regulation of wakefulness, keeping you aware and your senses heightened.

This medication also works to lessen the activation of the portion of your brain that causes you to vomit.

What Does Promethazine Treats?

Promethazine Cough Syrup works as medication for flu, allergies, common cold, and other respiratory disorders (e.g., sinusitis, bronchitis). Promethazine, an antihistamine, watery eyes, itchy eyes, runny nose, and sneezing are all relieved.
Discuss the risks and advantages of this drug with your doctor.

Promethazine Dosages

This medication’s dosage will differ depending on the patient. Take medicine as advised. Only the usual doses of this drug are included in the information provided. If your dose varies, do not alter it unless your doctor recommends you.
For relief of symptoms caused due to allergies or the common cold, the recommended dosage is:

  • Adults and children aged 12 and above: Every 4 to 6 hours, take 5 milliliters (ml) (1 tablespoon). Take no more than 30 ml in 24 hours.
  • Children from 6 to 11 years of age: Every 4 to 6 hours, take 2.5 to 5 ml (0.5 to 1 teaspoonful). Take no more than 30 mL in 24 hours.
  • Children less than 6 years of age—Use isn’t recommended.

What To Do If You Forget The Dosage?

  • Take this drug as soon as you remember, in case you miss a dose.
  • Skip the missed dose and return to your regular dosing plan if your next dose is approaching.
  • Do not take two doses together at the same time.

What Should You Do If You Overdose?

Feeling restless or anxious, severe sleepiness, dizziness, dry mouth, big pupils, flushing, nausea, vomiting, shallow breathing, and fainting are symptoms of a promethazine overdose. Get emergency medical help.

Possible Side Effects:

Side effects are possible with Promethazine. If any of these symptoms are too serious or don’t go away, contact your doctor:

  • Difficulty falling asleep or staying asleep.
  • Nightmares.
  • Dry mouth.
  • Drowsiness.
  • Ringing in ears.
  • Blurred or double vision.

Other Drug Interactions:

  • 659 medications interact with Promethazine; here are a few major drugs:
  • Ambien (zolpidem)
  • Lexapro (escitalopram)
  • Topamax (topiramate)
  • Zoloft (sertraline)
  • Benadryl (diphenhydramine)
  • Flexeril (cyclobenzaprine)

Study On Its Effectiveness:

According to the National Institutes of Health (N.I.H.). Promethazine is a histamine receptor antagonist. Histamine receptors are proteins that bind to histamine to trigger allergic reactions. As a result, Promethazine is a powerful antihistamine.
The medication also inhibits cholinergic receptors, effective for nausea, morning sickness, and cough prevention and treatment.
Promethazine can only aid with symptom management. It’s ineffective in treating the underlying source of symptoms or accelerating recovery.


  • If you’re 65 or older, talk to your doctor about the risks and advantages of taking Promethazine. Promethazine is not recommended for usage by older adults since it is not as safe as alternative drugs that can be used to treat the same symptoms.
  • Inform your doctor that you are taking Promethazine if you have surgery, including dental surgery.
  • Ask your doctor if you may drink alcohol safely while on this medicine. The effects of Promethazine can be worsened by alcohol.
  • Wear protective clothing, sunglasses, and sunscreen to avoid needless or prolonged exposure to the sun. Promethazine might make your skin photosensitive.
  • This medication causes drowsiness. Do not indulge in driving.
  •  If you’re providing Promethazine to a youngster, keep an eye on them to ensure they don’t get injured while doing any activity.
  •  A swollen prostate or urinary issues.
  •  Heart illness or hypertension, as well as liver disease.
  •  Hypocalcemia (low calcium in the blood)


  • Here are a few other options for Promethazine:
  • Zofran
  • Zofran ODT
  • Zuplenz
  • Adgan
  • Anergan 50
  • Antinaus 50
  • Phenadoz
  • Promethegan

How to Get Promethazine Cough Syrup Online?

Consumers can buy promethazine cough syrup or different chesty cough syrup through a private service provided by various internet pharmacies. Patients are frequently prompted to fill out an online questionnaire, which a doctor then evaluates, subsequently provides the prescription, and ships the product to the patient. The pharmacies have licenses, and the retailers can sell the medication legally and safely.

In most cases, the cost of an antibiotic eye drop is included in the purchase price; however, this varies per pharmacy.


Promethazine belongs to the phenothiazine class of medication. It operates by preventing a natural chemical Histamine in the body from doing its job. Promethazine can aid with symptom control, but it won’t treat the underlying cause of the symptoms or hasten recovery. It’s best to take Promethazine with other medications, as advised by your doctor.

Quick F.A.Q.

For how much time does promethazine stay in your system?
Promethazine will be mostly gone from your system in two to four days. The time it takes for a medication's blood levels to be reduced by half is known as its elimination half-life. Promethazine has a half-life of about 10 to 19 hours.
Is promethazine addictive?
Addiction to Promethazine is dangerous and detrimental to one's health. Individuals who choose to participate in recovery can learn to live without the Antihistamine. Thousands of people have been able to overcome their addictions.
Is promethazine a narcotic?
No, Promethazine is not a narcotic, despite the term being widely overused and used to refer to any unlawful substance.