Avomine

• Allergic Conditions:
  Treatment of allergic rhinitis, urticaria, angioedema, and other allergic reactions.
• Motion Sickness:
  Prevention and treatment of nausea, vomiting, and dizziness associated with motion sickness.
• Nausea and Vomiting:
  Management of nausea and vomiting related to surgery, medications, or other causes.
• Sedation:
  Preoperative and postoperative sedation; adjunct to analgesics.
• Respiratory Conditions:
  Adjunctive therapy in bronchial asthma and chronic obstructive pulmonary disease (COPD) to relieve bronchospasm and associated symptoms.
• Cough and Cold:
  Symptomatic relief of cough and upper respiratory tract symptoms.

Route: Oral

Adults:

• 1 to 2 tablets (each containing promethazine 25 mg and theophylline 100 mg) two to three times daily.
• Dosage may be adjusted according to clinical response, typically not exceeding 6 tablets per day.

Pediatrics:

• Use with caution. Dose individualized based on body weight and clinical condition.
• Generally, half the adult dose under close medical supervision.
• Contraindicated in children under 2 years.

Elderly:

• Start at the lowest effective dose.
• Monitor for sedation and cardiovascular side effects.

Renal/Hepatic Impairment:

• Use with caution. Monitor for toxicity due to impaired metabolism and clearance.
• Therapeutic drug monitoring of theophylline is recommended during prolonged therapy.

Promethazine is a first-generation H1 receptor antagonist that blocks histamine at H1 receptors, reducing allergic symptoms and exerting sedative and antiemetic effects by antagonizing histamine receptors in the central nervous system and chemoreceptor trigger zone. Theoclate, a theophylline derivative, is a methylxanthine bronchodilator that inhibits phosphodiesterase, increasing intracellular cyclic AMP, leading to relaxation of bronchial smooth muscle and bronchodilation. Together, they relieve allergy symptoms, nausea, and bronchospasm.

• Absorption: Both components are well absorbed orally. Promethazine acts within 20–60 minutes; theophylline within 1–2 hours.
• Distribution: Promethazine is highly protein-bound (~90%) and crosses the blood-brain barrier; theophylline distributes widely, including lung tissue.
• Metabolism: Promethazine metabolized hepatically via CYP2D6 and CYP2B6; theophylline metabolized mainly via CYP1A2.
• Elimination: Both are primarily excreted via the kidneys as metabolites. Promethazine half-life is 10–19 hours; theophylline half-life varies from 3 to 7 hours depending on individual factors.

• Pregnancy: FDA Category C. Use only if benefits justify potential risk; animal data show some adverse effects, but human data are limited.
• Lactation: Both components are excreted in breast milk. Caution advised due to possible sedation or irritability in infants.

• Combination drug: First-generation H1 antihistamine (promethazine) and methylxanthine bronchodilator (theophylline derivative).

• Hypersensitivity to promethazine, theophylline, or excipients.
• Severe hepatic or renal impairment (use with caution).
• Children under 2 years old.
• Concurrent use of monoamine oxidase inhibitors (MAOIs).
• History of seizure disorders or significant cardiac arrhythmias.

• Risk of sedation and respiratory depression, especially in children and elderly.
• Narrow therapeutic index of theophylline requires monitoring to avoid toxicity.
• Avoid abrupt discontinuation to prevent bronchospasm.
• Use caution in patients with cardiovascular disease due to arrhythmia risk.
• Monitor liver and kidney function during extended therapy.

• Common: Drowsiness, dizziness, dry mouth, nausea, palpitations.
• Serious: Theophylline toxicity (arrhythmias, seizures), severe sedation, allergic reactions, extrapyramidal symptoms (rare).
• Rare: Neurotoxicity, severe bronchospasm.

• CNS depressants (alcohol, opioids, benzodiazepines): additive sedation and respiratory depression.
• CYP1A2 inhibitors (e.g., fluoroquinolones) increase theophylline levels; inducers (e.g., smoking) decrease levels.
• MAO inhibitors: contraindicated.
• Beta-blockers may antagonize theophylline’s bronchodilation.
• Other anticholinergic drugs may potentiate promethazine’s anticholinergic effects.

• Enhanced warnings on pediatric use, emphasizing risks of sedation and respiratory depression.
• Recommendations for regular monitoring of theophylline serum levels.
• Updated safety profiles for pregnancy and breastfeeding.
• Regulatory advisories cautioning against use in children under 2 years.

• Store at 20°C to 25°C (68°F to 77°F).
• Protect from moisture and light.
• Keep tightly closed in original container.
• Do not freeze.
• Keep out of reach of children.