Creatinine Clearance
(mL/min)  Titration  Maintenance  Tapering
 ≥60  600 mg in AM for 3 days  600 mg twice daily  600 mg in AM for
1 week
 30 – 59  300 mg in AM for 3 days  300 mg twice daily.
Increase to 600 mg
twice daily as
neededa  Reduce current
maintenance dose to
once daily in AM for
1 week
 15 – 29  300 mg in AM on Day 1
and Day 3  300 mg in AM.
Increase to 300 mg
twice daily if
neededa  If taking 300 mg
twice daily, reduce to
300 mg once daily in
AM for 1 week.
If taking 300 mg once
daily, no taper
needed.
 <15  None  300 mg every other
day in AM.
Increase to 300 mg
once daily in AM if
neededa  None
 <15 on hemodialysis  None    300 mg following
   every dialysis.
   Increase to 600 mg
   following every
   dialysis if neededa  None
In patients with stable renal function, CrCl can be estimated using the equation of Cockcroft and Gault:
         for males: CrCl = (140-age)(weight)/[(72)(SCr)]
         for females: CrCl = (0.85)(140-age)(weight)/[(72)(SCr)]
where age is in years, weight is in kilograms, and SCr is serum creatinine in mg/dL.
3 DOSAGE FORMS AND STRENGTHS
HORIZANT Extended-Release Tablets, 300 mg, are white to off-white, oval-shaped tablets debossed with “GS TF7” and 600 mg, are white to off-white, oval-shaped tablets debossed with “GS LFG”. Both the 300 mg and 600 mg tablets may contain occasional black/grey spots.
4 CONTRAINDICATIONS
None.
5 WARNINGS AND PRECAUTIONS
5.1 Effects on DrivingHORIZANT may cause significant driving impairment [see Clinical Studies (14.3)]. The duration of driving impairment after starting therapy with HORIZANT is unknown. Patients taking HORIZANT should not drive until they have gained sufficient experience to assess whether HORIZANT impairs their ability to drive. However, prescribers and patients should be aware that patients’ ability to assess their own driving competence, as well as their ability to assess the degree of somnolence caused by HORIZANT, can be imperfect. Whether the impairment is related to somnolence [see Warnings and Precautions (5.2)] or other effects of HORIZANT is unknown.
5.2 Somnolence/Sedation and DizzinessHORIZANT causes somnolence/sedation and dizziness (see Tables 4 and 5). Patients should be advised not to drive a car or operate other complex machinery until they have gained sufficient experience on HORIZANT to assess whether HORIZANT impairs their ability to perform these tasks.
During the controlled trials in patients with RLS, somnolence/sedation was reported in 20% of patients treated with 600 mg of HORIZANT per day compared with 6% of patients receiving placebo. In those patients treated with HORIZANT who reported somnolence, the somnolence persisted during treatment in about 30%. In the remaining patients, symptoms resolved within 3 to 4 weeks. Dizziness was reported in 13% of