Emetrex Injection: A Guide to Uses, Dosage, and Side Effects

Disclaimer: This document is intended for educational purposes only. It does not replace professional medical advice. Always use Emetrex only under the prescription and supervision of a licensed physician.

Emetrex® (Cyclizine Lactate) Injection

Summary

Emetrex® (Cyclizine Lactate) is an injectable antiemetic medication used to control nausea and vomiting when the oral route is not feasible. As a histamine H1 receptor antagonist, it is effective against motion sickness, vertigo, and postoperative nausea. Its anticholinergic properties require caution in certain patient groups, such as the elderly and those with glaucoma or prostatic hypertrophy.

Manufacturer

Manufactured by Global Pharmaceutical Industries for Amoun Pharmaceutical Co., Obour City, Cairo, Egypt.

Category & Active Ingredient

• Category: Antiemetic, Antihistamine (H1 Receptor Antagonist, Piperazine derivative).
• Active Ingredient: Cyclizine Lactate.

Available Forms & Strengths in Egypt

Emetrex is available in the following forms:

• Ampoules for Injection: 50 mg / 1 ml (for Intramuscular or slow Intravenous use).
• Tablets (Oral): A combination product containing Cyclizine and Vitamin B6 is also available.

Properties and Mechanism of Action

Cyclizine is a piperazine-derivative antihistamine that exerts its effects by acting as a competitive antagonist at histamine H1 receptors. Its mechanism includes:

• Antiemetic Effect: It blocks H1 receptors in the vomiting center of the brainstem and reduces nerve transmission from the vestibular apparatus to the vomiting center.
• Anticholinergic Effect: It possesses anticholinergic (muscarinic) properties, which contribute to its anti-sickness effect and also cause side effects like dry mouth and blurred vision.
• Antivertigo Effect: It reduces the sensitivity of the labyrinthine system in the inner ear, making it effective for vertigo and motion sickness.

Pharmacokinetics

• Onset of Action: Approximately 30-60 minutes after injection.
• Duration of Action: 4-6 hours.
• Metabolism: Primarily metabolized in the liver.
• Excretion: Excreted in the urine, mainly as metabolites.
• Half-life: Around 14-16 hours.

Indications

Emetrex injection is indicated for the prophylaxis and treatment of nausea and vomiting in various conditions, especially when the oral route is unavailable or impractical:

• Postoperative Nausea and Vomiting (PONV).
* Nausea and vomiting associated with drug administration (e.g., opioids, chemotherapy).
• Motion sickness.
• Vestibular disorders such as Ménière’s disease and labyrinthitis.
• Radiation sickness.
• Severe nausea and vomiting during pregnancy (hyperemesis gravidarum), under strict medical supervision.

Dosage and Administration

Route: For Intramuscular (IM) or slow Intravenous (IV) injection.

• Adults and children over 12 years: 50 mg (1 ampoule) up to three times daily.
• Children 6-12 years: 25 mg (0.5 ml) up to three times daily.
• Children under 6 years: Not recommended.

Important: For IV administration, the injection should be given slowly over 1-2 minutes. Do not mix Emetrex with other drugs in the same syringe.

Contraindications

Emetrex should not be used in:

• Patients with known hypersensitivity to cyclizine or other components.
• Neonates and children under 6 years of age.

Warnings & Precautions

Use with caution in the following conditions:

• Closed-angle Glaucoma: Anticholinergic effects can increase intraocular pressure.
• Prostatic Hypertrophy or Urinary Retention: May worsen urinary retention.
• Severe Heart Failure: May cause a fall in cardiac output.
• Hepatic Impairment: Use with caution as the drug is metabolized in the liver.
• Elderly Patients: More susceptible to anticholinergic side effects like confusion, disorientation, and hallucinations.
• Driving and Operating Machinery: May cause drowsiness. Patients should be warned not to drive or operate heavy machinery until they know how the medication affects them.

Drug Interactions

• CNS Depressants: Additive sedative effects when taken with alcohol, opioids, barbiturates, or other sedatives.
• Anticholinergic Drugs: Increased risk of anticholinergic side effects (e.g., dry mouth, constipation, blurred vision) when used with drugs like tricyclic antidepressants or atropine.
• Ototoxic Drugs: May mask the warning signs of damage caused by ototoxic drugs (e.g., aminoglycoside antibiotics).

Side Effects

• Common: Drowsiness, dizziness, dry mouth, blurred vision, headache.
• Uncommon: Tachycardia (rapid heart rate), constipation, urinary retention.
• Rare: Confusion, hallucinations (especially in the elderly or with high doses), injection site reactions.

Use in Pregnancy & Lactation

• Pregnancy: While commonly used for nausea and vomiting in pregnancy, it should only be administered under the guidance of a physician when the benefits are deemed to outweigh the potential risks.
• Lactation: Cyclizine is excreted in breast milk. Caution is advised, and a decision should be made to either stop breastfeeding or discontinue the drug.

Overdose

• Symptoms: Characterized by severe anticholinergic effects, including hyperthermia, drowsiness, confusion, hallucinations, ataxia, convulsions, and coma.
• Management: Treatment is symptomatic and supportive. It may include activated charcoal, monitoring of vital signs, and management of convulsions with diazepam.

Storage

• Store below 30°C.
• Protect from light.
• Keep out of reach of children.

Presentation / Package

• Box containing 2 ampoules of 1 ml (50 mg/ml).

Frequently Asked Questions (FAQ)

Q1: How quickly does Emetrex injection work?

A: It typically starts working within 30 to 60 minutes after an intramuscular injection.

Q2: Can Emetrex injection be self-administered at home?

A: No. Emetrex is a prescription medication that should only be administered by a qualified healthcare professional.

Q3: Does Emetrex help with anxiety-related nausea?

A: While it treats the symptom of nausea, it does not treat the underlying anxiety. Its sedative effect might provide some temporary relief, but it is not an anti-anxiety medication.

Q4: Why is it not recommended for children under 6?

A: The safety and efficacy of cyclizine have not been adequately established in this age group, and young children are more susceptible to side effects.

References

1. British National Formulary (BNF), "Cyclizine".
2. Martindale: The Complete Drug Reference.
3. World Health Organization (WHO) Model Formulary.
4. Amoun Pharmaceutical Co., Official Product Leaflet.