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Guanadrel sulfate oral

Important Note

The following information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist or other healthcare professional. It should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. Consult your healthcare professional before using this drug.





This medication relaxes and dilates (expands) blood vessels resulting in lowered blood pressure. It is used to treat hypertension (high blood pressure).

How To Use

Take this medication exactly as prescribed. Try to take it at the same time(s) each day. This medication may be taken with food if stomach irritation occurs. It is important to continue taking this medication even if you feel well. Most people with high blood pressure do not feel sick.

Side Effects

Dizziness, drowsiness, headache, constipation, diarrhea, gas pains, loss of appetite, fatigue, and nasal congestion may occur as your body adjusts to the medication. If these symptoms persist or become bothersome, notify your doctor. Inform your doctor if you develop: chest pain, shortness of breath, skin rash, swelling of the hands or feet, blurred vision, yellowing of the eyes or skin. If you notice other effects not listed above, contact your doctor or pharmacist.


Tell your doctor your medical history, especially of: heart or blood vessel disease, stomach ulcers, diarrhea, pheochromocytoma, asthma, fever, allergies (especially drug allergies). This medication should be used only when clearly needed during pregnancy. It is not known if guanadrel passes into breast milk. Consult with your doctor before breast-feeding. To avoid dizziness and lightheadedness when rising from a seated or lying position, change positions slowly. Avoid prolonged standing and be careful on stairs. Limit your intake of alcoholic beverages while taking this medication. Alcohol can lead to excessive drowsiness or fainting. Also avoid hot showers, saunas, or prolonged exercise as excessive heat can worsen dizziness.

Drug Interactions

Tell your doctor of all medications you use (both prescription and nonprescription), especially of: antidepressants, MAO inhibitors (e.g., furazolidone, linezolid, moclobemide, phenelzine, selegiline, tranylcypromine), drugs used for mental or emotional conditions (haloperidol, loxapine, or phenothiazines such as chlorpromazine), drugs used for diabetes, high blood pressure medications, drugs used to promote weight loss. Do not take any medication for coughs, colds or allergies without first checking with your doctor or pharmacist. Some of these products contain ingredients which can increase blood pressure (e.g., phenylephrine, pseudoephedrine). Do not start or stop any medicine without doctor or pharmacist approval.


If overdose is suspected, contact your local poison control center or emergency room immediately. Symptoms of overdose may include nausea, vomiting, unusual dizziness, blurred vision, fainting, and loss of consciousness.


It is important to have your blood pressure checked regularly while taking this medication. Learn how to monitor your blood pressure. Discuss this with your doctor. Do not allow anyone else to take this medication.

Missed Dose

If you miss a dose, take as soon as remembered; do not take if it is almost time for the next dose, instead, skip the missed dose and resume your usual dosing schedule. Do not "double-up" the dose to catch up. Contact your doctor if 2 or more consecutive doses are missed.


Store at room temperature away from sunlight and moisture.

Medical Alert

Your condition can cause complications in a medical emergency. For enrollment information call MedicAlert at 1-800-854-1166 (USA), or 1-800-668-1507 (Canada).