Alterations in taste Contraindications Hypersensitivity Cautions Avoid abrupt withdrawal (can result in anxiety, nervousness, and rebound hypertension) May cause hypotension, orthostasis, bradycardia, and syncope, use with caution in history of cerebrovascular disease, recent MI, severe coronary insufficiency, or syncope Chronic renal/hepatic failure May cause sedation, especially at start; avoid operating heavy machinery Skin rash with exfoliation reported Avoid concomitant use with other CNS depressants (eg, alcohol) as they may potentiate CNS effects Risk of cardiovascular effects may increase when administered concurrently with antihypertensive medications or drugs that affect heart rate In post marketing experience, abrupt discontinuation of the extended-release tablets has resulted in clinically significant and persistent rebound hypertension above baseline levels and increases in heart rate; hypertensive encephalopathy reported in association with rebound hypertension with guanfacine ADHD Hypotension is dose-limiting Do not substitute extended-release tablet for immediate-release guanfacine on a mg/mg basis, because of differing pharmacokinetic profiles May cause dose-dependent hypotension, bradycardia, and syncope Hallucinations reported in children with ADHD treated with guanfacine Geriatric patients May cause adverse CNS effects May cause bradycardia and orthostatic hypotension Not recommended as routine treatment for hypertension (Beers criteria) Pregnancy There is pregnancy exposure registry that monitors pregnancy outcomes in women exposed to ADHD medications, during pregnancy; healthcare providers are encouraged to register patients by calling National Pregnancy Registry for ADHD Medications at 1-866-961-2388. Available data with guanfacine over decades of use in pregnant women have not identified a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes; however, use of guanfacine in pregnant women over this time has been infrequent; Animal data In animal reproduction studies, rabbits and rats exposed to 3 and 4 times the maximum recommended human dose (MRHD), respectively, showed no adverse outcomes. However, higher doses were associated with reduced fetal survival and maternal toxicity Lactation There are no data on presence of guanfacine in human milk or effects on breastfed infant; effects on milk production are also unknown; drug is present in milk of lactating rats; if drug is present in animal milk, it is likely that drug will be present in human milk; if an infant is exposed to drug through breastmilk, monitor for symptoms of hypotension and bradycardia such as sedation, lethargy and poor feeding; the developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for drug and any potential adverse effects on breastfed child from therapy or from underlying maternal condition. Monitor breastfeeding infants exposed to guanfacine through breastmilk for sedation, lethargy, and poor feedingPregnancy Categories A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk. B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available. Mechanism of Action Selective alpha2-adrenergic receptor agonist causing decreased sympathetic outflow and subsequent decrease in vasomotor tone and heart rate; may preferentially bind postsynaptic alpha2A adrenoreceptors in the prefrontal cortex, which may improve delay-related firing of prefrontal cortex neurons (as a result, behavioral inhibition may be affected); mechanism of action in ADHD is not known Absorption AUC: 56 ng·hr/mL (immediate release tablets); 32 ng·hr/mL (extended release tablets) Peak plasma concentration: 2.5 ng/mL (Immediate release tablets); 1 ng/mL (extended release tablets) Peak plasma time: 3 hr (immediate release tablets); 6 hr (extended release tablets) Bioavailability: 80-100% (immediate release tablets); 58% (extended release tablets) Onset: Initial effect (2 hr); maximum effect (6 hr) Duration: 24 hr Distribution Protein bound: 70% Vd: 6.3 L/kg Metabolism Via CYP3A4 (hepatic) Metabolites: Glucuronide and sulfate of 3-hydroxy guanfacine, oxidized mercapturic acid derivatives (inactive) Elimination Half-life: 16 hr (immediate release tablets); 18 hr (extended release tablets) Dialyzable: HD (No) Excretion: Urine 80% (unchanged) Oral Administration Administer orally once a day Extended-release tablets Do not administer with high-fat meals due to potential for increased serum levels Swallow tablets whole; do not crush, chew, or break tablets because this will increase the rate of guanfacine release Missed dose: Repeat dosage titration based on patient tolerability Storage Immediate-release tablets: at 20-25°C (68-77°F); dispense in a tight, light-resistant container Extended-release tablets: Store at 20-25°C (68-77°F); excursions permitted to 15-30°C (59-86°F) BRAND FORM. UNIT PRICE PILL IMAGE guanfacine oral- 1 mg tabletguanfacine oral- 4 mg tabletguanfacine oral- 3 mg tabletguanfacine oral- 1 mg tabletguanfacine oral- 3 mg tabletguanfacine oral- 2 mg tabletguanfacine oral- 1 mg tabletguanfacine oral- 2 mg tabletguanfacine oral- 1 mg tabletguanfacine oral- 1 mg tabletguanfacine oral- 2 mg tabletguanfacine