Introduction to DILANTIN-125
DILANTIN-125, the brand name for the oral suspension formulation of phenytoin, is a widely used antiepileptic medication. It is indicated for the treatment of tonic-clonic (grand mal) and psychomotor (temporal lobe) seizures. Here, we will delve into the clinical trials, market analysis, and future projections for this drug.
Clinical Trials and Safety Profile
Historical Context and Approval
DILANTIN-125 was first approved by the FDA in 1953, and since then, it has undergone numerous clinical trials and safety evaluations. The drug has been extensively studied in various patient populations, including adults and children[4].
Safety and Adverse Reactions
Clinical trials and post-marketing surveillance have highlighted several key safety concerns associated with DILANTIN-125. These include serious dermatologic reactions such as Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), which can be fatal. Patients, especially those of Asian ancestry with the HLA-B*1502 allele, are at a higher risk of developing these conditions[1][3][4].
Other significant adverse reactions include hematopoietic complications like thrombocytopenia, leukopenia, and agranulocytosis, as well as the potential for suicidal thoughts or behavior. Monitoring for these side effects is crucial, and dose adjustments or discontinuation may be necessary based on patient response[3][4].
Serum Level Monitoring
Clinical trials have emphasized the importance of serum level monitoring to achieve optimal therapeutic levels of phenytoin. The clinically effective serum total concentration is typically between 10 and 20 mcg/mL, with peak levels occurring 1½–3 hours after administration. This monitoring helps in managing the wide interpatient variability in phenytoin serum levels and in adjusting dosages accordingly[1][3][4].
Market Analysis
Market Presence and Generic Availability
DILANTIN-125 is available in the market as an oral suspension with a strength of 125 mg/5 mL. The brand is owned by Viatris, and generic versions are also available, which has impacted the market dynamics. The generic availability has increased accessibility and reduced costs for patients, making the drug more competitive in the antiepileptic market[2].
Market Trends
The antiepileptic drug market is growing due to an increasing prevalence of epilepsy and the development of new therapeutic options. However, DILANTIN-125 faces competition from newer antiepileptic drugs that may have better safety profiles or more convenient dosing regimens. Despite this, its long-standing presence and established efficacy ensure it remains a significant player in the market.
Patient Population and Demographics
DILANTIN-125 is prescribed to a diverse patient population, including children and adults. The pediatric dosage is tailored to the child's weight, with adjustments made as necessary to achieve therapeutic levels. In adults, the starting dose is typically 5 mL three times daily, with adjustments based on serum level monitoring[4].
Market Projections
Future Demand
The demand for DILANTIN-125 is expected to remain stable due to its established use in managing epilepsy. However, the market share may be influenced by the introduction of newer antiepileptic drugs and changes in prescribing practices. The growing awareness of epilepsy and the need for effective management will continue to drive the demand for antiepileptic medications, including DILANTIN-125.
Competitive Landscape
The competitive landscape in the antiepileptic drug market is dynamic, with several drugs available for different types of seizures. Newer drugs like levetiracetam and lacosamide may offer advantages in terms of safety and tolerability, but DILANTIN-125's long history of use and cost-effectiveness will help it maintain its market position.
Regulatory Environment
Regulatory updates and changes in labeling can impact the market for DILANTIN-125. For instance, updates to the safety information, such as the addition of hypersensitivity to inactive ingredients, can influence prescribing decisions. Continuous monitoring and compliance with regulatory requirements will be crucial for maintaining market presence[1].
Special Considerations
Dosing in Special Populations
DILANTIN-125 requires careful dosing adjustments in special populations, including patients with renal or hepatic disease, elderly patients, and pregnant women. For example, decreased serum concentrations of phenytoin may occur during pregnancy due to altered pharmacokinetics, necessitating periodic monitoring and dose adjustments[4][5].
Switching Between Formulations
Switching between different formulations of phenytoin (e.g., from the free acid form to the sodium salt form) requires careful consideration and serum level monitoring due to differences in drug content and bioavailability[4].
Key Takeaways
- Established Efficacy: DILANTIN-125 has a long history of effective use in managing tonic-clonic and psychomotor seizures.
- Safety Concerns: The drug is associated with serious side effects, including SJS/TEN and hematopoietic complications, necessitating careful monitoring.
- Market Competition: The antiepileptic drug market is competitive, with newer drugs offering potential advantages in safety and tolerability.
- Regulatory Compliance: Continuous updates to safety information and regulatory compliance are essential for maintaining market presence.
- Special Populations: Careful dosing adjustments are required in special populations, including pregnant women and patients with renal or hepatic disease.
FAQs
What are the primary indications for DILANTIN-125?
DILANTIN-125 is indicated for the treatment of tonic-clonic (grand mal) and psychomotor (temporal lobe) seizures[4].
What are the common side effects of DILANTIN-125?
Common side effects include serious dermatologic reactions like SJS/TEN, hematopoietic complications, and the potential for suicidal thoughts or behavior[3][4].
How is the dosage of DILANTIN-125 adjusted in pediatric patients?
The recommended starting dosage for pediatric patients is 5 mg/kg/day in two or three equally divided doses, with subsequent dosage individualized to a maximum of 300 mg daily[4].
What is the significance of serum level monitoring for DILANTIN-125?
Serum level monitoring is crucial to achieve optimal therapeutic levels (10-20 mcg/mL) and to manage interpatient variability in phenytoin serum levels[1][3][4].
How does pregnancy affect the dosing of DILANTIN-125?
During pregnancy, decreased serum concentrations of phenytoin may occur due to altered pharmacokinetics, necessitating periodic monitoring and dose adjustments[4][5].
Sources
- FDA Approval Package for NDA 08-762/S-039 - accessdata.fda.gov
- Generic Dilantin Availability - Drugs.com
- Dilantin-125 FDA Approved Labeling Text - accessdata.fda.gov
- Dilantin-125: Package Insert / Prescribing Information - Drugs.com
- Phenytoin Oral Suspension USP - Pfizer
