Hylorel (patient information)
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
What is Hylorel (guanadrel)?
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.
What is the most important information I should know about Hylorel (guanadrel)?
Do not stop taking guanadrel suddenly without first talking to your doctor. This could cause severely high blood pressure, nervousness, and anxiety. Use caution when driving, operating machinery, or performing other hazardous activities. Guanadrel may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities.
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.
What should I discuss with my healthcare provider before taking Hylorel (guanadrel)?
Do not take guanadrel without first talking to your doctor if you have
- congestive heart failure;
- have pheochromocytoma; or
- 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);
- ulcerative colitis;
- kidney disease; or
- asthma.
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.
How should I take Hylorel (guanadrel)?
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. What happens if I miss a dose?
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.
What happens if I overdose?
Seek emergency medical attention if an overdose is suspected.
Symptoms of a guanadrel overdose include
- low blood pressure (fainting, dizziness, weakness);
- a slow pulse;
- low body temperature;
- diarrhea; and
- slow breathing.
What should I avoid while taking Hylorel (guanadrel)?
Use caution when driving, operating machinery, or performing other hazardous activities. Guanadrel may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities.
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.
Hylorel (guanadrel) side effects
If you experience any of the following serious side effects, stop taking guanadrel and seek emergency medical attention or contact your doctor immediately:
- an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives);
- irregular heartbeats;
- heart failure (shortness of breath, swelling of ankles or legs, sudden weight gain of 5 pounds or more); or
- chest pain.
- 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);
- blurred vision;
- weight gain; or
- impotence or difficulty ejaculating.
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.
What other drugs will affect Hylorel (guanadrel)?
Do not take guanadrel without first talking to your doctor if you have taken a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate) in the last 14 days
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.
Where can I get more information?
Your pharmacist has additional information about guanadrel written for health professionals that you may read.
What does my medication look like?
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