Diphenhydramine + Dextromethorphan + Levomenthol

Generic Details

Generic Name

Diphenhydramine-Dextromethorphan-Levomenthol

Other Names

  • Diphenhydramine-DM-Levomenthol

Drug Class

  • Antihistamine
  • Antitussive
  • Topical Analgesic

Chemical Formula

C17H21NO.C18H25NO.H2O

Molecular Weight

306.39 g/mol (diphenhydramine) + 278.38 g/mol (dextromethorphan) + 155.25 g/mol (levomenthol)

Mechanism of Action

  • Diphenhydramine - Antagonizes the effects of histamine at H1-receptor sites
  • Dextromethorphan - Suppresses the cough reflex in the medulla oblongata
  • Levomenthol - Acts as a topical analgesic and mild local anesthetic

Indications

  • Common cold
  • Cough
  • Allergic rhinitis
  • Mild to moderate pain
  • Topical pain relief

Common Dosage Forms

  • Tablet
  • Oral syrup
  • Topical cream/gel

Typical Dosage

  • Diphenhydramine 25-50mg
  • Dextromethorphan 10-20mg
  • Levomenthol cream applied topically as needed

Pediatric Dosage

  • Doses adjusted based on weight and age for children

Geriatric Dosage

  • Lower starting doses may be required in the elderly

Side Effects

  • Drowsiness
  • Dizziness
  • Dry mouth
  • Constipation
  • Nausea
  • Skin irritation (topical use)

Contraindications

  • Hypersensitivity to any component
  • Narrow-angle glaucoma
  • Severe liver disease

Pregnancy Category

  • Diphenhydramine - Category B
  • Dextromethorphan - Category C
  • Levomenthol - Not well studied

Lactation Safety

  • Diphenhydramine and Dextromethorphan excreted in breast milk, caution advised

Drug Interactions

  • Monoamine oxidase inhibitors (MAOIs)
  • Sedatives
  • Alcohol

Overdose Symptoms

  • Severe drowsiness
  • Confusion
  • Rapid heart rate
  • Seizures

Antidote for Overdose

  • Supportive care and symptomatic treatment

Storage Conditions

  • Store at room temperature away from moisture and heat

Pharmacokinetics

  • Absorption: Well absorbed orally
  • Distribution: Widely distributed in the body, including the CNS
  • Metabolism: Metabolized in the liver
  • Excretion: Excreted in urine

Precautions

  • Use with caution in patients with asthma or COPD
  • Avoid driving or operating machinery due to drowsiness
  • Avoid use in children under 2 years old

Warnings

  • Do not exceed recommended doses
  • Avoid alcohol consumption while using this medication

Others