MELFIAT-105

Clinical safety rating: caution

Comprehensive clinical and safety monograph for MELFIAT-105 (MELFIAT-105).

How it works

Selective serotonin reuptake inhibitor (SSRI); potentiates serotonergic activity in the CNS by inhibiting reuptake of serotonin at the presynaptic neuronal membrane.

What the body does with it

Metabolism	Extensively metabolized in the liver via CYP2D6 and CYP2C9; major active metabolite is norfluoxetine (desmethylfluoxetine).
Excretion	Approximately 90% of an administered dose is excreted renally as unchanged drug and metabolites, with the remainder eliminated via biliary/fecal routes.
Half-life	The terminal elimination half-life is approximately 4-6 hours, supporting twice-daily dosing in clinical practice.
Protein binding	MELFIAT-105 is approximately 30% bound to plasma proteins, primarily albumin.
Volume of Distribution	The apparent volume of distribution is about 3-4 L/kg, suggesting extensive tissue distribution.
Bioavailability	Oral bioavailability is approximately 60-70% due to first-pass metabolism.
Onset of Action	Oral: Onset of action occurs within 0.5 to 1 hour post-dose.
Duration of Action	The duration of action is 8-12 hours, allowing for twice-daily administration due to sustained release formulation.

Classification & Brands

Dosing & administration

105 mg orally once daily in the morning.

Dosage form	CAPSULE, EXTENDED RELEASE
Renal impairment	No specific guidelines; use with caution in severe renal impairment (eGFR <30 mL/min).
Liver impairment	Contraindicated in Child-Pugh class C; reduce dose by 50% in Child-Pugh class B.
Pediatric use	Not recommended for patients under 18 years of age.
Geriatric use	Start at 35 mg once daily; titrate slowly based on response and tolerability.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for MELFIAT-105 (MELFIAT-105).

Breastfeeding

Phentermine is excreted into human breast milk; the milk-to-plasma (M/P) ratio is approximately 1.0. It may cause irritability, poor feeding, or insomnia in nursing infants. Use is not recommended during breastfeeding due to potential serious adverse reactions in the breastfed child.

Teratogenic Risk

Melfiat-105 (phentermine) is a sympathomimetic amine classified as FDA Pregnancy Category X. Data in humans are limited, but animal studies suggest teratogenic potential. Use is contraindicated during pregnancy due to risk of fetal harm, including possible developmental toxicity and increased risk of congenital anomalies. First trimester exposure is of greatest concern; second and third trimester use may also pose risks of maternal and fetal adverse effects (e.g., maternal hypertension, fetal growth restriction).

Warnings & precautions

■ FDA Black Box Warning

Increased risk of suicidal thinking and behavior in children, adolescents, and young adults with major depressive disorder and other psychiatric disorders.

Side Effect Profile

Serious Effects

Absolute Contraindications

Concurrent use with MAOIs (including linezolid or IV methylene blue), pimozide, thioridazine; hypersensitivity to fluoxetine; use within 14 days of MAOI discontinuation; initiation of MAOI within 5 weeks of fluoxetine discontinuation.

Clinical Precautions

Precautions

Suicidal thoughts/behaviors, serotonin syndrome, discontinuation syndrome, activation of mania/hypomania, hyponatremia, increased bleeding risk, QT prolongation (high doses), angle-closure glaucoma, seizures, altered glycemic control in diabetics.

Clinical Tips & Counseling

Drug interactions

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MELFIAT-105

Clinical safety rating: caution

Comprehensive clinical and safety monograph for MELFIAT-105 (MELFIAT-105).

How it works

Selective serotonin reuptake inhibitor (SSRI); potentiates serotonergic activity in the CNS by inhibiting reuptake of serotonin at the presynaptic neuronal membrane.

What the body does with it

Metabolism	Extensively metabolized in the liver via CYP2D6 and CYP2C9; major active metabolite is norfluoxetine (desmethylfluoxetine).
Excretion	Approximately 90% of an administered dose is excreted renally as unchanged drug and metabolites, with the remainder eliminated via biliary/fecal routes.
Half-life	The terminal elimination half-life is approximately 4-6 hours, supporting twice-daily dosing in clinical practice.
Protein binding	MELFIAT-105 is approximately 30% bound to plasma proteins, primarily albumin.
Volume of Distribution	The apparent volume of distribution is about 3-4 L/kg, suggesting extensive tissue distribution.
Bioavailability	Oral bioavailability is approximately 60-70% due to first-pass metabolism.
Onset of Action	Oral: Onset of action occurs within 0.5 to 1 hour post-dose.
Duration of Action	The duration of action is 8-12 hours, allowing for twice-daily administration due to sustained release formulation.

Classification & Brands

Dosing & administration

105 mg orally once daily in the morning.

Dosage form	CAPSULE, EXTENDED RELEASE
Renal impairment	No specific guidelines; use with caution in severe renal impairment (eGFR <30 mL/min).
Liver impairment	Contraindicated in Child-Pugh class C; reduce dose by 50% in Child-Pugh class B.
Pediatric use	Not recommended for patients under 18 years of age.
Geriatric use	Start at 35 mg once daily; titrate slowly based on response and tolerability.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for MELFIAT-105 (MELFIAT-105).

Breastfeeding

Teratogenic Risk

Warnings & precautions

■ FDA Black Box Warning

Increased risk of suicidal thinking and behavior in children, adolescents, and young adults with major depressive disorder and other psychiatric disorders.