Large differences in levodopa dose requirement in Parkinson's disease: men use higher doses than women

The characteristics of levodopa dosing are not well described in the literature. The aims were to investigate the use of levodopa in a nationwide Swedish survey and to study the characteristics of low-dose and high-dose patients with Parkinson's disease (PD) in a university hospital.

Patients with >or= 1 and >or= 2 purchases of levodopa during 2007 were selected from the prescribed drug register. Daily levodopa doses were estimated. Records of 504 patients with PD who visited the neurology clinic at Uppsala University Hospital during 2006-2007 were examined to select a low-dose group (< or = 400 mg levodopa daily, n = 21) and a high-dose group (>or= 1200 mg daily, n = 26) with at least 5 years of PD duration.

In total, 33 534 levodopa users with > or = 1 levodopa purchase were found. Daily levodopa dose range was large; median daily dose was 465 mg for men and 395 mg for women (P < 0.0001). Almost half (46%) of the patients used < 400 mg levodopa daily. Significantly, more men were treated with doses >or= 1200 mg daily. Dose and age correlated negatively (P < 0.0001). Patients with high dose at 5 years PD duration continuously increased their dosage the following years, whereas low-dose patients did not. The occurrence of dyskinesias was about the same in both groups despite the large difference in levodopa dose.

We conclude that the levodopa requirement in PD ranges considerably, and that men use higher levodopa dose than women. Levodopa requirement is constant during the progression of the disease in low-dose patients but increases in high-dose patients.