RYKINDO

Clinical safety rating: caution

Comprehensive clinical and safety monograph for RYKINDO (RYKINDO).

How it works

RYKINDO (pitolisant) is a selective histamine H3 receptor antagonist/inverse agonist. It enhances the activity of brain histaminergic neurons by blocking H3 autoreceptors, thereby increasing histamine release. This promotes wakefulness and reduces excessive daytime sleepiness.

What the body does with it

Metabolism	Primarily metabolized by CYP3A4, with minor contributions from CYP2D6 and CYP1A2. Undergoes glucuronidation and oxidation. Major metabolite is inactive.
Excretion	RYKINDO (risperidone long-acting injectable) is primarily excreted via urine (70%) as active moiety (risperidone and 9-hydroxyrisperidone), with approximately 14% excreted in feces. Renal clearance accounts for ~60% of total clearance.
Half-life	Terminal elimination half-life of risperidone is approximately 3-6 hours, and for 9-hydroxyrisperidone (paliperidone) 21-30 hours in extensive metabolizers. With the long-acting formulation, effective half-life for the release profile is 3-6 days due to slow absorption from gluteal muscle.
Protein binding	Risperidone is 90% bound to plasma proteins (albumin and alpha-1-acid glycoprotein); 9-hydroxyrisperidone is 77% bound.
Volume of Distribution	Volume of distribution at steady state is approximately 1-2 L/kg, indicating extensive tissue distribution, with a central volume of 0.5-1.5 L/kg.
Bioavailability	Intramuscular injection (long-acting): relative bioavailability is approximately 100% compared to oral solution after 4 weeks. Oral immediate release: absolute bioavailability is 66-70% (first-pass metabolism).
Onset of Action	Intramuscular injection: therapeutic effect typically observed within 3-4 weeks (requires oral supplementation for first 3 weeks). Oral immediate release: onset of antipsychotic effect occurs within 1-2 hours post-dose.
Duration of Action	Intramuscular depot: duration of action is 2 weeks for the recommended dosing interval (every 2 weeks). Clinical effect is maintained over the dosing interval. Oral: duration of effect is 12-24 hours necessitating daily dosing.

Classification & Brands

Dosing & administration

10 mg orally once daily, increased to 20 mg orally once daily after 1 week if tolerated, with a maximum of 20 mg/day.

Dosage form	FOR SUSPENSION, EXTENDED RELEASE
Renal impairment	No dose adjustment required for mild to moderate renal impairment (eGFR ≥30 mL/min). For severe renal impairment (eGFR <30 mL/min), reduce starting dose to 5 mg once daily, with a maximum of 10 mg/day.
Liver impairment	For Child-Pugh class A or B: no adjustment needed. For Child-Pugh class C: contraindicated.
Pediatric use	Not approved for use in pediatric patients below 18 years of age.
Geriatric use	No specific dose adjustment recommended, but elderly patients may be more sensitive to adverse effects; initiate at 5 mg once daily and 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 RYKINDO (RYKINDO).

Breastfeeding	Risperidone and its active metabolite 9-hydroxyrisperidone are excreted in breast milk; relative infant dose estimated at approximately 4-17% of maternal weight-adjusted dose. M/P ratio not established. Monitor infant for sedation, irritability, and poor feeding. Breastfeeding not recommended unless clearly necessary.
Teratogenic Risk	RYKINDO (risperidone) is classified as Pregnancy Category C. First trimester: limited human data; animal studies show increased fetal deaths and cleft palate at high doses. Second and third trimesters: risk of extrapyramidal symptoms and withdrawal in neonates after third trimester exposure. Use only if benefit outweighs risk.

