Gabapentin for RLS
Clinical bottom line
On the basis of very limited information from 48 patients, gabapentin appears to be effective for treatment of RLS.
References
ML Thorpe et al. A crossover study of gabapentin in treatment of restless legs syndrome among hemodialysis patients. American Journal of Kidney Diseases 2001 38: 104-108.
D Gargia-Borreguero et al. Treatment of restless legs syndrome with gabapentin. A double-blind, crossover study. Neurology 2002 59: 1573-1579.
S Happe et al. Gabapentin versus ropinirole in the treatment of idiopathic restless legs syndrome. Neuropsychobiology 2003 48: 82-86.
Trials
Details of the trials are shown in Table 1. One investigated patients with RLS and renal disease, while the other two investigated RLS without secondary cause.
Results
There are only 48 patients treated with gabapentin in these three trials. In the most relevant (Garcia-Borreguero), about two-thirds of patients had only mild symptoms with treatment. The open study by Happe et al did have a longer-term result, showing that patients on both gabapentin and ropinirole were still doing well some months later. The dose in the small study in patients on haemodialysis was only 900 mg a week, compared with an average of 2,000 mg a day in patients with normal renal function.
Table 1: Clinical trials of gabapentin
| Thorp et al. Am J Kidney Dis 2001 38: 104-108 | R = 1 DB = 1 WD = 1 QS = 3 Crossover Duration = two six week periods |
Treatments 1 Gabapentin 300 mg three times weekly at end of haemodialysis (16) 2 Placebo (16) Outcomes Patient scales of subjective symptoms |
Mean age 64 (range 51 to 74). Patients on haemodialysis three times a week | Using score of six out of maximum of eight points to define effective: 11/13 effective with gabapentin 1/13 placebo |
2/16 withdrew because of somnolence and lethargy on gabapentin 1/16 died of MI on placebo |
| Garcia-Borreguero et al. Neurology 2002 59: 1573-1579 | R = 2 DB = 2 WD = 1 QS = 5 Crossover Duration = two six week periods |
Treatments 1 Gabapentin up to 2,400 mg daily (24) 2 Placebo (24) Outcomes RLS rating using questionnaire, and sleep measurements |
Mean age was 55 years (33-75), two-thirds women | By week 6, 16/24 on gabapentin had mild RLS symptoms, compared with 8/24 on placebo. RLS symptom score fell with gabapentin, but not placebo. Sleep and pain also improved with gabapentin. There were no cases of augmentation | All cause withdrawals, 2 on placebo, 1 on gabapentin, none treatment related 12/24 on gabapentin and 4/24 on placebo had at least one drug-related adverse event |
| Happe et al. Neuropsychobiology 2003 48: 82-86 | R = 1 DB = 0 WD = 0 QS = 1 Parallel group Duration = four weeks |
Treatments 1 Gabapentin 300-1200 mg daily (8) 2 Ropinirole 0.25-1.5 mg daily (8) Outcomes Questionnaires and sleep studies |
Mean age about 60 years, duration of RLS 16 years | All patients reported that RLS symptoms had improved or disappeared | Some mild and transient adverse events were seen in both groups. There were no serious adverse events, or discontinuations because of adverse events |
The largest and best study comparing gabapentin at a final mean dose of 2000 mg daily with placebo after eight weeks of treatment reported RLS symptoms at the end of treatment according to their severity (Figure 1). More patients on gabapentin had only mild symptom severity.
Figure 1: Symptom severity after six weeks of gabapentin or placebo
Adverse events appeared to be mild and transient.
Comment
On the basis of very limited information from 48 patients, gabapentin appears to be effective for treatment of RLS.