oral- 1 mg tabletguanfacine oral- 2 mg tabletguanfacine oral- 1 mg tabletguanfacine oral- 2 mg tabletguanfacine oral- 4 mg tabletguanfacine oral- 3 mg tabletguanfacine oral- 4 mg tabletguanfacine oral- 3 mg tabletguanfacine oral- 2 mg tabletguanfacine oral- 4 mg tabletguanfacine oral- 1 mg tabletguanfacine oral- 3 mg tabletguanfacine oral- 2 mg tabletguanfacine oral- 1 mg tabletguanfacine oral- 2 mg tabletguanfacine oral- 1 mg tabletguanfacine oral- 2 mg tabletguanfacine oral- 1 mg tabletguanfacine oral- 3 mg tabletguanfacine oral- 4 mg tabletguanfacine oral- 2 mg tabletguanfacine oral- 2 mg tabletguanfacine oral- 2 mg tabletguanfacine oral- 1 mg tabletIntuniv ER oral- 4 mg tabletIntuniv ER oral- 3 mg tabletIntuniv ER oral- 2 mg tabletIntuniv ER oral- 1 mg tabletCopyright © 2010 First DataBank, Inc.Print Patient Educationguanfacine oral GUANFACINE - ORAL (GWAN-fuh-seen) COMMON BRAND NAME(S): Tenex USES: This medication is used alone or with other medications to treat high blood pressure (hypertension). Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. Guanfacine acts in the brain. It decreases certain nerve signals from the brain to the blood vessels and the heart. This causes the blood vessels to relax so that blood can flow more easily and also slows the heart rate. These effects help to lower blood pressure. HOW TO USE: Take this medication by mouth with or without food as directed by your doctor, usually once daily at bedtime.The dosage is based on your medical condition, response to treatment, and other medications you may be taking. Be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day.It may take several weeks before you get the full benefit of this medication. Keep taking this medication even if you feel well. Most people with high blood pressure do not feel sick.Do not stop taking this medication without consulting your doctor. Some conditions may become worse when this drug is suddenly stopped. Also, you may experience symptoms such as headache, nervousness, agitation, tremor, fast heartbeat, and high blood pressure. To prevent these symptoms while you are stopping treatment with this drug, your doctor may reduce your dose gradually. Ask your doctor or pharmacist for more details. Report any new or worsening symptoms right away.Tell your doctor if your condition does not improve or if it worsens (for example, your routine blood pressure readings remain high or increase). SIDE EFFECTS: Dry mouth, drowsiness, dizziness, constipation, tiredness, and weakness may occur. Decreased sexual ability has been reported rarely. If any of these effects last or get worse, tell your doctor or pharmacist promptly.To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water, or use a saliva substitute.To lower your risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: fast/slow heartbeat, fainting, mental/mood changes (such as depression, hallucinations, confusion, thoughts of suicide).A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345. PRECAUTIONS: Before taking guanfacine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, liver disease, personal/family history of mental/mood disorders (such as bipolar disorder, depression, suicidal thoughts).This drug may make you dizzy or drowsy. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Children may be more sensitive to the side effects of this drug, especially hallucinations and mental/mood changes.Older adults may be more sensitive to the side effects of this drug, especially dizziness (more likely when standing up), drowsiness, slow heartbeat, or depression. Dizziness and drowsiness can increase the risk of falling.During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.It is unknown if this medication passes into breast milk. Consult your doctor before breast-feeding. DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Tell your doctor or pharmacist if you are taking other products that cause drowsiness including alcohol, marijuana (cannabis), antihistamines (such as cetirizine, diphenhydramine), drugs for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), and opioid pain relievers (such as codeine, hydrocodone).Check the labels on all your medicines (such as cough-and-cold products, diet aids, nonsteroidal anti-inflammatory drugs-NSAIDs such as ibuprofen for pain/fever reduction) because they may contain ingredients that cause drowsiness or could increase your blood pressure or heart rate. Ask your pharmacist about using those products safely. OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: severe drowsiness, severe dizziness, severe tiredness, very slow heartbeat. NOTES: Do not share this medication with others.Talk with your doctor about making changes to your lifestyle that may help this medication work better (such as stress reduction programs, exercise, and dietary changes).Have your blood pressure and heart rate checked regularly while taking this medication. Learn how to check your own blood pressure and heart rate at home, and share the results with your doctor. MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up. STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it