ANOQUAN

Clinical safety rating: caution

Comprehensive clinical and safety monograph for ANOQUAN (ANOQUAN).

How it works

Guanabenz is a centrally acting alpha-2 adrenergic agonist that reduces sympathetic outflow from the brain, leading to decreased peripheral vascular resistance and lowered blood pressure.

What the body does with it

Metabolism	Hepatic metabolism via oxidation and conjugation; metabolites excreted renally.
Excretion	Renal excretion accounts for approximately 70% of the dose (50% as unchanged drug, 20% as inactive metabolites); biliary/fecal excretion accounts for 30%.
Half-life	Terminal elimination half-life is 12-15 hours in adults with normal renal function; prolonged to 24-48 hours in severe renal impairment (CrCl <30 mL/min).
Protein binding	Approximately 90% bound to albumin.
Volume of Distribution	0.8-1.2 L/kg, indicating extensive distribution into total body water.
Bioavailability	Oral: 60-70% due to first-pass metabolism.
Onset of Action	Oral: 1-2 hours; intravenous: within 5-10 minutes.
Duration of Action	Oral: 8-12 hours; intravenous: 6-8 hours. Duration may be extended in hepatic impairment.

Classification & Brands

Dosing & administration

100 mg orally twice daily

Dosage form	CAPSULE
Renal impairment	GFR 30-50 mL/min: 100 mg once daily; GFR <30 mL/min: 50 mg once daily; not recommended for GFR <15 mL/min
Liver impairment	Child-Pugh A: no adjustment; Child-Pugh B: 50 mg twice daily; Child-Pugh C: not recommended
Pediatric use	Not approved for pediatric use; no established dosing
Geriatric use	No specific adjustment; monitor renal function and consider reduced initial dose (50 mg twice daily) in patients >65 years with renal impairment

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for ANOQUAN (ANOQUAN).

Breastfeeding	Excreted in human milk. M/P ratio not determined. Avoid breastfeeding due to potential for serious adverse reactions in the nursing infant, including renal impairment and electrolyte disturbances.
Teratogenic Risk	Pregnancy Category X. Anoquan is contraindicated in all trimesters. In the first trimester, there is a high risk of major cardiac malformations and neural tube defects. Second and third trimester exposure is associated with fetal nephrotoxicity, oligohydramnios, and premature closure of the ductus arteriosus.

Warnings & precautions

■ FDA Black Box Warning

No FDA black box warning.

Side Effect Profile

Common Effects	Burning sensation Tingling Rash
Serious Effects

Absolute Contraindications

Known hypersensitivity to guanabenz; patients with severe hepatic or renal impairment.

Clinical Precautions

Precautions	Rebound hypertension upon abrupt discontinuation; sedation and drowsiness; potential for orthostatic hypotension; caution in patients with severe coronary insufficiency or cerebrovascular disease.
Food/Dietary	Avoid grapefruit and grapefruit juice as they may increase quinine levels. Take with a full glass of water. May be taken with meals to reduce nausea.

Clinical Tips & Counseling

Drug interactions

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ANOQUAN

Clinical safety rating: caution

Comprehensive clinical and safety monograph for ANOQUAN (ANOQUAN).

How it works

Guanabenz is a centrally acting alpha-2 adrenergic agonist that reduces sympathetic outflow from the brain, leading to decreased peripheral vascular resistance and lowered blood pressure.

What the body does with it

Metabolism	Hepatic metabolism via oxidation and conjugation; metabolites excreted renally.
Excretion	Renal excretion accounts for approximately 70% of the dose (50% as unchanged drug, 20% as inactive metabolites); biliary/fecal excretion accounts for 30%.
Half-life	Terminal elimination half-life is 12-15 hours in adults with normal renal function; prolonged to 24-48 hours in severe renal impairment (CrCl <30 mL/min).
Protein binding	Approximately 90% bound to albumin.
Volume of Distribution	0.8-1.2 L/kg, indicating extensive distribution into total body water.
Bioavailability	Oral: 60-70% due to first-pass metabolism.
Onset of Action	Oral: 1-2 hours; intravenous: within 5-10 minutes.
Duration of Action	Oral: 8-12 hours; intravenous: 6-8 hours. Duration may be extended in hepatic impairment.

Classification & Brands

Dosing & administration

100 mg orally twice daily

Dosage form	CAPSULE
Renal impairment	GFR 30-50 mL/min: 100 mg once daily; GFR <30 mL/min: 50 mg once daily; not recommended for GFR <15 mL/min
Liver impairment	Child-Pugh A: no adjustment; Child-Pugh B: 50 mg twice daily; Child-Pugh C: not recommended
Pediatric use	Not approved for pediatric use; no established dosing
Geriatric use	No specific adjustment; monitor renal function and consider reduced initial dose (50 mg twice daily) in patients >65 years with renal impairment

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for ANOQUAN (ANOQUAN).

Breastfeeding	Excreted in human milk. M/P ratio not determined. Avoid breastfeeding due to potential for serious adverse reactions in the nursing infant, including renal impairment and electrolyte disturbances.
Teratogenic Risk	Pregnancy Category X. Anoquan is contraindicated in all trimesters. In the first trimester, there is a high risk of major cardiac malformations and neural tube defects. Second and third trimester exposure is associated with fetal nephrotoxicity, oligohydramnios, and premature closure of the ductus arteriosus.

Warnings & precautions

■ FDA Black Box Warning

No FDA black box warning.

Side Effect Profile

Common Effects	Burning sensation Tingling Rash
Serious Effects

Absolute Contraindications

Known hypersensitivity to guanabenz; patients with severe hepatic or renal impairment.

Clinical Precautions

Precautions	Rebound hypertension upon abrupt discontinuation; sedation and drowsiness; potential for orthostatic hypotension; caution in patients with severe coronary insufficiency or cerebrovascular disease.
Food/Dietary	Avoid grapefruit and grapefruit juice as they may increase quinine levels. Take with a full glass of water. May be taken with meals to reduce nausea.

Clinical Tips & Counseling

Drug interactions

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Clinical Pearls	ANOQUAN (quinine sulfate) is used for uncomplicated Plasmodium falciparum malaria. Monitor for cinchonism (tinnitus, headache, nausea). Avoid in G6PD deficiency due to hemolysis risk. Correct hypoglycemia frequently. Use with caution in atrial fibrillation due to QT prolongation.
Patient Advice	Take with food to reduce gastrointestinal upset. · Complete full course even if symptoms improve. · Report ringing in ears, confusion, or vision changes. · Avoid driving if dizziness or visual disturbances occur. · Inform doctor of any history of G6PD deficiency or cardiac arrhythmias.