GUANABENZ

Brand & Generic Names

Wytensin

Basic Information

• Habit forming? No
• Prescription needed? Yes
• Available as generic? No
• Drug class: Antihypertensive

Uses

Controls, but doesn't cure, high blood pressure.

Dosage & Usage Information

How to take:
Tablet--Swallow with liquid or food to lessen stomach irritation. If you can't swallow whole, crumble tablet and take with liquid or food.

When to take:
At the same times each day.

If you forget a dose:
Take as soon as you remember up to 2 hours late. If more than 2 hours, wait for next scheduled dose (don't double this dose).

What drug does:
Relaxes muscle cells of small arteries.
Slows heartbeat.

Time lapse before drug works:
1 hour.

Don't take with:
Any other medicine without consulting your doctor or pharmacist.

Overdose

SYMPTOMS:
Severe dizziness, slow heartbeat, unusual tiredness or weakness, pinpoint pupils, fainting, coma.

WHAT TO DO:

• Dial 911 (emergency) or O (operator) for an ambulance or medical help. Then give first aid immediately.
• If patient is unconscious and not breathing, give mouth-to- mouth breathing. If there is no heartbeat, use cardiac massage and mouth-to-mouth breathing (CPR). Don't try to make patient vomit. If you can't get help quickly, take patient to nearest emergency facility.
• See EMERGENCY Information.

Possible Adverse Reactions or Side Effects

Life-threatening:

In case of overdose, see Overdose section.

Common:

• Dry mouth, drowsiness.
• Insomnia, weakness.

Infrequent:

• Irregular heartbeat, shakiness in hands.
• Dizziness, appetite loss, nausea, vomiting, painful or difficult urination, headache.

Rare:

Decreased sex drive.

Warnings & Precautions

Don't take if:
You are allergic to any sympathomimetic drug.

Before you start, consult your doctor:

• If you have blood disease.
• If you have heart disease.
• If you have liver disease.
• If you have diabetes or overactive thyroid.
• If you will have surgery within 2 months, including dental surgery, requiring general or spinal anesthesia.

Over age 60:
Adverse reactions and side effects may be more frequent and severe than in younger persons. Hot weather may cause need to reduce dosage.

Pregnancy:
Risk to unborn child outweighs drug benefits. Don't use.

Breast-feeding:
Unknown effect. Consult doctor.

Infants & children:
Not recommended.

Prolonged use:
Side effects tend to diminish. Request uric-acid and kidney- function studies periodically.

Skin & sunlight:
No problems expected.

Driving, piloting or hazardous work:
Avoid if you feel dizzy; otherwise, no problems expected.

Discontinuing:
Don't discontinue without consulting doctor. Dose may require gradual reduction if you have taken drug for a long time. Doses of other drugs may also require adjustment. Abruptly discontinuing may cause anxiety, chest pain, salivation, headache, abdominal cramps, fast heartbeat, increased sweating, tremors, insomnia.

Others:

• Stay away from high-sodium foods. Lose weight if you are overweight.
• May interfere with the accuracy of some medical tests.

Possible Interaction with Other Drugs

GENERIC NAME	COMBINED EFFECT
------------------------	-----------------------
ACE inhibitors*:	Possible excessive
captopril, enalapril,	potassium in blood.
Antihypertensives,	Decreases blood
other*	pressure more than either alone.
	May be beneficial, but requires
	dosage adjustment.
Beta-blockers*	Blood pressure control more
	difficult.
Central nervous system	Increased brain depression. Avoid.
Clozapine	Toxic effect on the central nervous
	system.
Diuretics*	Decreases blood pressure more than
	either alone. May be beneficial,
	but requires dosage adjustment.
Ethinamate	Dangerous increased effects of
	ethinamate. Avoid combining.
Fluoxetine	Increased depressant effects of
	both drugs.
Guanfacine	May increase depressant effects of
	either drug.
Leucovorin	High alcohol content of leucovorin
	may cause adverse effects.
Methyprylon	Increased sedative effect, perhaps
	to dangerous level. Avoid.
Nabilone	Greater depression of central
	nervous system.
Nicardipine	Blood pressure drop. Dosages may
	require adjustment.
Nimodipine	Dangerous blood pressure drop.
Sertraline	Increased depressive effects of
	both drugs.

Possible Interaction with Other Substances

INTERACTS WITH	COMBINED EFFECT
---------------	---------------
Alcohol:	Oversedation. Avoid.
Caffeine.	Overstimulation. Avoid.
Cocaine:	Overstimulation. Avoid.
Salt.	Decrease salt intake to increase
	beneficial effects of guanabenz.
Marijuana:	Overstimulation. Avoid.
Tobacco:	Decreased guanabenz effect.