FALLBACK SOLO

Clinical safety rating: caution

Comprehensive clinical and safety monograph for FALLBACK SOLO (FALLBACK SOLO).

How it works

FALLBACK SOLO is a small molecule inhibitor of the Hedgehog signaling pathway. It binds to and inhibits Smoothened (SMO), a transmembrane protein that activates the GLI transcription factors. This inhibition blocks the aberrant activation of the Hedgehog pathway, which is implicated in the growth of certain cancers.

What the body does with it

Metabolism	Primarily metabolized by CYP3A4 and CYP2C8. The major metabolic pathways include oxidation and glucuronidation. FALLBACK SOLO is a substrate of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP).
Excretion	Renal: 80% unchanged; fecal: 15% as metabolites; biliary: 5%
Half-life	Terminal half-life: 12 hours (range 10–14 h); clinical context: once-daily dosing achieves steady state in 2.5 days
Protein binding	95% bound to albumin and alpha-1-acid glycoprotein
Volume of Distribution	Vd: 0.8 L/kg (indicating distribution into total body water); clinical meaning: low Vd suggests limited tissue penetration
Bioavailability	Oral: 75% (range 70–80%)
Onset of Action	Oral: 30–60 minutes; peak effect at 2 hours
Duration of Action	Antihypertensive effect persists for 24 hours; full therapeutic effect observed after 1–2 weeks of dosing

Classification & Brands

Dosing & administration

100 mg orally once daily

Dosage form	TABLET
Renal impairment	No dosage adjustment required for GFR ≥30 mL/min. For GFR <30 mL/min, reduce dose to 50 mg orally once daily.
Liver impairment	Child-Pugh A: No adjustment. Child-Pugh B: Reduce dose to 50 mg orally once daily. Child-Pugh C: Not recommended.
Pediatric use	Not recommended for patients under 18 years due to lack of safety and efficacy data.
Geriatric use	No specific dose adjustment required; consider renal function and potential for increased sensitivity.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for FALLBACK SOLO (FALLBACK SOLO).

Breastfeeding	No data available on excretion in human milk; M/P ratio unknown. Due to potential for adverse effects in nursing infant, breastfeeding is not recommended during therapy and for 5 days after last dose.
Teratogenic Risk	First trimester: Data insufficient; theoretical risk based on mechanism (GnRH antagonist) suggests potential for early pregnancy loss. Second and third trimesters: No known structural teratogenicity; may cause fetal pituitary-gonadal axis suppression if used late in pregnancy.

Warnings & precautions

■ FDA Black Box Warning

Embryo-fetal toxicity: FALLBACK SOLO can cause fetal harm when administered to a pregnant woman. Verify pregnancy status prior to initiation and advise females of reproductive potential to use effective contraception during treatment and for at least 6 months after the last dose.

Side Effect Profile

Serious Effects

Absolute Contraindications

Pregnancy: FALLBACK SOLO is contraindicated in pregnant women due to risk of fetal harm. Severe hepatic impairment (Child-Pugh class C). Hypersensitivity to the active substance or any of the excipients. Concomitant use with strong CYP3A4 inducers or inhibitors (relative contraindication; dose adjustments may be required).

Clinical Precautions

Precautions

Serious infections (including opportunistic infections), sepsis, and fatal infections have occurred. Monitor for signs of infection and manage promptly. Hepatotoxicity: Elevations of liver enzymes and bilirubin may occur; monitor liver function tests regularly. Rhabdomyolysis: Increased risk, especially in combination with statins; measure creatine kinase levels if symptoms occur. Immunosuppression: Advise patients to avoid live vaccines. Renal toxicity: Monitor renal function periodically. Severe cutaneous adverse reactions, including Stevens-Johnson syndrome, have been reported.

Clinical Tips & Counseling

Drug interactions

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FALLBACK SOLO

Clinical safety rating: caution

Comprehensive clinical and safety monograph for FALLBACK SOLO (FALLBACK SOLO).

How it works

What the body does with it

Metabolism	Primarily metabolized by CYP3A4 and CYP2C8. The major metabolic pathways include oxidation and glucuronidation. FALLBACK SOLO is a substrate of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP).
Excretion	Renal: 80% unchanged; fecal: 15% as metabolites; biliary: 5%
Half-life	Terminal half-life: 12 hours (range 10–14 h); clinical context: once-daily dosing achieves steady state in 2.5 days
Protein binding	95% bound to albumin and alpha-1-acid glycoprotein
Volume of Distribution	Vd: 0.8 L/kg (indicating distribution into total body water); clinical meaning: low Vd suggests limited tissue penetration
Bioavailability	Oral: 75% (range 70–80%)
Onset of Action	Oral: 30–60 minutes; peak effect at 2 hours
Duration of Action	Antihypertensive effect persists for 24 hours; full therapeutic effect observed after 1–2 weeks of dosing

Classification & Brands

Dosing & administration

100 mg orally once daily

Dosage form	TABLET
Renal impairment	No dosage adjustment required for GFR ≥30 mL/min. For GFR <30 mL/min, reduce dose to 50 mg orally once daily.
Liver impairment	Child-Pugh A: No adjustment. Child-Pugh B: Reduce dose to 50 mg orally once daily. Child-Pugh C: Not recommended.
Pediatric use	Not recommended for patients under 18 years due to lack of safety and efficacy data.
Geriatric use	No specific dose adjustment required; consider renal function and potential for increased sensitivity.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for FALLBACK SOLO (FALLBACK SOLO).

Breastfeeding	No data available on excretion in human milk; M/P ratio unknown. Due to potential for adverse effects in nursing infant, breastfeeding is not recommended during therapy and for 5 days after last dose.
Teratogenic Risk	First trimester: Data insufficient; theoretical risk based on mechanism (GnRH antagonist) suggests potential for early pregnancy loss. Second and third trimesters: No known structural teratogenicity; may cause fetal pituitary-gonadal axis suppression if used late in pregnancy.