Tenex Side Effects
Generic name: guanfacine
Note: This document contains side effect information about guanfacine. Some of the dosage forms listed on this page may not apply to the brand name Tenex.
Some side effects of Tenex may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.
For the Consumer
Applies to guanfacine: oral tablet, oral tablet extended release
Along with its needed effects, guanfacine (the active ingredient contained in Tenex) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur while taking guanfacine:More common
- Blurred vision
- dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
- unusual tiredness or weakness
- Chest pain or discomfort
- difficulty with breathing
- fast, slow, or irregular heartbeat
- increased need to urinate
- lightheadedness, dizziness, or fainting
- mental depression
- noisy breathing
- passing urine more often
- pounding heartbeat
- tightness in the chest
Get emergency help immediately if any of the following symptoms of overdose occur while taking guanfacine:Symptoms of overdose
- Dizziness (extreme) or faintness
- unusual tiredness or weakness (severe)
Some side effects of guanfacine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:More common
- dryness of the mouth
- sleepiness or unusual drowsiness
- unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness
- upper abdominal or stomach pain
- weight gain
- Acid or sour stomach
- decreased appetite
- decreased sexual ability
- dry, itching, or burning eyes
- lack or loss of strength
- paleness of the skin
- stomach discomfort, upset, or pain
- trouble with sleeping
After you stop using this medicine, it may still produce some side effects that need attention. During this period of time, check with your doctor immediately if you notice the following side effects:
- Anxiety or tenseness
- increased salivation
- nervousness or restlessness
- shaking or trembling of the hands and fingers
- stomach cramps
For Healthcare Professionals
Applies to guanfacine: oral tablet, oral tablet extended release
Guanfacine (the active ingredient contained in Tenex) is generally well-tolerated. In a study of 580 hypertensive patients, only 7% withdrew due to adverse side effects. In addition, most side effects were mild, dose-related, and resolved over time.
Nervous system side effects have included fatigue or a sedative effect and dizziness in 33% and 15% of patients, respectively. After one year of therapy, the incidence of these side effects falls to 6% and 1%, respectively. Headaches occur in less than 5% of patients. Nervous system side effects associated with the extended-release formulation have included somnolence (38%), fatigue (14%), headache (24%), lethargy (6%), dizziness (6%), and postural dizziness (less than 2%).
Gastrointestinal side effects have included dry mouth in up to 60% of patients. Constipation has been associated with the use of this drug in 14% of patients. After one year of therapy the incidence of dry mouth and constipation averages 15% and 3%, respectively. Gastrointestinal side effects associated with the extended-release formulation have included dry mouth (4%), upper abdominal pain (10%), nausea (6%), and dyspepsia (less than 2%).
Cardiovascular side effects have included orthostatic hypotension and palpitations, each of which is rare. There is limited, indirect (ECG) evidence of left ventricular hypertrophy resolution after guanfacine (the active ingredient contained in Tenex) therapy. Cardiovascular side effects associated with the extended-release formulation have included hypotension/decreased blood pressure (6%), atrioventricular block (less than 2%), bradycardia (less than 2%), and sinus arrhythmia (less than 2%) .
Genitourinary complaints in male patients are limited to impotence, which is associated with higher doses (daily doses of 3 mg or more).
Metabolic side effects associated with the extended-release formulation have included decreased appetite (5%), and constipation (3%).
Psychiatric side effects associated with the extended-release formulation have included irritability (6%)
Postmarketing reports: Hallucinations have been reported in pediatric patients receiving guanfacine (the active ingredient contained in Tenex) for treatment of attention-deficit hyperactivity disorder.
Respiratory side effects associated with the extended-release formulation have included asthma (less than 2%).
More Tenex resources
- Tenex Prescribing Information (FDA)
- Tenex Advanced Consumer (Micromedex) - Includes Dosage Information
- Tenex Monograph (AHFS DI)
- Tenex MedFacts Consumer Leaflet (Wolters Kluwer)
- Guanfacine Prescribing Information (FDA)
- Guanfacine Professional Patient Advice (Wolters Kluwer)
- Intuniv extended-release tablets MedFacts Consumer Leaflet (Wolters Kluwer)
- Intuniv Prescribing Information (FDA)
- Intuniv Consumer Overview
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