GUANABENZ (Systemic)?
Some commonly used brand names are:
In the U.S.?
? Not commercially available in Canada.
Category
Description
Guanabenz (GWAHN-a-benz) belongs to the generalclass of medicines called antihypertensives. It is used to treat high bloodpressure (hypertension).
High blood pressure adds to the work load of the heart and arteries. Ifit continues for a long time, the heart and arteries may not function properly.This can damage the blood vessels of the brain, heart, and kidneys, resultingin a stroke, heart failure, or kidney failure. High blood pressure may alsoincrease the risk of heart attacks. These problems may be less likely to occurif blood pressure is controlled.
Guanabenz works by controlling nerve impulses along certain nerve pathways.As a result, it relaxes blood vessels so that blood passes through them moreeasily. This helps to lower blood pressure.
Guanabenz is available only with your doctor's prescription, in the followingdosage form:
Before Using This Medicine
In deciding to use a medicine,the risks of taking the medicine must be weighed against the good it willdo. This is a decision you and your doctor will make. For guanabenz, the followingshould be considered:
Allergies?Tell your doctor if you have ever had any unusual orallergic reaction to guanabenz. Also tell your health care professional ifyou are allergic to any other substance, such as foods, preservatives, ordyes.
Pregnancy?Guanabenz has not been studied in pregnant women.However, studies in rats have shown that guanabenz given in doses 9 to 10times the maximum human dose caused a decrease in fertility. In addition,3 to 6 times the maximum human dose caused birth defects (in the skeleton)in mice, and 6 to 9 times the maximum human dose caused death of the fetusin rats. Before taking this medicine, make sure your doctor knows if you arepregnant or if you may become pregnant.
Breast-feeding?It is not known whether guanabenz passes into thebreast milk. However, this medicine has not been reported to cause problemsin nursing babies.
Children?Studies on this medicine have been done only in adultpatients, and there is no specific information comparing use of guanabenzin children with use in other age groups.
Older adults?Many medicines have not been studied specificallyin older people. Therefore, it may not be known whether they work exactlythe same way they do in younger adults or if they cause different side effectsor problems in older people. There is no specific information comparing useof guanabenz in the elderly with use in other age groups. However, dizziness,faintness, or drowsiness may be more likely to occur in the elderly, who areusually more sensitive to the effects of guanabenz.
Other medicines?Although certain medicines should not be usedtogether at all, in other cases two different medicines may be used togethereven if an interaction might occur. In these cases, your doctor may want tochange the dose, or other precautions may be necessary. When you are takingguanabenz, it is especially important that your health care professional knowif you are taking any of the following:
- Beta-blockers (acebutolol [e.g., Sectral], atenolol [e.g., Tenormin],betaxolol [Kerlone], bisoprolol [e.g., Zebeta], carteolol [e.g., Cartrol],labetalol [e.g., Normodyne], metoprolol [e.g., Lopressor], nadolol [e.g.,Corgard], oxprenolol [e.g., Trasicor], penbutolol [e.g., Levatol], pindolol[e.g., Visken], propranolol [e.g., Inderal], sotalol [e.g., Sotacor], timolol[e.g., Blocadren])?Effects on blood pressure may be increased. Also,the risk of unwanted effects when guanabenz treatment is stopped suddenlymay be increased
Other medical problems?The presence of other medicalproblems may affect the use of guanabenz. Make sure you tell your doctor ifyou have any other medical problems, especially:
- Heart or blood vessel disease?Lowering blood pressure may makesome conditions worse
- Kidney disease or
- Liver disease?Effects of guanabenz may be increased becauseof slower removal of guanabenz from the body
Proper Use of This Medicine
In additionto the use of the medicine your doctor has prescribed, treatment for yourhigh blood pressure may include weight control and care in the types of foodsyou eat, especially foods high in sodium. Your doctor will tell you whichof these are most important for you. You should check with your doctor beforechanging your diet.
