Promethazine Uses, Dosage, and Side Effects Overview

Promethazine: Summary and Key Points

Promethazine is a prescription medication used to treat a variety of conditions, including allergies, nausea, vomiting, and motion sickness. It can also be prescribed as a sedative or to alleviate cold symptoms. Promethazine works by blocking histamine, a substance in the body that triggers allergic reactions. Always consult your healthcare provider before starting or adjusting your dose.

Names of Medication: Promethazine and Phenergan

US Brand Name: Phenergan (Promethazine)

The generic name refers to the chemical name of the active ingredient. In this case, the generic name is listed in parentheses.

Pharmacologic Category of Promethazine

Antihistamine, First Generation

Antiemetic (prevents nausea and vomiting)

Phenothiazine Derivative

Promethazine Dosage Guidelines

Promethazine is prescribed for a range of conditions, and the dosage and frequency depend on the specific condition being treated. Always follow your healthcare provider’s instructions and consult them before making any changes to your dose. You can also schedule a telemedicine visit with one of our providers for personalized advice.

Promethazine for Allergic Rhinitis

Dosage: 25 mg at bedtime or 12.5 mg before meals and at bedtime

Frequency: Once daily or as needed

Length of Treatment: As directed by your healthcare provider

Promethazine for Motion Sickness

Dosage: 25 mg taken 30 to 60 minutes before travel

Frequency: May repeat every 12 hours as needed

Length of Treatment: As needed for travel

Promethazine for Nausea and Vomiting

Dosage: 12.5 to 25 mg every 4 to 6 hours as needed

Frequency: Every 4 to 6 hours

Length of Treatment: As needed for symptom relief

Promethazine for Insomnia

Dosage: 25 to 50 mg at bedtime

Frequency: Once daily

Length of Treatment: As directed by your healthcare provider

Promethazine for Urticaria (Hives)

Dosage: 25 mg at bedtime or 12.5 mg before meals and at bedtime

Frequency: Once daily or as needed

Length of Treatment: As directed by your healthcare provider

Promethazine for Anaphylaxis (Adjunctive Treatment)

Dosage: 25 mg once, followed by 12.5 to 25 mg every 4 to 6 hours as needed

Frequency: Every 4 to 6 hours

Length of Treatment: As directed by your healthcare provider

Promethazine for the Common Cold

Dosage: 25 mg at bedtime

Frequency: Once daily

Length of Treatment: As needed for symptom relief

Promethazine for Vertigo

Dosage: 25 mg every 4 to 6 hours as needed

Frequency: Every 4 to 6 hours

Length of Treatment: As directed by your healthcare provider

Promethazine for Preoperative Sedation

Dosage: 25 to 50 mg once

Frequency: Given before surgery

Length of Treatment: Single dose

Dosage Forms and Strengths of Promethazine

Tablets: 12.5 mg, 25 mg, 50 mg

Suppositories: 12.5 mg, 25 mg, 50 mg

Injection: 25 mg/mL, 50 mg/mL

Syrup: 6.25 mg/5 mL

Administration Instructions for Promethazine

Promethazine can be taken orally, as a rectal suppository, or by injection. Tablets or syrup can be taken with or without food. For suppositories, follow the instructions for proper insertion. Injections should only be administered by a healthcare professional. Always follow your doctor’s instructions carefully.

Promethazine Side Effects and Adverse Reactions

Like all medications, Promethazine may cause side effects. Some are common, while others are rare but more serious. If you experience severe side effects, contact your healthcare provider immediately or seek emergency care.

1. Drowsiness: Feeling unusually sleepy or fatigued (common)
2. Dizziness: Feeling lightheaded or unsteady (common)
3. Dry mouth: A lack of saliva, leading to a dry mouth (common)
4. Blurred vision: Difficulty seeing clearly (less common)
5. Confusion: Trouble thinking clearly or concentrating (less common)
6. Severe allergic reactions: Swelling, rash, or difficulty breathing (rare, but serious)
7. Respiratory depression: Slow or shallow breathing (rare, but serious)

Contraindications for Promethazine Use

A contraindication is a specific situation where a treatment or medication should not be used because it may be harmful. For Promethazine, several conditions make it unsafe to take.

1. Children under 2 years of age: Promethazine is contraindicated in children younger than 2 due to the risk of severe breathing problems, which can be life-threatening.
2. Severe respiratory issues: Patients with conditions like asthma or chronic obstructive pulmonary disease (COPD) should avoid Promethazine as it can suppress breathing and worsen these conditions.
3. Allergy to Promethazine or similar medications: If you have had an allergic reaction to Promethazine or other phenothiazines, you should not take this medication to avoid serious allergic reactions.
4. Comatose state: Promethazine should not be used in patients in a coma, as it can further depress the central nervous system.
5. Severe liver disease: Promethazine is processed by the liver, and in cases of severe liver disease, it may not be metabolized properly, leading to toxicity.

