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Generic Name: guanfacine (GWAHN-fa-seen)
Brand Name: Tenex

Tenex 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.

Tenex is an alpha agonist. It works by relaxing (dilating) blood vessels and decreasing heart rate, which lowers blood pressure.

Do NOT use Tenex if:

  • you are allergic to any ingredient in Tenex

Contact your doctor or health care provider right away if any of these apply to you.

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Before using Tenex:

Some medical conditions may interact with Tenex. 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 liver problems or kidney problems
  • if you have a history of low blood pressure, dizziness when you stand up, heart problems (eg, heart block, recent heart attack, slow or irregular heartbeat), blood vessel problems (eg, in the brain or heart), or fainting
  • if you are dehydrated or will be exposed to high temperatures
  • if you are scheduled for surgery

Some MEDICINES MAY INTERACT with Tenex. Tell your health care provider if you are taking any other medicines, especially any of the following:

  • Phenytoin because it may decrease Tenex's effectiveness and increase the risk of certain side effects
  • Barbiturates (eg, phenobarbital), benzodiazepines (eg, diazepam), phenothiazines (eg, chlorpromazine) because the risk of their side effects may be increased by Tenex

This may not be a complete list of all interactions that may occur. Ask your health care provider if Tenex 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 Tenex:

Use Tenex as directed by your doctor. Check the label on the medicine for exact dosing instructions.

  • Take Tenex by mouth with or without food.
  • Do not suddenly stop taking Tenex. You may have an increased risk of side effects. If you need to stop Tenex, your doctor will gradually lower your dose.
  • Tenex works best if it is taken at the same time each day.
  • Continue to use Tenex even if you feel well. Do not miss any doses.
  • If you miss a dose of Tenex, 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.

Ask your health care provider any questions you may have about how to use Tenex.

Important safety information:

  • Tell your doctor or dentist that you take Tenex before you receive any medical or dental care, emergency care, or surgery.
  • Tenex may cause drowsiness, dizziness, or light-headedness. These effects may be worse if you take it with alcohol or certain medicines. Use Tenex with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
  • Do not drink alcohol while you are taking Tenex.
  • Talk with your doctor before you use medicines that may cause drowsiness (eg, sleep aids, muscle relaxers) while you are using Tenex; it may add to their effects. Ask your pharmacist if you have questions about which medicines may cause drowsiness.
  • Tenex may cause dizziness, light-headedness, or fainting; alcohol, hot weather, exercise, or fever may increase these effects. To prevent them, sit up or stand slowly, especially in the morning. Sit or lie down at the first sign of any of these effects.
  • Do NOT take more than the recommended dose without checking with your doctor.
  • Do not become overheated or dehydrated in hot weather or while you are being active; the risk of low blood pressure or fainting may be increased.
  • You will need to have your heart rate and blood pressure checked often. Talk with your doctor.
  • PREGNANCY and BREAST-FEEDING: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Tenex while you are pregnant. It is not known if this medicine is found in breast milk. If you are or will be breast-feeding while you use Tenex, check with your doctor. Discuss any possible risks to your baby.

If you suddenly stop taking Tenex, you may experience WITHDRAWAL symptoms, including nervousness, agitation, headache, tremor, and rapid increase in blood pressure.

Possible side effects of Tenex:

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:

Constipation; dizziness; drowsiness; dry mouth; headache; tiredness; weakness.

Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); fainting; inability to have sex; severe or persistent dizziness, drowsiness, or weakness; slow or irregular heartbeat.

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.

Proper storage of Tenex:

Store Tenex between 68 and 77 degrees F (20 and 25 degrees C). Store away from heat, moisture, and light. Do not store in the bathroom. Keep Tenex out of the reach of children and away from pets.

General information:

  • If you have any questions about Tenex, please talk with your doctor, pharmacist, or other health care provider.
  • Tenex 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 Tenex 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 Tenex. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to Tenex. 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 Tenex.

Issue Date: June 3, 2015
Database Edition 15.2.1.003
Copyright © 2015 Clinical Drug Information, LLC

Disclaimer: This information should not be used to decide whether or not to take this medicine 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 this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. 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 this medicine.

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