The originating document has been archived. We cannot confirm the completeness, accuracy and currency of the content.
Generic Name: guanabenz (GWAHN-a-benz)
Brand Name: Generic only. No brands available.
Guanabenz is used for:
Treating high blood pressure. It may be used alone or with other medicines. It may also be used for other conditions as determined by your doctor.
Guanabenz is an alpha agonist. It works by relaxing (dilating) blood vessels and decreasing heart rate, which lowers blood pressure.
Do NOT use guanabenz if:
- you are allergic to any ingredient in guanabenz
Contact your doctor or health care provider right away if any of these apply to you.
Before using guanabenz:
Some medical conditions may interact with guanabenz. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:
- if you are pregnant, planning to become pregnant, or are breast-feeding
- if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
- if you have allergies to medicines, foods, or other substances
- if you have severe kidney or liver problems or the blood disorder porphyria
- if you have blood vessel disease affecting the brain, heart problems, or have had a stroke or a recent heart attack
- if you are scheduled for surgery
Some MEDICINES MAY INTERACT with guanabenz. Tell your health care provider if you are taking any other medicines, especially any of the following:
- Beta-blockers (eg, propranolol), calcium channel blockers (eg, verapamil), or digitalis because a severe decrease in heart rate may occur
- Tricyclic antidepressants (eg, amitriptyline) because the effectiveness of guanabenz may be decreased and certain side effects may be increased
This may not be a complete list of all interactions that may occur. Ask your health care provider if guanabenz may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.
How to use guanabenz:
Use guanabenz as directed by your doctor. Check the label on the medicine for exact dosing instructions.
- Guanabenz may be taken with or without food.
- Guanabenz works best if it is taken at the same time each day.
- Continue to use guanabenz even if you feel well. Do not miss any doses.
- Do not suddenly stop taking guanabenz without talking to your doctor. Excessive elevations in blood pressure and symptoms such as nervousness, headache, and confusion may occur if guanabenz is suddenly stopped.
- If you miss a dose of guanabenz, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once. If you miss 2 or more doses in a row, contact your doctor.
Ask your health care provider any questions you may have about how to use guanabenz.
Important safety information:
- Guanabenz may cause drowsiness, dizziness, or lightheadedness. Do not drive, operate machinery, or do anything else that could be dangerous until you know how you react to guanabenz. Using guanabenz alone, with certain other medicines, or with alcohol may lessen your ability to drive or to perform other potentially dangerous tasks.
- Avoid drinking alcohol or taking other medications that cause drowsiness (eg, sedatives, tranquilizers) while taking guanabenz. Guanabenz will add to the effects of alcohol and other depressants. Ask your pharmacist if you have questions about which medicines are depressants.
- Guanabenz may cause dizziness, lightheadedness, or fainting. Alcohol, hot weather, exercise, and fever can increase these effects. To prevent them, sit up or stand slowly, especially in the morning. Also, sit or lie down at the first sign of dizziness, lightheadedness, or weakness.
- Patients being treated for high blood pressure often feel tired or run down for a few weeks after beginning therapy. Continue taking your medication even though you may not feel quite "normal". Contact your doctor or pharmacist about any new symptoms.
- If you experience dry mouth, use sugarless candy or gum, or melt bits of ice in your mouth to help keep your mouth moist.
- Before having any surgical or dental procedures or receiving emergency treatment, tell the doctor or dentist in charge that you are receiving guanabenz.
- LAB TESTS, including blood pressure, may be performed to monitor your progress or to check for side effects. Be sure to keep all doctor and lab appointments.
- Use guanabenz with caution in the ELDERLY because they may be more sensitive to its effects, especially dizziness.
- Use guanabenz with extreme caution in CHILDREN younger than 12 years of age. Safety and effectiveness in this age group have not been confirmed. Also, CHILDREN who are sick and vomiting may be more sensitive to developing withdrawal symptoms.
- PREGNANCY and BREAST-FEEDING: If you plan on becoming pregnant, discuss with your doctor the benefits and risks of using guanabenz during pregnancy. It is unknown if guanabenz is excreted in breast milk. If you are or will be breast-feeding while you are using guanabenz, check with your doctor or pharmacist to discuss the risks to your baby.
If you suddenly stop taking guanabenz, you may experience WITHDRAWAL symptoms, including nervousness, agitation, headache, tremor, and rapid increase in blood pressure.
Possible side effects of guanabenz:
All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:
Seek medical attention right away if any of these SEVERE side effects occur:
Constipation; dizziness; drowsiness; dry mouth; tiredness.
Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); changes in heartbeat; inability to have sex; pounding in the chest.
This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. To report side effects to the appropriate agency, please read the Guide to Reporting Problems to FDA.
If OVERDOSE is suspected:
Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center, or emergency room immediately. Accidental overdose of guanabenz is an increasing cause of poisoning in children 3 years of age and younger. Symptoms may include difficult or slow breathing; drowsiness leading to unresponsiveness or coma; irritability; lightheadedness, especially upon standing; pinpoint pupils; slow heartbeat; vomiting; weakness.Proper storage of guanabenz:
Store guanabenz at room temperature, between 59 and 86 degrees F (15 and 30 degrees C). Store away from heat, moisture, and light. Do not store in the bathroom. Keep guanabenz out of the reach of children and away from pets.
- If you have any questions about guanabenz, please talk with your doctor, pharmacist, or other health care provider.
- Guanabenz is to be used only by the patient for whom it is prescribed. Do not share it with other people.
- If your symptoms do not improve or if they become worse, check with your doctor.
- Check with your pharmacist about how to dispose of unused medicine.
This information should not be used to decide whether or not to take guanabenz or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about guanabenz. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to guanabenz. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using guanabenz.