Guanfacine hydrochloride

What is Guanfacine hydrochloride?

Guanfacine is given alone or in combination with other drugs, especially thiazide diuretics, for the treatment of high blood pressure.

What is the most important information I should know about Guanfacine hydrochloride?

You must take guanfacine regularly for it to be effective. Since blood pressure declines gradually, it may be several weeks before you get the full benefit of guanfacine. You must continue taking it even if you are feeling well. Guanfacine does not cure high blood pressure; it only keeps it under control.

Do not abruptly stop taking guanfacine. It may cause rebound or "overshoot" hypertension (sudden increase in blood pressure) and also cause nervousness and anxiety. This is very dangerous and could result in a medical emergency.

Who should not take Guanfacine hydrochloride?

Do not take guanfacine if you are allergic or sensitive to the drug.

What should I tell my doctor before I take the first dose of Guanfacine hydrochloride?

Tell your doctor about all prescription, over-the-counter, and herbal medications you are taking before beginning treatment with guanfacine. Also, talk to your doctor about your complete medical history, especially if you have atherosclerosis (hardening and narrowing of the arteries); heart disease; kidney or liver disease; or have suffered a recent heart attack or stroke.

What is the usual dosage?

The information below is based on the dosage guidelines your doctor uses. Depending on your condition and medical history, your doctor may prescribe a different regimen. Do not change the dosage or stop taking your medication without your doctor's approval.

Adults: The recommended initial dose of guanfacine when given alone or in combination with another drug is 1 milligram (mg) taken daily at bedtime. If after 3-4 weeks of therapy, 1 mg does not give a satisfactory result, a dose of 2 mg may be given. Higher daily doses have been used, but side effects increase significantly with doses of 3 mg/day.

The safety and effectiveness of guanfacine have not been established in children <12 years of age.

How should I take Guanfacine hydrochloride?

Take guanfacine exactly as prescribed by your doctor. Guanfacine should be taken at bedtime, since it will probably cause drowsiness.

In some cases, you may take 2 evenly spaced doses per day rather than a single dose at bedtime.

What should I avoid while taking Guanfacine hydrochloride?

Since guanfacine causes drowsiness and may also make you dizzy, do not drive, climb, or perform hazardous tasks until you find out exactly how guanfacine affects you.

While taking guanfacine, drink alcoholic beverages with care. You may feel intoxicated after drinking only a small amount of alcohol.

If you have been taking guanfacine for a while, do not stop taking it without speaking to your doctor. Stopping abruptly may result in nervousness, rapid pulse, anxiety, heartbeat irregularities, and so-called rebound high blood pressure (higher than before you started taking guanfacine). If you do have rebound high blood pressure, it will probably develop 2-4 days after your last dose of guanfacine. Rebound high blood pressure, if it occurs, will usually decrease and then disappear over a period of 2-4 days.

What are possible food and drug interactions associated with Guanfacine hydrochloride?

If guanfacine is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining guanfacine with the following: barbiturates (eg, amobarbital, secobarbital, phenobarbital), benzodiazepines (eg, alprazolam or diazepam), phenothiazines (eg, chlorpromazine or thioridazine), phenytoin

What are the possible side effects of Guanfacine hydrochloride?

Side effects cannot be anticipated. If any develop or change in intensity, tell your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking this drug.

Side effects may include: constipation, dizziness, dry mouth, feeling tired, headache, impotence, sleepiness, weakness, insomnia, fainting, involuntary leakage of urine (urinary incontinence), pink eye (conjunctivitis), tingling or numbness, depression, skin reactions/rash

Can I receive Guanfacine hydrochloride if I am pregnant or breastfeeding?

The effects of guanfacine during pregnancy and breastfeeding are unknown. Tell your doctor immediately if you are pregnant, plan to become pregnant, or are breastfeeding. Use caution when taking guanfacine while breastfeeding.

What should I do if I miss a dose of Guanfacine hydrochloride?

Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and go back to your regular schedule. Never take 2 doses at once. If you miss taking guanfacine for 2 or more days in a row, check with your doctor.

How should I store Guanfacine hydrochloride?

Store at room temperature in a tight, light-resistant container.