Buy Generic Phenergan Online

Generic Phenergan Information

Introduction

Phenergan (promethazine) is a prescription medication classified in the allergy group. It is primarily used for its antihistamine, anti‑emetic, and sedative properties. In Hong Kong, Phenergan is prescribed for allergic reactions, motion sickness, and pre‑operative sedation, among other indications. The drug is marketed by Pfizer and contains the active compound promethazine, a first‑generation H₁‑receptor antagonist with additional central nervous system effects.

What is Phenergan?

Phenergan is a brand‑name formulation that contains 25 mg of promethazine hydrochloride per tablet or 6.25 mg per millilitre of oral solution. The medication belongs to the first‑generation antihistamine class and was first introduced in the 194s. Promethazine blocks histamine H₁ receptors in peripheral tissues, reducing allergic symptoms such as itching, urticaria, and rhinorrhea. In addition to its antihistamine activity, promethazine possesses potent anticholinergic and sedative actions, making it useful for nausea, vomiting, and procedural sedation.

The product is available in several dosage forms, including oral tablets, syrup, injectable solution, and rectal suppositories. While the brand name Phenergan is common in many Asian markets, identical generic versions labeled simply “promethazine” are also distributed, providing cost‑effective alternatives.

How Phenergan Works

Promethazine exerts its therapeutic effect by competitively inhibiting the binding of histamine to H₁ receptors on smooth muscle, endothelial cells, and sensory nerve endings. This blockade prevents the vasodilation, increased vascular permeability, and sensory nerve activation that underlie classic allergic symptoms.

Beyond peripheral H₁ antagonism, promethazine readily crosses the blood–brain barrier. In the central nervous system it antagonizes muscarinic acetylcholine receptors and blocks dopamine D₂ receptors to a lesser extent. The combined antihistaminic, anticholinergic, and dopaminergic effects depress the vomiting centre in the medulla, accounting for its anti‑emetic action. Sedation results from central histamine blockade, similar to other first‑generation antihistamines.

After oral administration, promethazine reaches peak plasma concentrations within 1–2 hours. The drug has a bioavailability of 80–90 % and is highly protein‑bound (≈ 85 %). It is metabolised primarily by hepatic CYP2D6 and CYP3A4 pathways, producing inactive metabolites that are excreted renally. The elimination half‑life ranges from 10 to 19 hours, allowing once‑ or twice‑daily dosing in most adult regimens.

Conditions Treated with Phenergan

• Allergic rhinitis and urticaria – Histamine‑mediated itching, sneezing, and rash respond quickly to H₁‑receptor blockade. In Hong Kong, seasonal pollen and dust‑mite allergies affect up to 25 % of the adult population, making antihistamines a core therapy.
• Motion sickness and postoperative nausea – Central inhibition of the vestibular system and the chemoreceptor trigger zone reduces both nausea and vomiting after travel or surgery. Studies in East Asian cohorts show comparable efficacy to dimenhydrinate.
• Anaphylaxis adjunct – While epinephrine remains the first‑line treatment, Phenergan is sometimes administered after stabilisation to alleviate cutaneous symptoms and prevent biphasic reactions.
• Sedation before diagnostic procedures – Low‑dose oral or injectable promethazine provides anxiolysis and amnesia for minor procedures such as endoscopy or minor dermatologic surgeries.
• Cough associated with upper‑respiratory infections – Its anticholinergic properties suppress cough reflexes, though use is limited to short courses due to sedative risk.

These indications are supported by the Hong Kong Department of Health’s formulary and the product’s approved labeling in many jurisdictions.

Who is Phenergan For?

Phenergan is suitable for adult patients who require rapid control of allergic symptoms, prevention of motion‑induced nausea, or short‑term procedural sedation. Typical clinical scenarios include:

• Adults with moderate‑to‑severe urticaria unresponsive to non‑sedating antihistamines.
• Travelers on long ferry rides, high‑speed trains, or air travel who have a history of motion sickness.
• Patients scheduled for minor surgeries who prefer an oral sedative rather than intravenous agents.

Contraindications limit use in certain groups: patients with known hypersensitivity to promethazine, children under two years of age (due to risk of respiratory depression), and individuals with severe hepatic impairment. Caution is advised for patients with glaucoma, prostatic hypertrophy, or a history of seizures, as anticholinergic and central effects may exacerbate these conditions.

Risks, Side Effects, and Interactions

Common

• Drowsiness or somnolence
• Dry mouth, blurred vision, constipation (anticholinergic effects)
• Dizziness or light‑headedness, especially when standing quickly (orthostatic hypotension)
• Nausea or mild gastrointestinal upset

These events occur in more than 10 % of users and are usually transient. Taking Phenergan with food or at bedtime can mitigate daytime sedation.

Rare

• Extrapyramidal symptoms (tremor, rigidity) – reported in < 1 % of patients, more common in those with pre‑existing Parkinsonian disorders.
• Tachycardia or palpitations – may result from autonomic imbalance.
• Photophobia or increased intra‑ocular pressure – relevant for patients with narrow‑angle glaucoma.

Patients experiencing these symptoms should seek medical advice promptly.

Serious

• Respiratory depression – especially in the elderly, in combination with other central depressants, or when administered intravenously at high doses.
• Severe allergic reaction (anaphylaxis) to the drug itself – manifests as angioedema, bronchospasm, or hypotension.
• Neuroleptic malignant syndrome‑like presentation – rare but characterized by high fever, muscular rigidity, and autonomic instability.

Any sign of serious adverse events warrants immediate medical attention and discontinuation of the medication.

