TENATHAN

Clinical safety rating: caution

Comprehensive clinical and safety monograph for TENATHAN (TENATHAN).

How it works

TENATHAN is a selective serotonin reuptake inhibitor (SSRI) that potentiates serotonergic activity in the central nervous system by inhibiting the reuptake of serotonin at the presynaptic neuronal membrane, leading to increased serotonin levels in the synaptic cleft.

What the body does with it

Metabolism	TENATHAN is extensively metabolized in the liver, primarily via cytochrome P450 enzymes CYP2D6 and CYP3A4. The major metabolite is N-desmethyltenathan, which has minimal pharmacological activity. Renal excretion of metabolites and unchanged drug accounts for elimination.
Excretion	Primarily renal excretion as unchanged drug (60-70%) and metabolites (20-30%); biliary/fecal elimination accounts for <10%.
Half-life	Terminal elimination half-life is 4-6 hours; in severe renal impairment (CrCl <30 mL/min) may extend to 8-12 hours, requiring dose adjustment.
Protein binding	90-95% bound primarily to albumin and alpha-1-acid glycoprotein.
Volume of Distribution	Vd 1.5-2.0 L/kg, indicating extensive tissue distribution. Higher in obesity (up to 2.5 L/kg) due to lipophilicity.
Bioavailability	Oral: 40-60% (first-pass effect); Intramuscular: 75-85%; Intravenous: 100%.
Onset of Action	Oral: 30-45 minutes; Intravenous: 2-5 minutes; Intramuscular: 10-20 minutes.
Duration of Action	Oral: 4-6 hours; Intravenous: 2-4 hours; duration prolonged in hepatic impairment. Not recommended for long-term use due to tolerance development.

Classification & Brands

Dosing & administration

1 tablet (40 mg) orally once daily, increased to 80 mg once daily if needed after 4 weeks.

Dosage form	TABLET
Renal impairment	GFR ≥30 mL/min: no adjustment; GFR <30 mL/min: contraindicated.
Liver impairment	Child-Pugh A: no adjustment; Child-Pugh B: reduce dose to 20 mg once daily; Child-Pugh C: contraindicated.
Pediatric use	Not approved in pediatric patients; no established dosing.
Geriatric use	Initiate at 20 mg once daily due to increased sensitivity; titrate cautiously.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for TENATHAN (TENATHAN).

Breastfeeding	It is unknown whether TENATHAN is excreted in human milk. M/P ratio is unknown. Due to the potential for serious adverse reactions in nursing infants, breastfeeding should be discontinued during treatment.
Teratogenic Risk	There is no data on TENATHAN in pregnancy. Animal studies have not been conducted. The fetal risk is unknown; therefore, use during pregnancy only if the potential benefit justifies the potential risk.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

WARNING: SUICIDAL THOUGHTS AND BEHAVIORS. Antidepressants increased the risk of suicidal thoughts and behaviors in pediatric and young adult patients in short-term studies. Closely monitor for clinical worsening, suicidality, or unusual changes in behavior. Advise families and caregivers about the need for close observation and communication with the prescriber.

Side Effect Profile

Serious Effects

Absolute Contraindications

1. Hypersensitivity to TENATHAN or any excipients. 2. Concurrent use of MAOIs or within 14 days of MAOI discontinuation. 3. Concurrent use of pimozide or thioridazine due to risk of QT prolongation. 4. History of serotonin syndrome with SSRI/SNRI use. 5. Unstable seizure disorders. 6. Severe renal impairment (CrCl < 15 mL/min) without dose adjustment protocol.

Clinical Precautions

Precautions

1. Serotonin syndrome: potentially life-threatening condition with co-administration of other serotonergic agents. 2. Discontinuation syndrome: gradual dose reduction recommended. 3. QT prolongation: caution in patients with risk factors for QT prolongation. 4. Hyponatremia: monitor in elderly and volume-depleted patients. 5. Bone fracture risk: increased risk in older adults. 6. Seizures: use with caution in patients with seizure disorders.

Clinical Tips & Counseling

Drug interactions

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TENATHAN

Clinical safety rating: caution

Comprehensive clinical and safety monograph for TENATHAN (TENATHAN).

How it works

What the body does with it

Metabolism	TENATHAN is extensively metabolized in the liver, primarily via cytochrome P450 enzymes CYP2D6 and CYP3A4. The major metabolite is N-desmethyltenathan, which has minimal pharmacological activity. Renal excretion of metabolites and unchanged drug accounts for elimination.
Excretion	Primarily renal excretion as unchanged drug (60-70%) and metabolites (20-30%); biliary/fecal elimination accounts for <10%.
Half-life	Terminal elimination half-life is 4-6 hours; in severe renal impairment (CrCl <30 mL/min) may extend to 8-12 hours, requiring dose adjustment.
Protein binding	90-95% bound primarily to albumin and alpha-1-acid glycoprotein.
Volume of Distribution	Vd 1.5-2.0 L/kg, indicating extensive tissue distribution. Higher in obesity (up to 2.5 L/kg) due to lipophilicity.
Bioavailability	Oral: 40-60% (first-pass effect); Intramuscular: 75-85%; Intravenous: 100%.
Onset of Action	Oral: 30-45 minutes; Intravenous: 2-5 minutes; Intramuscular: 10-20 minutes.
Duration of Action	Oral: 4-6 hours; Intravenous: 2-4 hours; duration prolonged in hepatic impairment. Not recommended for long-term use due to tolerance development.

Classification & Brands

Dosing & administration

1 tablet (40 mg) orally once daily, increased to 80 mg once daily if needed after 4 weeks.

Dosage form	TABLET
Renal impairment	GFR ≥30 mL/min: no adjustment; GFR <30 mL/min: contraindicated.
Liver impairment	Child-Pugh A: no adjustment; Child-Pugh B: reduce dose to 20 mg once daily; Child-Pugh C: contraindicated.
Pediatric use	Not approved in pediatric patients; no established dosing.
Geriatric use	Initiate at 20 mg once daily due to increased sensitivity; titrate cautiously.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for TENATHAN (TENATHAN).

Breastfeeding	It is unknown whether TENATHAN is excreted in human milk. M/P ratio is unknown. Due to the potential for serious adverse reactions in nursing infants, breastfeeding should be discontinued during treatment.
Teratogenic Risk	There is no data on TENATHAN in pregnancy. Animal studies have not been conducted. The fetal risk is unknown; therefore, use during pregnancy only if the potential benefit justifies the potential risk.
Fetal Monitoring