GWAHN-fa-seen 
Contraindicated in:
Use Cautiously in:
CV: bradycardia, chest pain, hypotension, palpitations, rebound hypertension, syncope.
EENT: tinnitus.
GI: constipation, dry mouth, abdominal pain, nausea.
GU: erectile dysfunction.
Neuro: drowsiness, headache, weakness, depression, dizziness, fatigue, insomnia, irritability.
Resp: dyspnea.
Drug-Drug:
(Generic available)
Hypertension
ADHD
Intuniv, Tenex
Therapeutic Classification: antihypertensives, agents for attention deficit disorder
Pharmacologic Classification:
Absorption: Immediate-release is well absorbed (80%); extended-release has lower rate and extent of absorption (↑ absorption with high-fat meals).
Distribution: Appears to be widely distributed.
Metabolism/Excretion: 50% metabolized by the liver, 50% excreted unchanged by the kidneys.
Half-life: 17 hr.
(antihypertensive effect)
| ROUTE | ONSET | PEAK | DURATION |
|---|---|---|---|
| PO (single dose) | unknown | 8–12 hr | 24 hr |
| PO (multiple doses) | within 1 wk | 1–3 mo | unknown |
NDC Code*