guanfacine

General information

• Primary label indications include: Hypertension (label).
• Class: Adjunctive therapy
• Common US brands: TENEX
• Typical dose range: Hypertension labeling: start 1 mg once daily at bedtime to minimize somnolence; if response is inadequate after 3–4 weeks, 2 mg once daily may be used (label).
• Therapeutic drug monitoring not routinely recommended.
• Last reviewed: 2025-12-30

Dosing & forms

• Forms/strengths: Immediate-release oral tablets: 1 mg, 2 mg (label).
• Frequency: Hypertension labeling: start 1 mg once daily at bedtime to minimize somnolence; if response is inadequate after 3–4 weeks, 2 mg once daily may be used (label).
• Typical range: Hypertension labeling: start 1 mg once daily at bedtime to minimize somnolence; if response is inadequate after 3–4 weeks, 2 mg once daily may be used (label).

Mechanism (brief)

Alpha-2A adrenergic agonist (centrally acting antihypertensive; sometimes used off-label as a psychiatric adjunct).

Metabolism & Half‑life

• Metabolism: Hepatic oxidative metabolism
• Half‑life: Single-dose mean 17 h; Single-dose range 10–30 h

Therapeutic Drug Monitoring (TDM)

Recommended: No

Monitoring highlights

• Baseline and periodic blood pressure and heart rate, especially during titration.
• Sedation, dizziness, and orthostasis; reassess driving, falls risk, and daytime functioning.
• Review co-prescribed antihypertensives and sedatives at initiation and dose changes.
• Document a taper plan early to reduce abrupt discontinuation and rebound hypertension risk.

Sources

• Guanfacine tablets prescribing information — DailyMed (2025)
• Attention deficit hyperactivity disorder (NICE guideline NG87) — NICE (2018)
• Clinical Practice Guideline for the Diagnosis, Evaluation, and Treatment of Attention-Deficit/Hyperactivity Disorder in Children and Adolescents — Pediatrics (2019)
• Comparative efficacy and tolerability of medications for ADHD (systematic review and network meta-analysis) — Lancet Psychiatry (2018)