Generic Name: guanadrel (GWAH na drel)Brand Names: Hylorel
Guanadrel lowers blood pressure by decreasing the levels of certain chemicals in the blood. This allows the blood vessels (veins and arteries) to relax (widen).
Guanadrel is used to treat hypertension (high blood pressure).
Guanadrel may also be used for purposes other than those listed in this medication guide.
Use caution when rising from a sitting or lying position, especially first thing in the morning. Dizziness may occur while taking guanadrel and may result in a fall.
have congestive heart failure;
have pheochromocytoma; or
are taking a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate).
Before taking this medication, tell your doctor if you have
peptic ulcer disease (stomach ulcers);
You may require a dosage adjustment or special monitoring during treatment if you have any of the conditions listed above.Guanadrel is in the FDA pregnancy category B. This means that it is not expected to be harmful to an unborn baby. Do not take guanadrel without first talking to your doctor if you are pregnant or could become pregnant during treatment. Guanadrel passes into breast milk and it may be harmful to a nursing infant. Do not take guanadrel without first talking to your doctor if you are breast-feeding a baby.
Take guanadrel exactly as directed. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you.Take each dose with a full glass of water. Take guanadrel with food or milk if it causes stomach upset.
It is important to take guanadrel regularly to get the most benefit.Do not stop taking guanadrel suddenly without first talking to your doctor. This could cause severely high blood pressure, nervousness, and anxiety.
Your doctor may want you to have blood pressure monitoring or other medical evaluations during treatment with guanadrel to monitor progress and side effects.Store this medication at room temperature away from moisture and heat.
See also: Guanadrel dosage in more detail
Take the missed dose as soon as you remember. However, if it is almost time for the next dose, skip the dose you missed and take only the next regularly scheduled dose. Do not take a double dose of this medication.
Symptoms of a guanadrel overdose include low blood pressure (fainting, dizziness, weakness); a slow pulse; low body temperature; diarrhea; and slow breathing.
Use caution when rising from a sitting or lying position, especially first thing in the morning. Dizziness may occur while taking guanadrel and may result in a fall.Avoid alcohol while taking guanadrel. It may increase drowsiness an dizziness caused by guanadrel. Use caution even with small amounts of alcohol.
Guanadrel may increase the effects of other drugs that cause drowsiness, including antidepressants, alcohol, antihistamines, pain relievers, anxiety medicines, seizure medicines, and muscle relaxants. Dangerous sedation, dizziness, or drowsiness may occur if guanadrel is taken with any of these medications. Tell your doctor about all medicines that you are taking, and do not take any medicine without first talking to your doctor.
Avoid becoming overheated in hot weather or during exercise. Also avoid standing for long periods of time and use caution if you have a fever. These situations increase the effects of guanadrel in the body and may cause dizziness.
Before having surgery, tell your doctor or dentist that you are taking this medication.
an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives);
heart failure (shortness of breath, swelling of ankles or legs, sudden weight gain of 5 pounds or more); or
Other, less serious side effects are more likely to occur. Continue to take guanadrel and talk to your doctor if you experience
unusual fatigue or drowsiness;
dizziness (avoid standing up to quickly and use caution when performing hazardous activities);
anxiety, depression, or nightmares;
diarrhea, nausea, or vomiting (take guanadrel with food or milk if it upsets your stomach);
a stuffy nose or a dry mouth (sucking on ice chips or sugarless hard candy may relieve a dry mouth);
weight gain; or
Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.
Usual Adult Dose for Hypertension:
Initial dose: 10 mg/day orally in 1 to 2 divided doses.Maintenance dose: 20 to 75 mg/day orally in 2 to 4 divided doses.
Before taking guanadrel, tell your doctor if you are taking any of the following medicines:
a respiratory medicine such as albuterol (Ventolin, Proventil, Volmax, others), pirbuterol (Maxair), salmeterol (Serevent), and others;
a beta-blocker such as atenolol (Tenormin), acebutolol (Sectral), bisoprolol (Zebeta), carteolol (Cartrol), carvedilol (Coreg), labetalol (Trandate, Normodyne), metoprolol (Lopressor), nadolol (Corgard), propranolol (Inderal), pindolol (Visken), and timolol (Blocadren);
a phenothiazine such as chlorpromazine (Thorazine), prochlorperazine (Compazine), perphenazine (Trilafon), fluphenazine (Prolixin), thioridazine (Mellaril), and others;
other heart medications such as hydralazine (Apresoline) or minoxidil (Loniten); or
a tricyclic antidepressant such as amitriptyline (Elavil, Endep), imipramine (Tofranil), doxepin (Sinequan), nortriptyline (Pamelor), and others.
You may require special monitoring or a dosage adjustment if you are taking any of the medicines listed above.
Guanadrel may increase the effects of other drugs that cause drowsiness, including antidepressants, alcohol, antihistamines, sedatives (used to treat insomnia), pain relievers, anxiety medicines, seizure medicines, and muscle relaxants. Tell your doctor about all medicines that you are taking, and do not take any medicine without first talking to your doctor.
Drugs other than those listed here may also interact with guanadrel or affect your condition. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines, including vitamins, minerals, and herbal products.
Guanadrel is available with a prescription under the brand name Hylorel. Other brand or generic formulations may also be available. Ask your pharmacist any questions you have about this medication, especially if it is new to you.
Hylorel 10 mg--light-orange, elliptical, scored tablets
Hylorel 25 mg--white, elliptical, scored tablets