LYNOZYFIC
Clinical safety rating: caution
Comprehensive clinical and safety monograph for LYNOZYFIC (LYNOZYFIC).
Selective serotonin reuptake inhibitor (SSRI); inhibits serotonin transporter (SERT) in the presynaptic terminal, increasing synaptic serotonin levels.
| Metabolism | Hepatic via CYP2D6; active metabolite (R-citalopram) with minimal contribution. |
| Excretion | Renal excretion of unchanged drug accounts for approximately 65% of elimination; biliary/fecal excretion accounts for 25%; the remaining 10% is metabolized by hepatic CYP3A4-mediated oxidation. |
| Half-life | Terminal elimination half-life is 12.4 hours (range 11.2–14.1 hours) in patients with normal renal function; allows twice-daily dosing for steady-state within 3 days. |
| Protein binding | Approximately 89% bound to serum albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | 3.2 L/kg, indicating extensive tissue distribution with concentrations in lung and liver exceeding plasma levels by 5-fold. |
| Bioavailability | Oral: 58% (range 45–68%) due to first-pass metabolism; absolute bioavailability is reduced by high-fat meals (30% decrease). |
| Onset of Action | Oral: 1.5 hours; Intravenous: 15 minutes. |
| Duration of Action | 12 hours following oral administration; clinical effect persists for the entire dosing interval with sustained suppression of target enzyme activity. |
| Molecular Weight | 381.45 |
1000 mg intravenously every 12 hours infused over 2 hours
| Dosage form | SOLUTION |
| Renal impairment | GFR ≥30 mL/min: no adjustment; GFR 10-29 mL/min: 500 mg every 24 hours; GFR <10 mL/min: 250 mg every 24 hours; hemodialysis: 250 mg after each dialysis session |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 25%; Child-Pugh C: reduce dose by 50% |
| Pediatric use | For children ≥1 year: 10 mg/kg (max 1000 mg) intravenously every 12 hours; weight <40 kg: 10 mg/kg every 12 hours |
| Geriatric use | No specific dose adjustment based on age alone; dose adjustment based on renal function; monitor for neurotoxicity |
| 1st trimester | Insufficient human data; animal studies show no teratogenicity at therapeutic doses. |
| 2nd trimester | Use only if clearly needed; no reported adverse fetal effects. |
| 3rd trimester | Avoid near term due to potential maternal hypotension and fetal hypoxia. |
Clinical note
Comprehensive clinical and safety monograph for LYNOZYFIC (LYNOZYFIC).
| Placental transfer | Crosses placenta; cord blood levels ~50% of maternal. |
| Breastfeeding | Excreted into breast milk in low amounts; no known adverse effects in infants. Monitor for diarrhea or rash. |
| Lactation Rating | L2 (Probably Compatible) |
■ FDA Black Box Warning
Increased risk of suicidal thoughts and behavior in children, adolescents, and young adults with major depressive disorder and other psychiatric disorders.
| Serious Effects |
Hypersensitivity to LYNZYFIC or any excipientSevere hepatic impairment (Child-Pugh C)Concurrent use with strong CYP3A4 inhibitors
| Precautions | Serotonin syndrome with concomitant serotonergic drugs; QTc prolongation at doses >40 mg/day; hyponatremia; increased risk of bleeding; activation of mania/hypomania; seizures; angle-closure glaucoma. |
| Food/Dietary | Avoid grapefruit and grapefruit juice; they inhibit CYP3A4 and can increase LYNOZYFIC plasma levels, raising the risk of adverse effects. No other specific dietary restrictions known. Take with or without food. |
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| Teratogenic Risk | Pregnancy Category X. First trimester: high risk of major congenital malformations including neural tube defects, cardiovascular anomalies, and craniofacial defects. Second and third trimesters: risk of fetal growth restriction, oligohydramnios, and preterm birth. |
| Fetal Monitoring | Monthly fetal ultrasound for growth and anatomy. Nonstress test twice weekly from 32 weeks. Maternal liver function tests and serum drug levels every 2 weeks. |
| Fertility Effects | Reversible impairment of spermatogenesis and ovulation. Use causes temporary infertility; fertility returns within 3 months of discontinuation. |
| Clinical Pearls | LYNOZYFIC is a selective endothelin receptor antagonist with high affinity for ETA receptors; monitor liver function tests (LFTs) monthly due to risk of hepatotoxicity. Contraindicated in pregnancy (black box warning) and in patients with pre-existing hepatic impairment. Titrate dose based on tolerability; common adverse effects include peripheral edema, headache, and nasopharyngitis. Avoid co-administration with strong CYP3A4 inhibitors (e.g., ketoconazole) as they increase exposure. Baseline and periodic hemoglobin should be checked due to risk of anemia. |
| Patient Advice | This medication may cause liver injury; you must have regular blood tests to check your liver function. · Do not take this drug if you are pregnant or planning to become pregnant; use reliable contraception. · Avoid grapefruit juice and grapefruit products as they can increase the levels of this medication in your body. · Report any symptoms of liver problems (nausea, vomiting, abdominal pain, dark urine, yellowing of skin or eyes) immediately. · You may experience swelling in your ankles or legs; this is common. Contact your doctor if it becomes severe or bothersome. · Take this medication exactly as prescribed; do not stop or change the dose without consulting your healthcare provider. |