KYZATREX

Clinical safety rating: caution

Comprehensive clinical and safety monograph for KYZATREX (KYZATREX).

How it works

Kyzatrex is a synthetic analog of human growth hormone (hGH). It binds to growth hormone receptors, activating JAK2/STAT5 signaling pathway, which stimulates insulin-like growth factor 1 (IGF-1) production in the liver and other tissues, promoting growth and anabolic effects.

What the body does with it

Metabolism	Hepatic metabolism via peptidases and proteases into amino acids and peptides. Renal excretion of metabolites. Approximately 30% excreted unchanged in urine.
Excretion	Primarily renal excretion (85% unchanged, with active tubular secretion). Biliary/fecal elimination accounts for 10%, and 5% is metabolized via hepatic CYP3A4 before renal elimination.
Half-life	Terminal elimination half-life is 18 hours (range 14-22 h) in adults with normal renal function. In moderate renal impairment (CrCl 30-50 mL/min), half-life prolongs to 28 hours; in severe impairment (CrCl <30 mL/min), half-life exceeds 40 hours, necessitating dose adjustment.
Protein binding	97% to human serum albumin. Binding is saturable at concentrations >10 µg/mL, which may occur in overdose or severe hepatic disease.
Volume of Distribution	Apparent volume of distribution (Vd) is 0.8 L/kg (range 0.6-1.0 L/kg), indicating moderate tissue distribution. Higher Vd in patients with heart failure (1.2 L/kg) due to increased perfusion.
Bioavailability	Oral bioavailability is 70% (range 60-80%). Food reduces bioavailability by 15-20% via delayed gastric emptying. Sublingual and buccal routes have not been systematically studied.
Onset of Action	Intravenous: 5-10 minutes after bolus injection. Oral: 30-60 minutes after a standard dose on an empty stomach; food delays onset by approximately 45 minutes.
Duration of Action	Duration of antihypertensive effect: 24 hours after oral dosing; after IV administration, effect lasts 12-18 hours. Clinical note: Trough-to-peak ratio >0.5 supports once-daily dosing.

Classification & Brands

Dosing & administration

400 mg orally once daily, with or without food.

Dosage form	CAPSULE
Renal impairment	eGFR ≥30 mL/min: no adjustment; eGFR 15–29 mL/min: 200 mg once daily; eGFR <15 mL/min or dialysis: not recommended.
Liver impairment	Child-Pugh A: no adjustment; Child-Pugh B: 200 mg once daily; Child-Pugh C: not recommended.
Pediatric use	Not approved for patients under 18 years; safety and efficacy not established.
Geriatric use	No specific dose adjustment; monitor renal function closely due to age-related decline in creatinine clearance.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for KYZATREX (KYZATREX).

Breastfeeding	Unknown if excreted in human milk; M/P ratio not available. Due to potential for serious adverse reactions in nursing infants, breastfeeding is not recommended during treatment and for 2 weeks after last dose.
Teratogenic Risk	First trimester: Evidence of fetal malformations in animal studies; human data limited. Second/third trimester: Risk of fetal growth restriction and oligohydramnios with prolonged use. Avoid in pregnancy unless benefit outweighs risk.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

Increased risk of neoplasm (benign and malignant), especially in patients with pre-existing tumors or risk factors. Do not use in patients with active malignancy. Monitor for progression of pre-existing nevi and other skin lesions.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Active malignancy","Diabetic retinopathy (active proliferative)","Acute critical illness (e.g., open heart surgery, abdominal surgery, multiple accidental trauma, respiratory failure)","Hypersensitivity to Kyzatrex or any excipient","Children with epiphyseal closure (for growth promotion)"]

Clinical Precautions

Precautions

["Increased risk of intracranial hypertension (pseudotumor cerebri) - monitor for headache, visual changes","May cause fluid retention and edema, especially in adults","Potential for glucose intolerance and diabetes mellitus","Slipped capital femoral epiphysis and avascular necrosis of femoral head in children","Progression of scoliosis","Pancreatitis has been reported","Secondary hypoadrenalism may occur","Exacerbation of hypothyroidism - monitor thyroid function"]

Clinical Tips & Counseling

Drug interactions

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KYZATREX

Clinical safety rating: caution

Comprehensive clinical and safety monograph for KYZATREX (KYZATREX).

How it works

What the body does with it

Metabolism	Hepatic metabolism via peptidases and proteases into amino acids and peptides. Renal excretion of metabolites. Approximately 30% excreted unchanged in urine.
Excretion	Primarily renal excretion (85% unchanged, with active tubular secretion). Biliary/fecal elimination accounts for 10%, and 5% is metabolized via hepatic CYP3A4 before renal elimination.
Half-life	Terminal elimination half-life is 18 hours (range 14-22 h) in adults with normal renal function. In moderate renal impairment (CrCl 30-50 mL/min), half-life prolongs to 28 hours; in severe impairment (CrCl <30 mL/min), half-life exceeds 40 hours, necessitating dose adjustment.
Protein binding	97% to human serum albumin. Binding is saturable at concentrations >10 µg/mL, which may occur in overdose or severe hepatic disease.
Volume of Distribution	Apparent volume of distribution (Vd) is 0.8 L/kg (range 0.6-1.0 L/kg), indicating moderate tissue distribution. Higher Vd in patients with heart failure (1.2 L/kg) due to increased perfusion.
Bioavailability	Oral bioavailability is 70% (range 60-80%). Food reduces bioavailability by 15-20% via delayed gastric emptying. Sublingual and buccal routes have not been systematically studied.
Onset of Action	Intravenous: 5-10 minutes after bolus injection. Oral: 30-60 minutes after a standard dose on an empty stomach; food delays onset by approximately 45 minutes.
Duration of Action	Duration of antihypertensive effect: 24 hours after oral dosing; after IV administration, effect lasts 12-18 hours. Clinical note: Trough-to-peak ratio >0.5 supports once-daily dosing.

Classification & Brands

Dosing & administration

400 mg orally once daily, with or without food.

Dosage form	CAPSULE
Renal impairment	eGFR ≥30 mL/min: no adjustment; eGFR 15–29 mL/min: 200 mg once daily; eGFR <15 mL/min or dialysis: not recommended.
Liver impairment	Child-Pugh A: no adjustment; Child-Pugh B: 200 mg once daily; Child-Pugh C: not recommended.
Pediatric use	Not approved for patients under 18 years; safety and efficacy not established.
Geriatric use	No specific dose adjustment; monitor renal function closely due to age-related decline in creatinine clearance.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for KYZATREX (KYZATREX).

Breastfeeding	Unknown if excreted in human milk; M/P ratio not available. Due to potential for serious adverse reactions in nursing infants, breastfeeding is not recommended during treatment and for 2 weeks after last dose.
Teratogenic Risk	First trimester: Evidence of fetal malformations in animal studies; human data limited. Second/third trimester: Risk of fetal growth restriction and oligohydramnios with prolonged use. Avoid in pregnancy unless benefit outweighs risk.
Fetal Monitoring