Jeffrey Panko NP Psychiatry · Patient education
Guanfacine
Intuniv extended-release / Tenex or generic immediate-release tablets
A guide for adults taking guanfacine.
Follow the directions on your prescription and your provider's recommendations.
Formulations: Immediate-release and extended-release tablets are not interchangeable milligram for milligram. Switching requires a new schedule.
What it is used for
Extended-release guanfacine is used for ADHD, alone or with a stimulant; the U.S. evidence and labeling primarily concern children and adolescents. Adult ADHD treatment is generally off-label. Immediate-release guanfacine is approved for high blood pressure.
How it works
It stimulates alpha-2A receptors involved in attention and regulation of arousal. It also reduces signals that maintain blood pressure and pulse.
What to expect over time
Sedation and blood-pressure effects may appear early. Attention or impulse-control benefit is assessed over several weeks while the dose is adjusted.
Taking your medication
- Swallow ER tablets whole; do not break, crush, or chew.
- Take ER once daily as prescribed and avoid taking it with a high-fat meal.
- Do not double a missed dose. After two or more consecutive missed doses, contact your provider before restarting.
- Do not stop suddenly; a gradual reduction helps prevent rebound high blood pressure.
When to get help
Emergency symptoms. Get emergency care for collapse, severe breathing difficulty, or severe headache with chest pain or neurologic symptoms after stopping.
Prompt medical advice. Report fainting, persistent dizziness, an unusually slow pulse, or excessive sedation. Contact your provider if illness prevents regular dosing.
If you feel unsafe or have thoughts of self-harm, call 911 or go to an emergency department.
Possible side effects
- Sleepiness or fatigue
- Dizziness or low blood pressure
- Dry mouth, constipation, or headache
- Slow pulse
Keeping track of treatment
Some side effects resolve with time; others may require a change of medication. Discuss persistent or bothersome side effects with your provider.
Have blood pressure and pulse checked before treatment, after dose increases, and periodically. Track alertness, falls, sleep, and the ADHD symptoms being treated.
If you take too much
For a suspected overdose, call Poison Control at 1-800-222-1222 immediately, even if you feel well. Call 911 for a seizure, collapse, trouble breathing, or inability to wake.
Before you start
Discuss fainting, low blood pressure, slow pulse, heart block, and kidney or liver problems. Avoid dehydration and overheating.
Discuss pregnancy, pregnancy plans, and breastfeeding with your provider. Treatment decisions should consider both the medication and the condition being treated.
Medicines and interactions
Review all your medications with your provider, including over-the-counter medicines and supplements. Have new medications checked before taking them.
CYP3A inhibitors or inducers can require a dose adjustment. Review grapefruit, certain antibiotics or antifungals, and seizure medicines.
Alcohol and other sedatives increase impairment. Blood-pressure or heart-rate medicines can add low pulse or fainting.
Everyday tips
Plan refills early and keep a record of missed doses.
Stand up slowly and avoid driving when drowsy.
Your questions answered
Can I stop once ADHD symptoms improve?
Consult with your provider. Sudden stopping can raise blood pressure even when the medication was prescribed for ADHD.
Can I use my old immediate-release dose instead?
No. The release patterns differ, so a switch requires specific instructions.
Storage and safety
Keep medication in its labeled container, away from excess heat and moisture and out of reach of children and pets. Do not share it. Ask a pharmacy about disposal of unused medication.
Sources
About this information
Educational handout; does not replace your prescription or provider's recommendations.
Educational inclusion does not mean this medication or its indications are treated at this practice. Review the guide for your exact product with your prescriber or pharmacist.