Guanethidine (By mouth)
gwahn-ETH-i-deen
Treats high blood pressure.
Drug classes
Antihypertensive (About this – PubMed Health)
Uses
Uses of This Medicine
Guanethidine belongs to the general class of medicines called antihypertensives. It is used to treat high blood pressure (hypertension).
High blood pressure adds to the work load of the heart and arteries. If it 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, resulting in a stroke, heart failure, or kidney failure. High blood pressure may also increase the risk of heart attacks. These problems may be less likely to occur if blood pressure is controlled.
Guanethidine works by controlling nerve impulses along certain nerve pathways. As a result, it relaxes the blood vessels so that blood passes through them more easily. This helps to lower blood pressure.
Guanethidine is available only with your doctor’s prescription.
Other uses (PubMed Health)
How To Use
Tablet
Your doctor will tell you how much medicine to use and how often.
Keep using the medicine for as long as your doctor orders. Your blood pressure can still be high even if you feel fine.
If a dose is missed:
Skip the missed dose and then use your next dose at your usual time.
You should not use two doses at the same time.
How to Store and Dispose of This Medicine:
Store the tablets at room temperature, away from heat, moisture, and direct light.
Keep all medicine out of the reach of children.
Drugs and Foods to Avoid
Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.
Avoid drinking alcohol while using guanethidine.
Tell your doctor if you are using digoxin (Lanoxin®), diet pills, decongestants (such as pseudoephedrine or phenylpropanolamine), ephedrine, Ritalin®, diuretics (water pills), birth control pills, or medicines to treat depression (such as amitriptyline or imipramine), mental problems (such as chlorpromazine), or nausea (such as Compazine®).
When Not To Use
You should not use this medicine if you have had an allergic reaction to guanethidine, if you have congestive heart failure, pheochromocytoma (a tumor on the adrenal gland), or if you use monoamine oxidase (MAO) inhibitors such as Parnate®, Marplan®, Nardil®, or Eldepryl®.
Warnings
If you are pregnant or breastfeeding, talk to your doctor before using this medicine.
Talk with your doctor before using guanethidine if you have asthma, a stomach ulcer, kidney disease, or have had a heart attack.
Tell your doctor or dentist that you are using guanethidine before having any surgery.
This medicine may make you dizzy or drowsy, especially when you first start using it. Avoid driving or using machinery until you know how the medicine will affect you.
Dizziness may be worse when you stand up quickly after you have been sitting or lying down. Getting up slowly from a sitting or lying position may help decrease dizziness. If you start to feel faint or dizzy, sit or lie down.
Dizziness may be a problem in the morning when you first get up, in hot weather, if you exercise, or if you drink alcohol. Avoid standing or exercising for long periods.
Tell your doctor if you get a fever. Your doctor may need to change your dose of the medicine while you have the fever.
Possible side effects
Summary More details
Call your doctor right away if you notice any of these side effects:
Trouble breathing, feeling short of breath
Severe diarrhea
Fainting
If you notice these less serious side effects, talk with your doctor:
Dizziness
Blurred vision
Swelling of hands, legs, or feet.
Trouble releasing semen during sex
If you notice other side effects that you think are caused by this medicine, tell your doctor.
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
More side effects of this drug
Brand names include
Ismelin
There may be other brand names for this medicine.