Warnings & precautions

■ FDA Black Box Warning

No FDA boxed warning.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Severe hepatic impairment (Child-Pugh C)","Concurrent use with monoamine oxidase inhibitors (MAOIs)","Known hypersensitivity to pitolisant or any excipients"]

Clinical Precautions

Precautions

["Prolongation of QT interval: Avoid use in patients with known QT prolongation or concurrent use of QT-prolonging drugs","Hepatic impairment: Contraindicated in severe hepatic impairment; dose adjustment required in moderate impairment","Renal impairment: Not recommended in severe renal impairment (CrCl < 30 mL/min)","Psychiatric effects: May cause anxiety, insomnia, or irritability; monitor for psychiatric symptoms","Driving impairment: Caution when driving until individual response is established"]

Clinical Tips & Counseling

Drug interactions

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RYKINDO

Clinical safety rating: caution

Comprehensive clinical and safety monograph for RYKINDO (RYKINDO).

How it works

What the body does with it

Metabolism	Primarily metabolized by CYP3A4, with minor contributions from CYP2D6 and CYP1A2. Undergoes glucuronidation and oxidation. Major metabolite is inactive.
Excretion	RYKINDO (risperidone long-acting injectable) is primarily excreted via urine (70%) as active moiety (risperidone and 9-hydroxyrisperidone), with approximately 14% excreted in feces. Renal clearance accounts for ~60% of total clearance.
Half-life	Terminal elimination half-life of risperidone is approximately 3-6 hours, and for 9-hydroxyrisperidone (paliperidone) 21-30 hours in extensive metabolizers. With the long-acting formulation, effective half-life for the release profile is 3-6 days due to slow absorption from gluteal muscle.
Protein binding	Risperidone is 90% bound to plasma proteins (albumin and alpha-1-acid glycoprotein); 9-hydroxyrisperidone is 77% bound.
Volume of Distribution	Volume of distribution at steady state is approximately 1-2 L/kg, indicating extensive tissue distribution, with a central volume of 0.5-1.5 L/kg.
Bioavailability	Intramuscular injection (long-acting): relative bioavailability is approximately 100% compared to oral solution after 4 weeks. Oral immediate release: absolute bioavailability is 66-70% (first-pass metabolism).
Onset of Action	Intramuscular injection: therapeutic effect typically observed within 3-4 weeks (requires oral supplementation for first 3 weeks). Oral immediate release: onset of antipsychotic effect occurs within 1-2 hours post-dose.
Duration of Action	Intramuscular depot: duration of action is 2 weeks for the recommended dosing interval (every 2 weeks). Clinical effect is maintained over the dosing interval. Oral: duration of effect is 12-24 hours necessitating daily dosing.

Classification & Brands

Dosing & administration

10 mg orally once daily, increased to 20 mg orally once daily after 1 week if tolerated, with a maximum of 20 mg/day.

Dosage form	FOR SUSPENSION, EXTENDED RELEASE
Renal impairment	No dose adjustment required for mild to moderate renal impairment (eGFR ≥30 mL/min). For severe renal impairment (eGFR <30 mL/min), reduce starting dose to 5 mg once daily, with a maximum of 10 mg/day.
Liver impairment	For Child-Pugh class A or B: no adjustment needed. For Child-Pugh class C: contraindicated.
Pediatric use	Not approved for use in pediatric patients below 18 years of age.
Geriatric use	No specific dose adjustment recommended, but elderly patients may be more sensitive to adverse effects; initiate at 5 mg once daily and 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 RYKINDO (RYKINDO).

Breastfeeding	Risperidone and its active metabolite 9-hydroxyrisperidone are excreted in breast milk; relative infant dose estimated at approximately 4-17% of maternal weight-adjusted dose. M/P ratio not established. Monitor infant for sedation, irritability, and poor feeding. Breastfeeding not recommended unless clearly necessary.
Teratogenic Risk	RYKINDO (risperidone) is classified as Pregnancy Category C. First trimester: limited human data; animal studies show increased fetal deaths and cleft palate at high doses. Second and third trimesters: risk of extrapyramidal symptoms and withdrawal in neonates after third trimester exposure. Use only if benefit outweighs risk.

Warnings & precautions

■ FDA Black Box Warning

No FDA boxed warning.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Severe hepatic impairment (Child-Pugh C)","Concurrent use with monoamine oxidase inhibitors (MAOIs)","Known hypersensitivity to pitolisant or any excipients"]