DESVENLAFAXINE
Clinical safety rating: caution
MAOIs can cause serotonin syndrome Can increase blood pressure and cause withdrawal symptoms upon discontinuation.
Selective serotonin and norepinephrine reuptake inhibitor (SNRI) that potentiates the activity of serotonin and norepinephrine in the central nervous system by blocking their reuptake at presynaptic neurons.
| Metabolism | Primarily metabolized by conjugation (UGT) and to a lesser extent by CYP3A4 to N,O-didesvenlafaxine; minimal CYP2D6 involvement. |
| Excretion | Renal: approximately 45% as unchanged desvenlafaxine and 23% as glucuronide conjugate. Fecal: minimal (<1%). Biliary: negligible. |
| Half-life | Terminal elimination half-life is approximately 11 hours (range 8.5-13 hours). This supports once-daily dosing without need for extended-release formulation. |
| Protein binding | Low protein binding: 30% bound to plasma proteins (primarily albumin and alpha-1-acid glycoprotein). |
| Volume of Distribution | Apparent volume of distribution (Vd/F) is approximately 3.4 L/kg, indicating extensive extravascular distribution. |
| Bioavailability | Oral: Absolute bioavailability is about 80%. |
| Onset of Action | Oral: Clinical improvement in depression and anxiety may be observed within 1-2 weeks, but full therapeutic effect may require 4-8 weeks. |
| Duration of Action | Oral: Duration of action is approximately 24 hours due to once-daily dosing. Steady-state achieved within 4-5 days. Clinical effects persist for several weeks after discontinuation. |
| Molecular Weight | 263.34 |
50 mg orally once daily, with or without food. May increase to 100 mg/day if tolerated and needed. Maximum dose 100 mg/day.
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | GFR 30-49 mL/min: 50 mg every 48 hours. GFR 15-29 mL/min: 50 mg every 72 hours. ESRD or on dialysis: 50 mg every 72 hours; not removed by dialysis. |
| Liver impairment | Child-Pugh Class A or B: no adjustment. Child-Pugh Class C: maximum dose 50 mg every 48 hours. |
| Pediatric use | Not approved for use in pediatric patients. Safety and effectiveness not established. |
| Geriatric use | No specific dose adjustment; consider starting at 25 mg daily due to potential for reduced renal function and increased sensitivity. Maximum dose 100 mg daily. |
| 1st trimester | Limited human data; animal studies show increased risk of fetal skeletal abnormalities and decreased survival at doses >10 times the maximum human dose. Potential risk of serotonin discontinuation syndrome in neonates exposed late in third trimester. |
| 2nd trimester | Limited human data; potential risk of serotonin discontinuation syndrome in neonates. Consider maternal benefit vs fetal risk. |
| 3rd trimester | Use in third trimester may increase risk of persistent pulmonary hypertension of the newborn (PPHN) and serotonin discontinuation syndrome in neonate (irritability, feeding difficulties, respiratory distress). |
Clinical note
MAOIs can cause serotonin syndrome Can increase blood pressure and cause withdrawal symptoms upon discontinuation.
| FDA category | Animal |
| Placental transfer | Desvenlafaxine crosses the placenta. Animal studies demonstrate placental transfer. Human data limited but likely similar to venlafaxine, which has a high placental transfer rate (maternal to fetal ratio ~1.0). |
■ FDA Black Box Warning
Antidepressants increased the risk of suicidal thinking and behavior in children, adolescents, and young adults in short-term studies. Monitor closely for clinical worsening, suicidality, or unusual changes in behavior.
| Common Effects | anxiety disorders |
| Serious Effects |
Concomitant use of monoamine oxidase inhibitors (MAOIs) or within 14 days of discontinuing an MAOIHypersensitivity to desvenlafaxine or any component of the formulationConcurrent use with linezolid or intravenous methylene blue (due to risk of serotonin syndrome)
| Precautions | Serotonin syndrome: Risk with co-administration of serotonergic drugs., Elevation of blood pressure: Dose-dependent; monitor blood pressure regularly., Activation of mania/hypomania: Screen for bipolar disorder., Angle-closure glaucoma: May cause mydriasis; risk in patients with narrow angles., Sexual dysfunction: May cause ejaculatory delay and impotence., Discontinuation syndrome: Taper dose gradually to avoid withdrawal symptoms., Hyponatremia: Risk particularly in elderly or volume-depleted patients. |
Loading safety data…
| Breastfeeding | Desvenlafaxine is excreted in human milk. In one study, the mean relative infant dose was 6.5% of weight-adjusted maternal dose. No adverse effects reported in breastfed infants, but long-term effects unknown. Monitor infant for serotonin-related symptoms. |
| Lactation Rating | L2 |
| Teratogenic Risk | Desvenlafaxine is classified as FDA Pregnancy Category C. Limited human data; animal studies have shown fetal harm at doses exceeding maximum recommended human dose. First trimester: No clear evidence of major malformations, but increased risk of spontaneous abortion reported. Second trimester: no specific risk identified. Third trimester: neonatal adaptation syndrome including respiratory distress, feeding difficulties, jitteriness, cyanosis, and apnea. Use only if potential benefit justifies risk. |
| Fetal Monitoring | Monitor for signs of neonatal adaptation syndrome at delivery. In pregnancy, monitor maternal blood pressure and heart rate regularly due to desvenlafaxine's potential to increase blood pressure. Assess for serotonin syndrome, especially when co-administered with other serotonergic drugs. Consider fetal ultrasound for growth and well-being if used long-term. |
| Fertility Effects | In animal studies, desvenlafaxine caused reduced fertility and impaired spermatogenesis at high doses. Human data are lacking; no clinical studies on fertility effects in women. Potential for reversible sexual dysfunction in men and women, which may indirectly affect fertility. Use with caution in patients attempting conception. |
| Food/Dietary | Desvenlafaxine has no known significant food interactions. However, taking with food may reduce nausea. Avoid alcohol as it exacerbates CNS depression. |
| Clinical Pearls | Desvenlafaxine is the active metabolite of venlafaxine and exhibits similar SNRI activity. It has linear pharmacokinetics and minimal CYP450 metabolism, reducing drug-drug interactions. Monitor blood pressure, especially at doses above 50 mg/day. Discontinuation syndrome is common; taper gradually. Onset of therapeutic effect may take 2–4 weeks. |
| Patient Advice | Take desvenlafaxine at the same time each day, preferably with or without food. · Do not stop abruptly; dosage must be tapered under medical supervision to avoid withdrawal symptoms. · Report any signs of suicidal thoughts, worsening depression, or unusual behavior changes. · Avoid driving or operating heavy machinery until you know how the medication affects you. · Inform your doctor if you have high blood pressure, glaucoma, or seizure disorder. · Avoid alcohol consumption as it may increase dizziness and drowsiness. |