Important Safety Information for HORIZANT® (gabapentin enacarbil) Extended-Release Tablets
HORIZANT® (gabapentin enacarbil) Extended-Release Tablets are indicated for the treatment of
moderate-to-severe primary Restless Legs Syndrome (RLS) in adults. HORIZANT is not recommended for
patients who are required to sleep during the daytime and remain awake at night.
HORIZANT® (gabapentin enacarbil) Extended-Release Tablets are indicated for the management of
postherpetic neuralgia (PHN) in adults.
IMPORTANT SAFETY INFORMATION
WARNINGS AND PRECAUTIONS
Effects on Driving
HORIZANT may cause significant driving impairment. The duration of driving impairment after starting
therapy is unknown. Patients should not drive until they have enough experience on HORIZANT to know
if it impairs their driving. Patients’ ability to assess their driving competence and degree of
caused by HORIZANT can be imperfect.
Somnolence/Sedation and Dizziness
HORIZANT causes somnolence/sedation and dizziness. Patients should not drive or operate other
complex machinery until they have enough experience on HORIZANT to know if it impairs their ability to
perform these tasks.
Lack of Interchangeability with Gabapentin
HORIZANT is not interchangeable with other gabapentin products because of differing pharmacokinetic
profiles. The same dose of HORIZANT results in different plasma concentrations of gabapentin relative
to other gabapentin products. The safety and effectiveness of HORIZANT in patients with epilepsy have
not been studied.
Suicidal Behavior and Ideation
HORIZANT is a prodrug of gabapentin, an antiepileptic drug (AED). AEDs increase the risk of suicidal
thoughts or behavior in patients taking these drugs for any indication. As a prodrug of gabapentin,
HORIZANT also increases this risk. Patients treated with any AED for any indication should be monitored
for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual
changes in mood or behavior. Anyone considering prescribing HORIZANT must balance the risk of
suicidal thoughts or behavior with the risk of untreated illness.
Patients, caregivers, and families should be informed that HORIZANT increases the risk of suicidal
thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of
the signs and symptoms of depression, any unusual changes in mood or behavior, or the emergence of
suicidal thoughts, behavior, or thoughts of self-harm. Behaviors of concern should be reported
immediately to healthcare providers.
There is evidence from case reports, human studies, and animal studies associating gabapentin
with serious, life-threatening, or fatal respiratory depression when co-administered with central
nervous system (CNS) depressants, including opioids, or in the setting of underlying respiratory
impairment. When the decision is made to co-prescribe HORIZANT with another CNS
depressant, particularly an opioid, or to prescribe HORIZANT to patients with underlying
respiratory impairment, monitor patients for symptoms of respiratory depression and sedation,
and consider initiating HORIZANT at a low dose. The management of respiratory depression
may include close observation, supportive measures, and reduction or withdrawal of CNS
depressants (including HORIZANT).
Drug Reaction With Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan Hypersensitivity
Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), also known as multiorgan
hypersensitivity, has been reported in patients taking antiepileptic drugs, including gabapentin.
HORIZANT is a prodrug of gabapentin. Some of these events have been fatal or life-threatening. DRESS
typically, although not exclusively, presents with fever, rash, and/or lymphadenopathy, in association
with other organ system involvement, such as hepatitis, nephritis, hematological abnormalities,
myocarditis, or myositis sometimes resembling an acute viral infection. Eosinophilia is often present.
Because this disorder is variable in its expression, other organ systems not noted here may be involved.
It is important to note that early manifestations of hypersensitivity, such as fever or lymphadenopathy,
may be present even though rash is not evident. If such signs or symptoms are present, the patient
should be evaluated immediately. HORIZANT should be discontinued if an alternative etiology for the
signs or symptoms cannot be established.
Discontinuation of HORIZANT
When discontinuing HORIZANT, patients with RLS receiving 600 mg or less once daily can discontinue
the drug without tapering. If the recommended dose is exceeded, the dose should be reduced to
600 mg daily for 1 week prior to discontinuation to minimize the potential of withdrawal seizure.
In patients with PHN receiving HORIZANT twice daily, the dose should be reduced to once daily for 1
week prior to discontinuation to minimize the potential of withdrawal seizure.
In an oral carcinogenicity study, gabapentin enacarbil increased the incidence of pancreatic acinar cell
adenoma and carcinoma in male and female rats. The clinical significance of this finding is unknown.
The most common adverse reactions for patients with RLS (incidence >10% and at least 2 times the rate
of placebo) were somnolence/sedation and dizziness.
The most common adverse reactions for patients with PHN (incidence >10% and greater than placebo)
were dizziness, somnolence, and headache.
Gabapentin enacarbil is released faster from HORIZANT Extended-Release tablets in the presence of
alcohol. Consumption of alcohol is not recommended when taking HORIZANT.
HORIZANT taken in conjunction with morphine causes increased somnolence/sedation, dizziness, and
USE IN SPECIAL POPULATIONS
Pregnancy and Lactation
There are no adequate data on the developmental risk associated with the use of HORIZANT in pregnant
women. In nonclinical studies in rats and rabbits, administration of gabapentin enacarbil was
developmentally toxic when administered to pregnant animals at doses and gabapentin exposures
greater than those used clinically.
It is not known whether gabapentin derived from HORIZANT is secreted in human milk; however,
gabapentin is secreted into human milk following oral administration of other gabapentin products.
There are no data on the effects of gabapentin on the breastfed infant or the effects on milk
The developmental and health benefits of breastfeeding should be considered along with the mother’s
clinical need for HORIZANT and any potential adverse effects on the breastfed infant from HORIZANT or
from the underlying maternal condition.
Safety and effectiveness of HORIZANT in pediatric patients have not been studied.
Clinical trials of HORIZANT for the treatment of RLS did not include a sufficient number of patients 65
years and older to determine whether they respond differently from younger individuals. Because
elderly patients are more likely to have decreased renal function, the frequency of dosing may need to
be adjusted based on calculated creatinine clearance in these patients.
Gabapentin is known to be almost exclusively excreted by the kidney, and the risk of adverse reactions
to this drug may be greater in patients with impaired renal function. The dose of Horizant should be
adjusted in patients with renal impairment based upon creatinine clearance. HORIZANT is not
recommended for treatment of RLS in patients receiving hemodialysis.
For additional safety information, please see the complete Prescribing
To report SUSPECTED ADVERSE REACTIONS, contact Azurity Pharmaceuticals, Inc. at 1-800-461-7449,
or FDA at 1-800-FDA-1088 or www.fda.gov/MedWatch.