Drug to Drug Interactions

Promethazine can interact with other medications, potentially increasing the risk of side effects or reducing the effectiveness of either drug. It’s important to inform your healthcare provider about all the medications you are taking, including over-the-counter drugs and supplements. Some common drug interactions include:

1. Opioid pain medications: (e.g., OxyContin [oxycodone], Vicodin [hydrocodone]) – Combining these with Promethazine can significantly increase the risk of severe drowsiness, breathing difficulties, and even life-threatening complications.
2. Antidepressants: (e.g., Zoloft [sertraline], Prozac [fluoxetine]) – Taking Promethazine with certain antidepressants can raise the risk of serotonin syndrome, a potentially dangerous condition that requires immediate medical attention.
3. Antihistamines: (e.g., Benadryl [diphenhydramine], Claritin [loratadine]) – Using additional antihistamines alongside Promethazine can lead to excessive drowsiness and dry mouth, which may impair daily activities.
4. Blood pressure medications: (e.g., Norvasc [amlodipine], Lisinopril) – Promethazine can lower blood pressure, so combining it with blood pressure medications may result in dangerously low blood pressure, leading to dizziness or fainting.
5. MAO inhibitors: (e.g., Nardil [phenelzine], Parnate [tranylcypromine]) – These medications can intensify the effects of Promethazine, causing profound sedation and other serious side effects.

Promethazine in Pregnancy

Is Promethazine Safe During Pregnancy?

Promethazine is classified as a Category C drug for pregnancy by the FDA. This means that while there are no well-controlled studies in pregnant women, animal studies have shown potential risks to the fetus. Promethazine should only be used during pregnancy if the potential benefits outweigh the risks. If you are pregnant or planning to become pregnant, it’s essential to consult your healthcare provider before taking Promethazine. Our telemedicine providers are available to help you make an informed decision about your treatment options.

Promethazine While Breastfeeding

Is Promethazine Safe While Breastfeeding?

Promethazine is generally not recommended while breastfeeding. The medication can pass into breast milk and may affect a nursing infant, potentially causing excessive drowsiness, irritability, or breathing problems. If you are breastfeeding, it’s important to discuss alternative treatments with your healthcare provider. Our telemedicine team can guide you through safe options for managing your symptoms while breastfeeding.

Estimated Cost of Promethazine

The cost of a 30-day supply of Promethazine without insurance can vary depending on the pharmacy and location. Using a GoodRX coupon, the estimated cost for a 30-day supply of Promethazine (25 mg tablets) is approximately $10 to $15. Prices may fluctuate, so it’s a good idea to check with your pharmacy or use a discount service like GoodRX for the most up-to-date pricing.

Possible Alternatives to Promethazine

If Promethazine is not suitable for you, or if you are exploring alternative treatments, there are other medications and lifestyle changes that may help manage your symptoms. Always consult your healthcare provider before making any changes to your treatment plan. Our telemedicine providers are available to discuss these options with you.

1. Allergic rhinitis: Alternatives may include antihistamines like loratadine (Claritin) or cetirizine (Zyrtec), nasal corticosteroids such as fluticasone (Flonase), or lifestyle adjustments like avoiding allergens and using air purifiers.
2. Motion sickness: Non-drowsy alternatives include meclizine (Dramamine Less Drowsy) or scopolamine patches. Behavioral techniques, such as focusing on the horizon or using acupressure wristbands, may also provide relief.
3. Nausea and vomiting: Alternatives include ondansetron (Zofran) or ginger supplements. Staying hydrated and eating small, bland meals can also help manage nausea.
4. Insomnia: Non-medication alternatives include melatonin supplements, cognitive behavioral therapy for insomnia (CBT-I), and practicing good sleep hygiene, such as maintaining a consistent sleep schedule and avoiding screens before bed.
5. Urticaria (hives): Alternatives include antihistamines like fexofenadine (Allegra) or cetirizine (Zyrtec). Avoiding known triggers and applying cool compresses may also help alleviate symptoms.
6. Anaphylaxis: In cases of severe allergic reactions, epinephrine (EpiPen) is the first-line treatment. Always carry an epinephrine auto-injector if you are at risk for anaphylaxis.
7. Common cold: Alternatives include over-the-counter decongestants like pseudoephedrine (Sudafed), saline nasal sprays, and rest. Staying hydrated and using a humidifier can also help relieve symptoms.
8. Vertigo: Alternatives include meclizine (Antivert) or vestibular rehabilitation therapy, which involves exercises to improve balance and reduce dizziness.
9. Preoperative sedation: Alternatives may include benzodiazepines like lorazepam (Ativan) or midazolam (Versed), which are commonly used for sedation before surgery.

Recent Updates on Promethazine Research

Recent studies have focused on the safety and effectiveness of Promethazine, particularly in pediatric and elderly populations. Some research has raised concerns about the potential for respiratory depression in young children, leading to stricter guidelines on its use in this age group. Additionally, ongoing research is exploring the use of Promethazine in combination with other medications for pain management and nausea control in cancer patients. While Promethazine remains widely used, healthcare providers are becoming increasingly cautious about its use in vulnerable populations. If you have concerns about the latest research or how it may affect your treatment, our telemedicine providers are available to discuss your options.

James Kingsley

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