Many patients who have high blood pressure will not notice any signs ofthe problem. In fact, many may feel normal. It is very important that you take your medicine exactly as directed and thatyou keep your appointments with your doctor even if you feel well.
Remember that this medicine will not cure your high blood pressure butit does help control it. Therefore, you must continue to take it as directedif 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 problemssuch as heart failure, blood vessel disease, stroke, or kidney disease.
To help you remember to take your medicine, try to get into the habit oftaking it at the same time each day.
Dosing?The dose of guanabenz will be different fordifferent patients. Follow your doctor's orders or thedirections on the label. The following information includes only theaverage doses of guanabenz. If your dose is different,do not change it unless your doctor tells you to do so.
The number of tablets that you take depends on the strength of the medicine.
- For oral dosage form (tablets):
- For high blood pressure:
- Adults?At first, 4 milligrams (mg) two times a day. Then, yourdoctor 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 andgo back to your regular dosing schedule. Do not double doses.
- If you miss two or more doses in a row, check with your doctor. Ifyour body suddenly goes without this medicine, some unpleasant effects mayoccur. If you have any questions about this, check with your doctor.
Storage?To store this medicine:
- Keep out of the reach of children.
- Store away from heat and direct light.
- Do not store in the bathroom, near the kitchen sink, or in otherdamp places. Heat or moisture may cause the medicine to break down.
- Do not keep outdated medicine or medicine no longer needed. Be surethat any discarded medicine is out of the reach of children.
Precautions While Using This Medicine
It isimportant that your doctor check your progress at regular visits to make surethat this medicine is working properly.
Check with your doctor before you stop taking guanabenz. Your doctor maywant you to reduce gradually the amount you are taking before stopping completely.
Before having any kind of surgery (including dental surgery) or emergencytreatment, tell the medical doctor or dentist in charge that you are usingthis medicine.
Do not take other medicines unless they have been discussedwith your doctor. This especially includes over-the-counter (nonprescription)medicines for appetite control, asthma, colds, cough, hay fever, or sinusproblems, since they may tend to increase your blood pressure.
Guanabenz will add to 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 medicine for hay fever,other allergies, or colds; sedatives, tranquilizers, or sleeping medicine;prescription pain medicine or narcotics; barbiturates; medicine for seizures;muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above whileyou are using this medicine.
Guanabenz may cause some people to become dizzy, drowsy, or less alertthan they are normally. Make sure you know how you reactto this medicine before you drive, use machines, or do anything else thatcould be dangerous if you are dizzy or are not alert.
Guanabenz may cause dryness of the mouth, nose, and throat. For temporaryrelief of mouth dryness, use sugarless candy or gum, melt bits of ice in yourmouth, or use a saliva substitute. However, if your mouth continues to feeldry for more than 2 weeks, check with your medical doctor or dentist. Continuingdryness of the mouth may increase the chance of dental disease, includingtooth decay, gum disease, and fungus infections.
Side Effects of This Medicine
Along with its needed effects, a medicine may cause some unwanted effects.Although not all of these side effects may occur, if they do occur they mayneed medical attention.
Check with your doctor as soon as possible if any of the following sideeffects occur:
Signs and symptoms of overdose
Dizziness (severe); irritability; nervousness; pinpoint pupils; slow heartbeat; unusual tiredness orweakness
Other side effects may occur that usually do not need medicalattention. These side effects may go away during treatment as your body adjuststo the medicine. However, check with your doctor if any of the following sideeffects continue or are bothersome:
After you have been using this medicine for a while, unpleasanteffects may occur if you stop taking it too suddenly. After you stop takingthis medicine, check with your doctor if any of the following effects occur:
Anxiety or tenseness; chest pain; fast or irregular heartbeat; headache; increased salivation; increase in sweating; nausea or vomiting; nervousness or restlessness; shakingor trembling of hands or fingers; stomach cramps; trouble in sleeping
Other side effects not listed above may also occur in some patients. Ifyou notice any other effects, check with your doctor.
Revised: 08/19/1998
