Nearly 7 years on ...

You can get 2018 raw data from:

Drug usage and cost data for the NHS/England is available at:
Prescription Cost Analysis - England, 218 [PAS] - NHS Digital

As an example of how this data might be used, it allows us to estimate the number of PwP on a particular drug. For instance, entacapone.

The data below is from PrescriptionCostAnalysis2018-Data-CSV
Year,BNF Code,Drug Name,BNF Chemical Name,BNF Chapter Name,BNF Sub Paragraph Name,BNF Chapter,BNF Section,BNF Paragraph,BNF Sub Paragraph,Standard_Quantity_Unit ID,Prep_Class_ID,Items,Of which_Class 2_Items,Quantity,NIC (£),NIC Per_Item (£),NIC Per_Quantity_(£),Quantity_Per Item

We are concerned with "Items dispensed ... Each single item written on the form is counted as a prescription item. If a prescription form includes three medicines it is counted as three prescription items." A prescription will typically be for a month.

Summing all the entries for different doses etc., gives 48,489 prescriptions for entacapone on its own and 168,190 prescriptions for levodopa/carbidopa/entacapone (such as Stalevo and its generics). Assuming that people who are on it do so for the whole year (12 prescriptions), that suggests that about 18,000 PwP are on entacapone one way or another, which is about 15% of PwP in England.

I append the raw data so that people can do their own analyses.

John

2018,0409010V0AAAAAA,Entacapone_Tab 200mg,Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,1,47637,0,4193677,561551 .49,11.788137162,0.1339043255,88.034028171
2018,0409010V0AAACAC,Entacapone_Liq Spec 200mg/5ml,Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,3,1,21,0,8700,10206.71,486 .03380952,1.1731850575,414.28571429
2018,0409010V0BBAAAA,Comtess_Tab 200mg,Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,831,0,111399,64004.89, 77.021528279,0.5745553371,134.05415162

2018,0409010X0BBAAAA,Stalevo_Tab 50mg/12.5mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,5195.4,399.4,438186.1, 303690.916,58.453808369,0.6930637827,84.341167186
2018,0409010X0BBABAB,Stalevo_Tab 100mg/25mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,34869.7,1224.7,3352239 .9,2323334.742,66.629043037,0.693069354,96.1361841 37
2018,0409010X0BBACAC,Stalevo_Tab 150mg/37.5mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,26715.8,1180.8,2384172 .9,1652408.264,61.85134879,0.6930740065,89.2420552 63
2018,0409010X0BBADAD,Stalevo_Tab 200mg/50mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,13142.7,416.7,1159376. 9,803523.959,61.138423535,0.6930653517,88.21451452 1
2018,0409010X0BBAEAE,Stalevo_Tab 75mg/18.75mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,8010.7,223.7,732662.4, 507779.901,63.387706567,0.6930612257,91.460471619
2018,0409010X0BBAFAF,Stalevo_Tab 125mg/31.25mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,23816.8,1042.8,2228919 .2,1544768.831,64.860469543,0.6930573486,93.586006 516
2018,0409010X0BBAGAG,Stalevo_Tab 175mg/43.75mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,9267.8,419.8,764486.3, 529836.082,57.16956365,0.6930615787,82.488433069
2018,0409010X0BCAAAF,Sastravi_Tab 125mg/31.25mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,4876.4,213.4,449357.2, 162211.349,33.26456997,0.3609853119,92.149372488
2018,0409010X0BCABAA,Sastravi_Tab 50mg/12.5mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,1245.5,113.5,89992.2,3 3515.79,26.909506222,0.3724299439,72.253873946
2018,0409010X0BCACAE,Sastravi_Tab 75mg/18.75mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,1927.7,54.7,174856.1,6 2004.931,32.165238886,0.3546054784,90.707112103
2018,0409010X0BCADAB,Sastravi_Tab 100mg/25mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,6924.6,247.6,673796.1, 240439.053,34.722446495,0.3568424528,97.3046963
2018,0409010X0BCAEAC,Sastravi_Tab 150mg/37.5mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,4637.4,208.4,406503.2, 146511.97,31.593558891,0.3604202132,87.65756674
2018,0409010X0BCAFAG,Sastravi_Tab 175mg/43.75mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,1648.6,74.6,160832.5,5 7741.796,35.024745845,0.3590182084,97.557018076
2018,0409010X0BCAGAD,Sastravi_Tab 200mg/50mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,2996.5,88.5,258174.1,9 2269.699,30.792490906,0.357393321,86.158551644
2018,0409010X0BDAAAE,Stanek_Tab 75mg/18.75mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,1674.6,46.6,163759.5,5 7994.609,34.631917473,0.3541450053,97.79021856
2018,0409010X0BDABAD,Stanek_Tab 200mg/50mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,2556.8,77.8,210386.9,7 5406.842,29.492663486,0.3584198541,82.285239362
2018,0409010X0BDACAG,Stanek_Tab 175mg/43.75mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,1383.7,62.7,134482.1,4 8384.241,34.96729132,0.3597820156,97.190214642
2018,0409010X0BDADAC,Stanek_Tab 150mg/37.5mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,4806.9,213.9,459090.9, 165022.788,34.330397554,0.3594555849,95.506646695
2018,0409010X0BDAEAA,Stanek_Tab 50mg/12.5mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,1067.1,86.1,93969.6,34 559.584,32.386453003,0.3677740886,88.06072533
2018,0409010X0BDAFAB,Stanek_Tab 100mg/25mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,6353.7,226.7,621967,22 1687.795,34.891133513,0.3564301563,97.890520484
2018,0409010X0BDAGAF,Stanek_Tab 125mg/31.25mg/200mg,Levodopa/Carbidopa/Entacapone,Central nervous system,Dopaminergic Drugs Used In Parkinsonism,04,09,01,0,1,3,5071.8,222.8,451338.5, 162879.099,32.114653377,0.3608801354,88.98980638