Aromatase Inhibitors in Pediatric Medicine
Key Points
- Selective inhibitors of estrogen biosynthesis
- Primary uses: Growth disorders, precocious puberty, gynecomastia
- Most evidence with third-generation AIs
- Requires careful monitoring of bone health
Mechanism of Action
- Inhibition of aromatase enzyme
- Blocks conversion of androgens to estrogens
- Reduces estrogen biosynthesis
- Increases testosterone availability
- Impact on Growth Plate
- Delays epiphyseal fusion
- Potentially increases final height
Types and Pharmacology
Available Medications
| Generation |
Drug |
Half-life |
Potency |
| Third |
Letrozole |
48 hours |
Highest |
| Third |
Anastrozole |
41 hours |
High |
| Second |
Exemestane |
27 hours |
Moderate |
Dosing Guidelines
| Medication |
Pediatric Dose |
Frequency |
Administration |
| Letrozole |
2.5 mg |
Once daily |
With/without food |
| Anastrozole |
1 mg |
Once daily |
With/without food |
| Exemestane |
25 mg |
Once daily |
After meals |
Clinical Indications
Primary Indications
- Growth Enhancement
- Constitutional delay of growth and puberty
- Idiopathic short stature
- Growth hormone deficiency
- Pubertal Disorders
- Peripheral precocious puberty
- McCune-Albright syndrome
- Pubertal gynecomastia
- Endocrine Disorders
- Aromatase excess syndrome
- Testotoxicosis
Specific Conditions Management
| Condition |
Preferred AI |
Duration |
Expected Outcomes |
| McCune-Albright |
Letrozole |
12-24 months |
↓ Bone age advancement |
| Gynecomastia |
Anastrozole |
3-6 months |
Breast tissue reduction |
| Growth Enhancement |
Letrozole |
12-36 months |
↑ Predicted adult height |
Treatment Management
Pre-treatment Assessment
- Required Baseline Studies
- Bone age radiograph
- Growth velocity
- Pubertal staging
- Bone density (DXA)
- Laboratory Evaluation
- Estradiol/Testosterone
- LH/FSH
- Bone markers
- Liver function tests
Monitoring Protocol
| Parameter |
Frequency |
Action Points |
| Height/Growth Rate |
Every 3-4 months |
Deviation from expected |
| Bone Age |
Every 6-12 months |
Rapid advancement |
| DXA Scan |
Annually |
Z-score < -2.0 |
Safety & Monitoring
Adverse Effects
- Common Effects
- Headache
- Hot flushes
- Arthralgia
- Fatigue
- Serious Concerns
- Vertebral deformities
- Decreased bone mineral density
- Growth plate abnormalities
- Cognitive effects
Risk Management
- Bone Health Protection
- Adequate calcium intake
- Vitamin D supplementation
- Regular physical activity
- Growth Monitoring
- Regular height measurements
- Growth velocity calculation
- Bone age assessment
- Endocrine Function
- Sex hormone levels
- Growth factors
- Metabolic parameters
Special Considerations
| Population |
Concerns |
Recommendations |
| Adolescents |
Bone mineralization |
Regular DXA monitoring |
| Pre-pubertal |
Growth potential |
Careful growth tracking |
| Long-term use |
Skeletal maturation |
Annual bone age X-rays |
Further Reading
