Usage
Seratrodast is prescribed for the prophylactic management of mild to moderate bronchial asthma. It belongs to the pharmacological class of thromboxane A2 receptor antagonists. Its mechanism of action involves selectively blocking the thromboxane A2 receptor, thus inhibiting bronchoconstriction, airway inflammation, and mucus production.
Alternate Names
While “Seratrodast” is the generic name, brand names include Seretra, Bronica (Japan), Changnuo, Mai Xu Jia, and Quan Kang Nuo (China).
How It Works
Pharmacodynamics: Seratrodast antagonizes the thromboxane A2 receptor, preventing bronchoconstriction, airway inflammation, and mucus production associated with asthma. It inhibits the effects of thromboxane A2, a potent bronchoconstrictor and vasoconstrictor produced by platelets. This action helps reduce airway hyperresponsiveness and improves lung function in asthmatic patients.
Pharmacokinetics:
- Absorption: Seratrodast is rapidly absorbed after oral administration, reaching peak plasma concentrations within 2.4 to 4 hours. The absorption is dose-dependent.
- Metabolism: Primarily metabolized in the liver by cytochrome P450 (CYP) isoenzymes, specifically CYP2D6 and 3A4, to 5-methylhydroxyseratrodast, 4-hydroxyseratrodast, and glucuronide conjugates. It also undergoes enterohepatic recycling.
- Elimination: Seratrodast is eliminated through both renal and hepatic pathways. Approximately 20% of the dose is excreted unchanged in urine, while the rest is eliminated as metabolites. The elimination half-life is around 20-36 hours, reaching steady-state plasma concentration within 7 days.
Mode of Action: Seratrodast competitively binds to the thromboxane A2 receptor, preventing the binding of thromboxane A2 and inhibiting its downstream effects like smooth muscle contraction and platelet aggregation.
Dosage
Standard Dosage
Adults:
The recommended dose is 80 mg once daily, taken orally. The maximum dose is 320 mg per day.
Children:
The safety and efficacy of Seratrodast have not been established in children under 18 years old, therefore it is not recommended for pediatric use.
Special Cases:
- Elderly Patients: Start with a lower dose of 40 mg/day and titrate as needed. Due to age-related decline in renal and hepatic function, monitor closely for adverse events.
- Patients with Renal Impairment: Dose adjustments may be necessary. Close monitoring is recommended.
- Patients with Hepatic Dysfunction: Contraindicated in patients with hepatic failure. Use with caution in mild to moderate hepatic impairment, starting with a lower dose and closely monitoring liver function tests.
- Patients with Comorbid Conditions: Use with caution in patients with cardiovascular disease, diabetes, or other relevant conditions, considering potential drug interactions and side effects.
Clinical Use Cases
Seratrodast’s primary use is in the prophylactic management of asthma. It is not indicated for acute asthma attacks. Dosage adjustments are not typically made for intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. Use a short-acting bronchodilator for acute exacerbations.
Dosage Adjustments
Dose modifications should be considered for elderly patients, and those with renal or hepatic impairment. Therapeutic drug monitoring and dose adjustments based on clinical response and tolerability may be needed.
Side Effects
Common Side Effects
- Rash
- Itching
- Nausea
- Abdominal pain
- Headache
- Elevated liver enzymes
- Diarrhea
- Dry mouth
- Dizziness
- Drowsiness
- Palpitations
- Malaise
Rare but Serious Side Effects
- Thrombocytopenia
- Epistaxis (nosebleeds)
- Bleeding tendency
- Hepatic dysfunction (rarely severe)
- Allergic reactions (angioedema, urticaria)
Long-Term Effects
Long-term effects are not well-established but may include chronic liver abnormalities if not monitored carefully.
Adverse Drug Reactions (ADR)
Severe allergic reactions or significant hepatic dysfunction require immediate discontinuation and supportive care.
Contraindications
- Hypersensitivity to Seratrodast
- Severe hepatic impairment or hepatic failure
Drug Interactions
- CYP450 Interactions: Seratrodast is metabolized by CYP2D6 and 3A4. Concomitant use with CYP inhibitors (ketoconazole, erythromycin) may increase Seratrodast levels. CYP inducers (rifampin, phenytoin) may decrease Seratrodast levels.
- Other Interactions: Use with caution with anti-inflammatory analgesics, cephalosporin antibiotics, and drugs that cause hemolytic anemia. Aspirin may increase unbound Seratrodast concentration. Avoid alcohol due to increased drowsiness.
- Other Medications: Consult drug interaction resources for potential interactions with other commonly prescribed medications, OTC drugs, and supplements.
Pregnancy and Breastfeeding
Pregnancy Safety: No adequate and well-controlled studies in pregnant women exist. Use only if the potential benefit outweighs the potential risk to the fetus.
Breastfeeding: Avoid Seratrodast during breastfeeding due to potential excretion in breast milk and unknown effects on the infant.
Drug Profile Summary
- Mechanism of Action: Thromboxane A2 receptor antagonist.
- Side Effects: Rash, itching, nausea, abdominal pain, headache, elevated liver enzymes. Rarely: Thrombocytopenia, bleeding.
- Contraindications: Hepatic failure, hypersensitivity.
- Drug Interactions: CYP2D6 and 3A4 inhibitors/inducers, aspirin, certain antibiotics.
- Pregnancy & Breastfeeding: Use with caution in pregnancy only if benefits outweigh risks. Avoid during breastfeeding.
- Dosage: 80mg once daily (adults), 40 mg initially for elderly. Not recommended for children.
- Monitoring Parameters: Liver function tests, complete blood count.
Popular Combinations
Seratrodast is not commonly used in fixed-dose combinations. Its use with other asthma medications (inhaled corticosteroids, bronchodilators) should be individualized based on patient needs.
Precautions
- General Precautions: Assess liver function before and during treatment. Monitor for bleeding and allergic reactions.
- Specific Populations: Use with caution in pregnancy and avoid during breastfeeding. Not recommended for children. Reduce initial dose in elderly patients.
FAQs
Q1: What is the recommended dosage for Seratrodast?
A: 80 mg once daily for adults. 40 mg initially for elderly patients. Not recommended for children under 18.
Q2: How does Seratrodast work in asthma?
A: It blocks the thromboxane A2 receptor, preventing bronchoconstriction and inflammation.
Q3: What are the common side effects?
A: Rash, itching, nausea, abdominal pain, headache, and elevated liver enzymes.
Q4: Can Seratrodast be used during pregnancy?
A: Only if the potential benefit justifies the potential risk to the fetus. No adequate studies in pregnant women are available.
Q5: Is Seratrodast safe for patients with liver problems?
A: No. It’s contraindicated in patients with hepatic failure and should be used cautiously in patients with mild to moderate hepatic impairment.
Q6: Does Seratrodast interact with other medications?
A: Yes. It interacts with CYP2D6 and 3A4 inhibitors/inducers, aspirin, and some antibiotics. Consult drug interaction resources for a comprehensive list.
Q7: Can I take Seratrodast with alcohol?
A: Alcohol should be avoided as it may worsen side effects like drowsiness.
Q8: Is Seratrodast used to treat acute asthma attacks?
A: No. It’s for prophylactic management of chronic asthma, not acute exacerbations. A rescue inhaler should be used for acute attacks.
Q9: What should I monitor while a patient is taking Seratrodast?
A: Monitor liver function tests and complete blood counts periodically, especially in the initial phase of treatment. Also, closely observe for any signs of bleeding tendencies or allergic reactions.
