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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.

In Summary

Common side effects of Tenex include: asthenia, constipation, drowsiness, dizziness, fatigue, and xerostomia. Other side effects include: impotence. See below for a comprehensive list of adverse effects.

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
  • confusion
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • sweating
  • unusual tiredness or weakness
Less common
  • Chest pain or discomfort
  • cough
  • difficulty with breathing
  • fast, slow, pounding, or irregular heartbeat
  • increased need to urinate
  • lightheadedness, dizziness, or fainting
  • mental depression
  • noisy breathing
  • passing urine more often
  • tightness in the chest
Incidence not known
  • Agitation
  • back pain
  • cracks in the skin
  • drowsiness
  • fast, pounding, or irregular pulse
  • feeling of constant movement of self or surroundings
  • fever
  • headache
  • irritability
  • loss of consciousness
  • loss of heat from the body
  • mood or mental changes
  • numbness or tingling in the arms, legs, or face
  • red, swollen skin
  • scaly skin
  • seeing or hearing things that are not there
  • seizures
  • sensation of spinning
  • stiff neck
  • swelling
  • vomiting
  • weakness

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
  • Constipation
  • dizziness
  • dryness of the mouth
  • nausea
  • sleepiness or unusual drowsiness
  • unusual dullness or feeling of sluggishness
  • upper abdominal or stomach pain
  • weight gain
Less common
  • Belching
  • decreased appetite
  • decreased sexual ability
  • dry, itching, or burning eyes
  • heartburn
  • indigestion
  • lack or loss of strength
  • paleness of the skin
  • stomach discomfort, upset, or pain
  • trouble with sleeping
Incidence not known
  • Change in taste
  • decreased interest in sexual intercourse
  • difficulty in moving
  • general feeling of discomfort or illness
  • hair loss, thinning of hair
  • inability to have or keep an erection
  • joint pain or swelling
  • leg cramp or pain
  • loss in sexual ability, desire, drive, or performance
  • muscle ache, cramp, pain, or stiffness
  • seeing or hearing things that are not there

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
  • sweating

For Healthcare Professionals

Applies to guanfacine: oral tablet, oral tablet extended release

General

The most common adverse reactions were dry mouth, somnolence, headache, fatigue, dizziness, abdominal pain, constipation, appetite decreased, and sedation.[Ref]

Gastrointestinal

Very common (10% or more): Dry mouth (up to 54%), abdominal pain (up to 15%), constipation (up to 15%)
Common (1% to 10%): Vomiting, diarrhea, nausea, abdominal/stomach discomfort
Uncommon (0.1% to 1%): Dyspepsia[Ref]

Nervous system

Very common (10% or more): Somnolence (up to 40.6%), headache (up to 28%), dizziness (up to 16%), sedation (10.2%)
Common (1% to 10%): Lethargy, convulsion, dizziness postural, syncope
Rare (less than 0.1%): Hypersomnia
Postmarketing reports: Tremor, paresthesias, vertigo, taste alteration, hypertensive encephalopathy[Ref]

Other

Very common (10% or more): Fatigue (up to 22%)
Common (1% to 10%): Asthenia
Uncommon (0.1% to 1%): Chest pain
Rare (less than 0.1%): Malaise[Ref]

Metabolic

Very common (10% or more): Appetite decreased (up to 15%)
Common (1% to 10%): Weight increased
Frequency not reported: Body mass index increased
Postmarketing reports: Edema

Psychiatric

Common (1% to 10%): Insomnia, depression, anxiety, affect lability, middle insomnia, nightmare, irritability
Uncommon (0.1% to 1%): Agitation, hallucination
Postmarketing reports: Confusion[Ref]

Cardiovascular

Common (1% to 10%): Hypotension, bradycardia, orthostatic hypotension, tachycardia
Uncommon (0.1% to 1%): Pallor, atrioventricular block first degree, sinus arrhythmia, blood pressure increased, heart rate decreased
Rare (less than 0.1%): Hypertension
Frequency not reported: QTc prolongation
Postmarketing reports: Palpitations, rebound hypertension

Genitourinary

Common (1% to 10%): Impotence, enuresis
Uncommon (0.1% to 1%): Pollakiuria
Frequency not reported: Urinary frequency increased
Postmarketing reports: Erectile dysfunction[Ref]

Dermatologic

Common (1% to 10%): Rash, pruritus
Postmarketing reports: Alopecia, dermatitis, exfoliative dermatitis

Respiratory

Uncommon (0.1% to 1%): Asthma
Postmarketing reports: Dyspnea

Hepatic

Uncommon (0.1% to 1%): ALT increased

Immunologic

Uncommon (0.1% to 1%): Hypersensitivity

Musculoskeletal

Postmarketing reports: Arthralgia, leg cramps, leg pain, myalgia

Ocular

Postmarketing reports: Blurred vision

References

1. "Product Information. Intuniv (guanfacine)." Shire US Inc, Florence, KY.

2. "Product Information. Tenex (guanfacine)." Wyeth-Ayerst Laboratories, Philadelphia, PA.

3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

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