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Horizant Side Effects

Generic Name: gabapentin enacarbil

Note: This page contains information about the side effects of gabapentin enacarbil. Some of the dosage forms included on this document may not apply to the brand name Horizant.

In Summary

Common side effects of Horizant include: dizziness, drowsiness, and sedation. Other side effects include: irritability. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to gabapentin enacarbil: oral tablet extended release

In addition to its needed effects, some unwanted effects may be caused by gabapentin enacarbil (the active ingredient contained in Horizant). In the event that any of these side effects do occur, they may require medical attention.

Severity: Major

You should check with your doctor immediately if any of these side effects occur when taking gabapentin enacarbil:

More common:
  • Bloating or swelling of the face, arms, hands, lower legs, or feet
  • discouragement
  • feeling sad or empty
  • irritability
  • lack of appetite
  • loss of interest or pleasure
  • rapid weight gain
  • tingling of the hands or feet
  • tiredness
  • trouble concentrating
Incidence not known:
  • Black, tarry stools
  • bloody or cloudy urine
  • changes in behavior
  • chest pain or discomfort
  • chills or fever
  • confusion
  • difficulty with breathing
  • dizziness or lightheadedness
  • fainting
  • fast heartbeat
  • nausea or vomiting
  • painful or difficult urination
  • rapid, shallow breathing
  • rash
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • swelling of the face, feet, or lower legs
  • swollen, painful, or tender lymph glands in the neck, armpit, or groin
  • thoughts of killing oneself
  • unusual bleeding or bruising
  • upper right abdominal or stomach pain
  • yellow eyes and skin

Severity: Minor

Some of the side effects that can occur with gabapentin enacarbil may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common:
  • Lack or loss of strength
  • sleepiness or unusual drowsiness
Less common:
  • Blurred vision
  • decreased interest in sexual intercourse
  • dry mouth
  • excess air or gas in the stomach or intestines
  • inability to have or keep an erection
  • sensation of spinning
  • weight gain

For Healthcare Professionals

Applies to gabapentin enacarbil: compounding powder, oral capsule, oral solution, oral tablet, oral tablet extended release

Cardiovascular

Common (1% to 10%): Peripheral edema, vasodilation, hypertension
Rare (less than 0.1%): Atrial fibrillation, heart failure, myocardial infarction, cerebrovascular accident, ventricular extrasystoles, bradycardia, premature atrial contraction, pericardial rub, heart block, pericardial effusion, pericarditis
Postmarketing reports: Cardiac arrest, chest pain, palpitation, tachycardia[Ref]

Dermatologic

Common (1% to 10%): Abrasion, facial edema, purpura, rash, pruritus, acne
Uncommon (0.1% to 1%): Alopecia, eczema, dry skin, increased sweating, urticaria, hirsutism, seborrhea, cyst, herpes simplex
Rare (less than 0.1%): Stevens-Johnson syndrome, angioedema, erythema multiforme, drug rash (with eosinophilia and systemic symptoms), herpes zoster, skin discolor, skin papules, photosensitive reaction, psoriasis, desquamation, maceration, skin nodules, subcutaneous nodule, melanosis, skin necrosis, local swelling
Frequency not reported: DRESS/multiorgan hypersensitivity[Ref]

Endocrine

Rare (less than 0.1%): Hyperthyroid, hypothyroid, goiter, hypoestrogenism, ovarian failure, epididymitis, cushingoid appearance[Ref]

Gastrointestinal

Common (1% to 10%): Diarrhea, dry mouth or throat, constipation, nausea, vomiting, dyspepsia, dental abnormalities, gingivitis, abdominal pain, flatulence
Uncommon (0.1% to 1%): Glossitis, gum hemorrhage, thirst, stomatitis, increased salivation, gastroenteritis, hemorrhoids, bloody stools, fecal incontinence
Rare (less than 0.1%): Pancreatitis, dysphagia, eructation, pancreatitis, peptic ulcer, colitis, blisters in mouth, tooth discoloration, perl├Ęche, salivary gland enlarged, lip hemorrhage, esophagitis, hiatal hernia, hematemesis, proctitis, irritable bowel syndrome, rectal hemorrhage, esophageal spasm
Frequency not reported: Dehydration[Ref]

General

The most common adverse reactions associated with the use of this drug were dizziness, somnolence, and peripheral edema.[Ref]

Genitourinary

Common (1% to 10%): Incontinence, impotence
Uncommon (0.1% to 1%): Hematuria, dysuria, urinary frequency, cystitis, urinary retention, vaginal hemorrhage, amenorrhea, dysmenorrhea, menorrhagia
Frequency not reported: Breast hypertrophy, gynecomastia, sexual dysfunction (including changes in libido, ejaculation disorders, and anorgasmia)[Ref]

Hematologic

Common (1% to 10%): Leucopenia, purpura
Uncommon (0.1% to 1%): Anemia, lymphadenopathy
Rare (less than 0.1%): Thrombocytopenia, thrombophlebitis, leukocytosis, lymphocytosis, increased bleeding time
Frequency not reported: Blood creatine phosphokinase increased, coagulation defect[Ref]

Hepatic

Rare (less than 0.1%): Hepatitis, jaundice, elevated liver function tests SGOT (AST), SGPT (ALT), and bilirubin, hepatomegaly, hepatotoxicity[Ref]

Hypersensitivity

Very rare (less than 0.01%): Hypersensitivity syndrome, a systemic reaction with a variable presentation that can include fever, rash, hepatitis, lymphadenopathy, eosinophilia, and sometimes other signs and symptoms[Ref]

