Guanabenz (Oral)

Guanabenz is part of a group of medicines called antihypertensives. It is used to treat high blood pressure (hypertension).

High blood pressure makes the heart and arteries work harder. If it lasts for a long time, the heart and arteries may not work properly. This can harm the blood vessels in the brain, heart, and kidneys, leading to a stroke, heart failure, or kidney failure. High blood pressure can also increase the chance of heart attacks. Controlling blood pressure can help reduce these risks.

Guanabenz works by controlling nerve signals along specific nerve pathways. This helps relax blood vessels, allowing blood to flow through them more easily. This helps lower blood pressure.

Guanabenz is available only with your doctor's prescription.

It is important that your doctor check your progress at regular visits to make sure that this medicine is working properly.

Check with your doctor before you stop taking guanabenz. Your doctor may want you to gradually reduce the amount you are taking before stopping completely.

Before having any kind of surgery (including dental surgery) or emergency treatment, inform the medical doctor or dentist in charge that you are using this medicine.

Do not take other medicines unless they have been discussed with your doctor. This especially includes over-the-counter (nonprescription) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems, as they may increase your blood pressure.

Guanabenz will enhance the effects of alcohol and other CNS depressants (medicines that slow down the nervous system, possibly causing drowsiness). Some examples of CNS depressants are antihistamines or medicines for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates; medicines for seizures; muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are using this medicine.

Guanabenz may cause some people to feel dizzy, drowsy, or less alert than usual. Make sure you know how you react to this medicine before driving, using machines, or doing anything else that could be dangerous if you are dizzy or not alert.

Guanabenz may cause dryness of the mouth, nose, and throat. For temporary relief of mouth dryness, use sugarless candy or gum, melt bits of ice in your mouth, or use a saliva substitute. However, if your mouth continues to feel dry for more than 2 weeks, consult your medical doctor or dentist. Continuing dryness of the mouth may increase the risk of dental disease, including tooth decay, gum disease, and fungal infections.

In deciding to use a medicine, you and your doctor should think about the risks and benefits. For this medicine, consider the following:

Allergies

Inform your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also, tell your healthcare professional if you have any other allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Studies on this medicine have only been conducted in adults, so there is no specific information about using guanabenz in children compared to other age groups.

Geriatric

Many medicines have not been specifically studied in older adults. Therefore, it may not be known if they work the same way as in younger adults or if they cause different side effects in older people. There is no specific information about using guanabenz in the elderly compared to other age groups. However, older adults may be more likely to experience dizziness, faintness, or drowsiness because they are usually more sensitive to the effects of guanabenz.

Breast Feeding

There are no adequate studies in women to determine the risk to infants when using this medication while breastfeeding. Weigh the potential benefits against the potential risks before taking this medication during breastfeeding.

Interactions with Medicines

Some medicines should not be used together at all, while others may be okay to use together even if there might be an interaction. In these cases, your doctor may need to adjust the dose or take other precautions. It is especially important for your healthcare professional to know if you are taking any of the medicines listed below. The following interactions have been selected based on their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Iobenguane I 131

Using this medicine with any of the following medicines may increase the risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Yohimbine

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be taken at or around the time of eating food or certain types of food because interactions may occur. Using alcohol or tobacco with certain medicines may also lead to interactions. Discuss with your healthcare professional about how to use your medicine with food, alcohol, or tobacco.

Other Medical Problems

Having other medical problems may affect your use of this medicine. Make sure to tell your doctor if you have any other medical issues, especially:

• Heart or blood vessel disease—Lowering blood pressure may worsen some conditions

• Kidney disease or
• Liver disease—The effects of guanabenz may be stronger due to slower removal of guanabenz from the body

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do, they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

Signs and symptoms of overdose

• Dizziness (severe)
• irritability
• nervousness
• pinpoint pupils
• slow heartbeat
• unusual tiredness or weakness

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

• Dizziness
• drowsiness
• dryness of mouth
• weakness

Less common or rare

• Decreased sexual ability
• headache
• nausea

After you stop using this medicine, it may still produce some side effects that need attention. During this time, check with your doctor immediately if you notice the following side effects:

• Anxiety or tenseness
• chest pain
• fast or irregular heartbeat
• headache
• increased salivation
• increase in sweating
• nausea or vomiting
• nervousness or restlessness
• shaking or trembling of hands or fingers
• stomach cramps
• trouble sleeping

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

In the U.S.

• Wytensin

Pharmacologic Class: Alpha-2 Adrenergic Agonist

In addition to the use of the medicine your doctor has prescribed, treatment for your high blood pressure may include weight control and care in the types of foods you eat, especially foods high in sodium. Your doctor will tell you which of these are most important for you. You should check with your doctor before changing your diet.

Many patients who have high blood pressure will not notice any signs of the problem. In fact, many may feel normal. It is very important that you take your medicine exactly as directed and that you keep your appointments with your doctor even if you feel well.

Remember that this medicine will not cure your high blood pressure but it does help control it. Therefore, you must continue to take it as directed if you expect to lower your blood pressure and keep it down. You may have to take high blood pressure medicine for the rest of your life. If high blood pressure is not treated, it can cause serious problems such as heart failure, blood vessel disease, stroke, or kidney disease.

To help you remember to take your medicine, try to get into the habit of taking it at the same time each day.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For oral dosage form (tablets): For high blood pressure: Adults—At first, 4 milligrams (mg) two times a day. Then, your doctor may gradually increase your dose. Children—Use and dose must be determined by your doctor.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

If you miss two or more doses in a row, check with your doctor. If your body suddenly goes without this medicine, some unpleasant effects may occur. If you have any questions about this, check with your doctor.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.