Drug–Drug Interactions

• CNS depressants (benzodiazepines, opioids, alcohol) – additive sedation and respiratory risk.
• Anticholinergic agents (e.g., diphenhydramine, atropine) – may intensify dry mouth, urinary retention, and visual disturbances.
• Monoamine oxidase inhibitors (MAOIs) – increased risk of hypertensive crisis when taken together.
• CYP2D6 inhibitors (e.g., fluoxetine, quinidine) – can raise promethazine plasma levels, potentially worsening side effects.

A comprehensive medication review should be performed before initiating therapy.

Practical Use: Dosing, Missed Dose, Overdose

• Standard adult dosing – 25 mg tablet taken orally every 4–6 hours as needed, not to exceed 100 mg per day for allergy control. For motion sickness, a single 25 mg dose 30 minutes before travel is common. Injectable formulations are dosed at 12.5–25 mg intravenously or intramuscularly in a clinical setting.
• Missed dose – If a scheduled dose is forgotten and more than 4 hours have passed, skip the missed dose and resume the regular schedule. Do not double‑dose to compensate.
• Overdose – Symptoms may include profound sedation, respiratory depression, seizures, and cardiac arrhythmias. Immediate emergency care is required; treatment is supportive with airway protection, oxygen, and intravenous fluids. Activated charcoal may be considered if presentation is within one hour of ingestion.

Precautions – Avoid alcohol and other sedating drugs while using Phenergan. Patients with liver disease should start at the lowest effective dose and monitor for accumulation. Driving or operating machinery is contraindicated until the individual knows how the medication affects them.

Buying Phenergan from Our Online Pharmacy

Phenergan can be purchased safely from our online pharmacy in Hong Kong. Our service offers several advantages for patients who face limited pharmacy stock or high out‑of‑pocket costs:

• Affordable pricing – We source the medication close to manufacturer cost, passing savings directly to the consumer.
• Verified quality – All batches are obtained from licensed overseas suppliers that meet international Good Manufacturing Practice (GMP) standards.
• Guaranteed delivery – Discreet packaging is shipped via express courier (typically 7 days) or regular airmail (approximately 3 weeks), with tracking available for every order.
• Online‑only accessibility – Our pharmacy broker model works with accredited international pharmacies, enabling customers to obtain medications that may not be stocked locally.

Patients receive a confidential, privacy‑focused experience while gaining reliable access to a clinically proven antihistamine.

FAQ

• Can Phenergan be taken with other antihistamines?
  Combining Phenergan with another antihistamine can increase the risk of excessive sedation and anticholinergic side effects. Generally, it is not recommended unless directed by a specialist who monitors the interaction closely.

• Does Phenergan require refrigeration?
  No. Phenergan tablets and oral solution should be stored at room temperature, away from direct sunlight and moisture. Refrigeration is unnecessary and may affect tablet integrity.

• What does the Phenergan tablet look like?
  The standard 25 mg tablet is round, white, and may have a film coating with imprint “P 25”. In some markets, the tablet may be pinkish or have a different imprint depending on the manufacturer.

• Are there differences between US and Asian formulations of promethazine?
  The active ingredient and dosage strength are identical, but inactive excipients such as dyes, binders, or preservatives may vary. These differences rarely affect clinical efficacy but could influence tolerability in patients with specific allergies.

• Can Phenergan be imported for personal use into Hong Kong?
  Personal import of a three‑month supply for self‑use is permitted under Hong Kong customs regulations, provided the medication is for a legitimate medical purpose and is accompanied by a copy of the prescription.

• Is it safe to travel internationally with Phenergan?
  Yes, but keep the medication in its original packaging with a copy of the prescription or a physician’s letter. Avoid carrying it in checked luggage to reduce the risk of loss or temperature extremes.

• Does Phenergan affect drug testing for employment?
  Promethazine is not a controlled substance and does not appear on standard drug‑screen panels. However, some specialized tests could detect antihistamines if specifically requested.

• What is the history of promethazine’s development?
  Promethazine was first synthesized in 1945 by the pharmaceutical company Schering AG as part of a series of phenothiazine derivatives. It was subsequently introduced as an antihistamine and later found to possess anti‑emetic and sedative properties.

• How does Phenergan compare with newer second‑generation antihistamines?
  Second‑generation antihistamines (e.g., cetirizine, loratadine) cause less sedation because they do not cross the blood–brain barrier as readily. Phenergan is more suitable when a sedative effect is desired, such as for pre‑operative anxiety or severe motion sickness.

• What are the inert ingredients in the oral solution?
  The syrup typically contains sucrose, sorbitol, flavoring agents, and a preservative such as methylparaben. Exact composition may differ by manufacturer, and patients with sugar intolerance should review the label carefully.

Glossary

Antihistamine

A drug that blocks the action of histamine at H₁ receptors, reducing allergic symptoms such as itching, swelling, and redness.

Anticholinergic

A property of a medication that inhibits the neurotransmitter acetylcholine, leading to effects like dry mouth, blurred vision, and reduced gastrointestinal motility.

First‑generation H₁‑receptor antagonist

An older class of antihistamines that readily enter the central nervous system, often causing sedation and other central side effects.

Bioavailability

The proportion of an administered dose that reaches systemic circulation in an active form.

⚠️ Disclaimer

The information provided about Phenergan is for general knowledge only. It does not replace professional medical consultation. All treatment decisions should be made under the supervision of a qualified healthcare provider. We assume all readers are responsible adults capable of making informed decisions about their health. Our online pharmacy offers access to Phenergan for individuals who may have limited availability through traditional pharmacies, prescription‑based insurance schemes, or who are seeking affordable generic alternatives. Always consult your doctor before starting, changing, or discontinuing any medication.