Metabolic

Common (1% to 10%): Weight gain, hyperglycemia
Postmarketing reports: Hyponatremia[Ref]

Musculoskeletal

Common (1% to 10%): Back pain, arthralgia, myalgia, twitching
Uncommon (0.1% to 1%): Tendonitis, arthritis, joint stiffness, joint swelling
Frequency not reported: Rhabdomyolysis, myoclonus
Postmarketing reports: Elevated creatine kinase, rhabdomyolysis[Ref]

Nervous system

Very common (10% or more): Somnolence (21%), dizziness (17%), ataxia (13%)
Common (1% to 10%): Abnormal gait, incoordination, neuralgia, tremor, dysarthria, hyperkinesia, seizures, dysarthria, paresthesia, hypesthesia, coordination abnormal, increased/decreased/absent reflexes, vertigo
Uncommon (less than 1%): Hypokinesia
Rare (less than 0.1%): Movement disorders (e.g., choreoathetosis, dyskinesia, dystonia), loss of consciousness
Frequency not reported: Withdrawal precipitated seizure/status epilepticus
Postmarketing reports: Movement disorder[Ref]

Ocular

Common (1% to 10%): Amblyopia, conjunctivitis, diplopia, nystagmus
Uncommon (0.1% to 1%): Cataract, dry eyes, eye pain, visual field defect, photophobia, bilateral or unilateral ptosis, eye hemorrhage, hordeolum, eye twitching
Rare (less than 0.1%): Eye itching, abnormal accommodation, eye focusing problem, watery eyes, retinopathy, glaucoma, iritis, corneal disorders, lacrimal dysfunction, degenerative eye changes, blindness, retinal degeneration, miosis, chorioretinitis, strabismus[Ref]

Oncologic

Uncommon (0.1% to 1%): Breast cancer
Rare (less than 0.1%): Non-Hodgkin's lymphoma[Ref]

Other

Very common (10% or more): Fatigue (11%), fever (11%)
Common (1% to 10%): Asthenia, accidental injury, otitis media, tremor, pain
Rare (0.01% to 0.1%): Tinnitus
Very rare (less than 0.01%): Sudden unexplained death in patients with epilepsy
Frequency not reported: Sleepwalking, withdrawal symptoms, hearing loss, earache, tinnitus, inner ear infection, otitis, taste loss, unusual taste, ear fullness, perforated ear drum, sensitivity to noise, eustachian tube dysfunction, otitis externa, odd smell, labyrinthitis[Ref]

Psychiatric

Common (1% to 10%): Abnormal thinking, amnesia, depression, hostility, confusion, emotional liability, anxiety, nervousness, amnesia, insomnia
Uncommon (0.1% to 1%): Mental impairment
Rare (less than 0.1%): Hallucinations
Frequency not reported: Suicidal behavior and ideation, hypomania[Ref]

Renal

Rare (less than 0.1%): Acute renal failure[Ref]

Respiratory

Common (1% to 10%): Pharyngitis, dyspnea, cough, bronchitis, respiratory infection, rhinitis
Rare (less than 0.1%): Pulmonary thrombosis, pulmonary embolism
Frequency not reported: Pseudo-croup, hoarseness[Ref]

References

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

2. Cerner Multum, Inc. "Australian Product Information." O 0

3. "Product Information. Neurontin (gabapentin)." Parke-Davis, Morris Plains, NJ.

4. Sahin S, Comert A, Akin O, Ayalp S, Karsidag S "Cutaneous drug eruptions by current antiepileptics: case reports and alternative treatment options." Clin Neuropharmacol 31 (2008): 93-6

5. Gidal BE, Maly MM, Nemire RE, Haley K "Weight gain and gabapentin therapy." Ann Pharmacother 29 (1995): 1048

6. Lasso-de-la-Vega MC, Zapater P, Such J, Perez-Mateo M, Horga JF "Gabapentin-associated hepatotoxicity." Am J Gastroenterol 96 (2001): 3460-2

7. Ragucci MV, Cohen JM "Gabapentin-induced hypersensitivity syndrome." Clin Neuropharmacol 24 (2001): 103-5

8. Zhang C, Glenn DG, Bell WL, O'donovan CA "Gabapentin-induced Myoclonus in End-stage Renal Disease." Epilepsia 46 (2005): 156-158

9. The US, Gabapentin Study Group No. 5 "Gabapentin as add-on therapy in refractory partial epilepsy: a double-blind, placebo-controlled, parallel-group study." Neurology 43 (1993): 2292-8

10. Pittenger C, Desan PH "Gabapentin abuse, and delirium tremens upon gabapentin withdrawal." J Clin Psychiatry 68 (2007): 483-4

11. Crawford P, Ghadiali E, Lane R, Blumhardt L, Chadwick D "Gabapentin as an antiepileptic drug in man." J Neurol Neurosurg Psychiatry 50 (1987): 682-6

12. Reeves AL, So EL, Sharbrough FW, Krahn LE "Movement disorders associated with the use of gabapentin." Epilepsia 37 (1996): 988-90

13. Tallian KB, Nahata MC, Lo W, Tsao CY "Gabapentin associated with aggressive behavior in pediatric patients with seizures." Epilepsia 37 (1996): 501-2

14. Short C, Cooke L "Hypomania induced by gabapentin." Br J Psychiatry 166 (1995): 679-80

15. Silvia RJ, Spitznas AL "Gabapentin-Related Changes in Renal Function: Two Case Reports." J Clin Psychopharmacol 27 (2007): 118-119

Not all side effects for Horizant may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. Drugs.com does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.

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