Guanfacine Hydrochloride (Page 3 of 3)
Postmarketing Experience
An open-label postmarketing study involving 21,718 patients was conducted to assess the safety of guanfacine hydrochloride 1 mg/day given at bedtime for 28 days. Guanfacine hydrochloride was administered with or without other antihypertensive agents. Adverse events reported in the postmarketing study at an incidence greater than 1% included dry mouth, dizziness, somnolence, fatigue, headache and nausea. The most commonly reported adverse events in this study were the same as those observed in controlled clinical trials.
Less frequent, possibly guanfacine hydrochloride-related events observed in the postmarketing study and/or reported spontaneously include:
BODY AS A WHOLE — asthenia, chest pain, edema, malaise, tremor
CARDIOVASCULAR — bradycardia, palpitations, syncope, tachycardia
CENTRAL NERVOUS SYSTEM — paresthesias, vertigo
EYE DISORDERS — blurred vision
GASTROINTESTINAL SYSTEM — abdominal pain, constipation, diarrhea, dyspepsia
LIVER AND BILLIARY SYSTEM — abnormal liver function tests
MUSCULOSKELETAL SYSTEM — arthralgia, leg cramps, leg pain, myalgia
PSYCHIATRIC — agitation, anxiety, confusion, depression, insomnia, nervousness
RREPRODUCTIVE SYSTEM, Male — impotence
RESPIRATORY SYSTEM — dyspnea
SKIN AND APPENDAGES — alopecia, dermatitis, exfoliative dermatitis, pruritus, rash
SPECIAL SENSES — alterations in taste
URINARY SYSTEM — nocturia, urinary frequency
Rare, serious disorders with no definitive cause and effect relationship to guanfacine hydrochloride have been reported spontaneously and/or in the postmarketing study. These events include acute renal failure, cardiac fibrillation, cerebrovascular accident, congestive heart failure, heart block, and myocardial infarction.
DRUG ABUSE AND DEPENDENCE
No reported abuse or dependence has been associated with the administration of guanfacine hydrochloride.
OVERDOSAGE
Signs and Symptoms
Drowsiness, lethargy, bradycardia and hypotension have been observed following overdose with guanfacine.
A 25-year-old female intentionally ingested 60 mg. She presented with severe drowsiness and bradycardia of 45 beats/minute. Gastric lavage was performed and an infusion of isoproterenol (0.8 mg in 12 hours) was administered. She recovered quickly and without sequelae.
A 28-year-old female who ingested 30 — 40 mg developed only lethargy, was treated with activated charcoal and a cathartic, was monitored for 24 hours, and was discharged in good health.
A 2-year-old male weighing 12 kg who ingested up to 4 mg of guanfacine developed lethargy. Gastric lavage (followed by activated charcoal and sorbitol slurry via NG tube) removed some tablet fragments within 2 hours after ingestion, and vital signs were normal.
During 24-hour observation in ICU, systolic pressure was 58 and heart rate 70 at 16 hours post-ingestion. No intervention was required, and child was discharged fully recovered the next day.
Treatment of Overdosage
Gastric lavage and supportive therapy as appropriate. Guanfacine is not dialyzable in clinically significant amounts (2.4%).
DOSAGE AND ADMINISTRATION
The recommended initial dose of guanfacine tablets when given alone or in combination with another antihypertensive drug is 1 mg daily given at bedtime to minimize somnolence. If after 3 to 4 weeks of therapy 1 mg does not give a satisfactory result, a dose of 2 mg may be given, although most of the effect of guanfacine tablets are seen at 1 mg (see CLINICAL PHARMACOLOGY). Higher daily doses have been used, but adverse reactions increase significantly with doses above 3 mg/day.
The frequency of rebound hypertension is low, but it can occur. When rebound occurs, it does so after 2 to 4 days, which is delayed compared with clonidine hydrochloride. This is consistent with the longer half-life of guanfacine. In most cases, after abrupt withdrawal of guanfacine, blood pressure returns to pretreatment levels slowly (within 2 to 4 days) without ill effects.
HOW SUPPLIED
Guanfacine tablets, USP are available in the following dosing strengths (expressed in equivalent amounts of guanfacine):
1 mg – White to off white, round, flat-faced, beveled-edge, uncoated tablets debossed with “U” on one side and “45” on the other side.
Bottles of 100: 29300-458-01
2 mg – Light blue, mottled, round, flat-faced, beveled-edge, uncoated tablets debossed with “U” on one side and “46” on the other side.
Bottles of 100: 29300-459-01
Store at controlled temperature, between 20° and 25°C (68°F and 77°F). [see USP Controlled Room Temperature].
Dispense in a tight, light-resistant container.
Please address medical inquiries to Unichem’s toll free # 1-866-562-4616.
Manufactured by:
UNICHEM LABORATORIES LTD.
Ind. Area, Meerut Road, Ghaziabad – 201 003, India
Manufactured for:
01-R-07/2020
13012677
PACKAGE LABEL.PRINCIPAL DISPLAY PANEL
GUANFACINE HYDROCHLORIDE guanfacine hydrochloride tablet | ||||||||||||||||||
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GUANFACINE HYDROCHLORIDE guanfacine hydrochloride tablet | ||||||||||||||||||
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Labeler — Unichem Pharmaceuticals (USA), Inc. (181620514) |
Revised: 03/2021 Unichem Pharmaceuticals (USA), Inc.
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