guanfacine (Intuniv, Tenex) (cont.)

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STORAGE: Tablets should be stored at room temperature, between 15 C to 30 C (59 F to 86 F).

PRESCRIBED FOR: Extended release guanfacine (Intuniv) is used alone or in combination with other medications for the treatment of ADHD. Immediate release guanfacine (Tenex) is used alone or in combination with other medications for the treatment of high blood pressure.

DOSING:

  • Extended release guanfacine for the treatment of ADHD: The recommended dose is 1 to 4 mg by mouth in the morning or evening. Patients are usually started on 1 mg once daily which is then increased in increments no larger than 1 mg/week as needed or tolerated. Tablets should not be administered with high-fat meals.
  • Immediate release guanfacine for the treatment of hypertension: The recommended dose is 1 mg usually at bedtime. The dose may be increased at 3 to 4 week intervals as necessary. The usual dose range is 0.5 to 2 mg once daily.

DRUG INTERACTIONS: Rifampin and St. John's wort may reduce blood levels of guanfacine by increasing its metabolism (breakdown) in the intestine; doses of guanfacine may need to be increased when combined with drugs that reduce its blood levels.

Other drugs that also may reduce blood levels of guanfacine include carbamazepine (Tegretol, Tegretol XR , Equetro, Carbatrol, Epitol, Teril), phenytoin (Dilantin, Dilantin-125), phenobarbital, oxcarbazepine (Trileptal), rifabutin, rifampin, rifapentine, bosentan (Tracleer), and tipranavir/ritonavir (Aptivus).

Ketoconazole (Nizoral, Extina, Xolegel, Kuric), itraconazole (Sporanox), and simeprevir (Olysio) may increase blood levels of guanfacine by decreasing its metabolism in the intestine; the dose of guanfacine may need to be decreased when combined with drugs that increase its blood levels.

PREGNANCY: Guanfacine has not been adequately evaluated in pregnant women. Due to the lack of safety data, guanfacine should be used cautiously during pregnancy, taking into account the potential benefits and risks of therapy. Guanfacine is classified as FDA pregnancy risk B.

Medically Reviewed by a Doctor on 4/16/2014


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