Prostaglandins and Prostaglandin Analogs
Key Points
- Prostaglandins are lipid compounds derived from arachidonic acid via cyclooxygenase pathway
- Act as local hormones with diverse physiological effects
- Critical in maintaining patent ductus arteriosus in ductal-dependent congenital heart disease
- Essential roles in inflammation, fever, pain, and vascular tone
Chemical Classification
- PGE1 (Alprostadil)
- PGE2 (Dinoprostone)
- PGI2 (Prostacyclin)
- Synthetic analogs (Misoprostol, Latanoprost)
Mechanism of Action
Molecular Basis
- Bind to specific G-protein coupled receptors (EP1-4, IP, FP)
- Activate adenylyl cyclase → ↑cAMP
- Modulate calcium channels
- Influence smooth muscle tone
Physiological Effects
- Vasodilation (especially PGE1, PGI2)
- Platelet aggregation inhibition
- Bronchodilation (PGE2)
- Gastric mucosa protection
- Uterine contraction
Clinical Applications in Pediatrics
Cardiovascular
- Maintaining ductal patency in cyanotic congenital heart disease
- Bridge to surgery in ductal-dependent lesions
- Treatment of pulmonary hypertension
Gastrointestinal
- Gastric cytoprotection in high-risk patients
- Prevention of NSAID-induced ulcers
Ophthalmology
- Treatment of congenital glaucoma
- Management of elevated intraocular pressure
Specific Agents and Dosing
Alprostadil (PGE1)
- Initial dose: 0.05-0.1 mcg/kg/min IV
- Maintenance: 0.01-0.4 mcg/kg/min
- Route: Continuous IV infusion
- Major use: Ductal-dependent congenital heart disease
Misoprostol
- Pediatric dose: 2-4 mcg/kg/day divided q6h
- Route: Oral
- Major use: Gastric protection
Latanoprost
- Pediatric dose: One drop in affected eye(s) daily
- Route: Ophthalmic
- Major use: Pediatric glaucoma
Special Considerations and Monitoring
Adverse Effects
- Apnea (especially in neonates)
- Fever
- Cutaneous flushing
- Hypotension
- Diarrhea
Monitoring Parameters
- Continuous cardiac monitoring
- Frequent blood pressure measurements
- Respiratory rate and oxygen saturation
- Temperature
- Blood gases in critical patients
Contraindications
- Respiratory depression
- Severe hypotension
- Active bleeding
