SER-A-GEN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SER-A-GEN (SER-A-GEN).
SER-A-GEN is a serotonin receptor agonist that selectively activates 5-HT1A and 5-HT2A receptors, modulating neurotransmitter release in the central nervous system.
| Metabolism | Hepatic via CYP3A4 and CYP2D6 isoenzymes; undergoes glucuronidation to inactive metabolites. |
| Excretion | Primarily renal: 70% unchanged drug; 20% as glucuronide conjugate; <5% fecal. |
| Half-life | 8 ± 2 hours; prolonged to 20-30 hours in severe renal impairment (CrCl <30 mL/min). |
| Protein binding | 92% primarily to albumin; also binds α1-acid glycoprotein. |
| Volume of Distribution | 0.45 ± 0.15 L/kg; indicates distribution predominantly into extracellular fluid. |
| Bioavailability | Oral: 65-75% with first-pass metabolism; intramuscular: 100%. |
| Onset of Action | Intravenous: 2-5 minutes; Oral: 30-45 minutes. |
| Duration of Action | Intravenous: 4-6 hours; Oral: 6-8 hours, extended-release formulation up to 12 hours. |
500 mg orally once daily.
| Dosage form | TABLET |
| Renal impairment | GFR 30-50 mL/min: 250 mg once daily; GFR <30 mL/min: 250 mg every other day; dialysis: 250 mg three times weekly after dialysis. |
| Liver impairment | Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50%; Child-Pugh Class C: use not recommended. |
| Pediatric use | Weight ≥10 kg: 10 mg/kg orally once daily; maximum 500 mg daily. |
| Geriatric use | No specific dose adjustment; monitor renal function and reduce dose per renal adjustment if CrCl <50 mL/min. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for SER-A-GEN (SER-A-GEN).
| Breastfeeding | Excreted into breast milk in low concentrations; M/P ratio 0.25. Potential for infant sedation and poor feeding. Consider alternative therapy or monitor infant for lethargy and weight gain. |
| Teratogenic Risk | First trimester: Associated with neural tube defects (NTDs), cardiovascular malformations, and oral clefts. Second and third trimesters: Risk for fetal growth restriction, preterm birth, and neonatal respiratory depression. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
Concurrent use of MAOIs; hypersensitivity to SER-A-GEN; severe hepatic impairment (Child-Pugh C).
| Precautions | Serotonin syndrome risk when co-administered with other serotonergic drugs; QT prolongation at high doses; hepatic impairment requires dose adjustment; discontinuation syndrome upon abrupt cessation. |
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| Monitor maternal blood pressure, hepatic function, and complete blood count. Fetal surveillance with ultrasound for growth, amniotic fluid index, and non-stress test starting at 32 weeks. |
| Fertility Effects | May reduce ovarian reserve and cause menstrual irregularities; reversible upon discontinuation. No evidence of permanent infertility. |