The aim of this study is to evaluate the impact of pharmaceutical care on the number of drug-related problems, clinical outcomes and quality of life of patients with Parkinson's disease.

This is a randomized controlled study that will be conducted in Parkinson's disease and movement disorders clinic, Siriraj Hospital, Thailand. The participants and assessors evaluating MDS-UPDRS were blinded in this study.

The participants will be divided into two groups by block randomization: intervention group and usual care group.

For the intervention group, the clinical pharmacists will conduct medication reviews, patient education, and counseling. Moreover, the clinical pharmacists will identify drug-related problems (DRPs) and provide the information through written pharmacist notes to physicians at the clinic. For patients randomized to the control group will attend the medical follow-up as usual and receive usual care. Telepharmacy will be conducted 2-7 days before the doctor visit and within 1 week after the doctor visit. Data collection will be conducted at baseline, week 12, and week 24 in both groups. After the follow-up, the pharmacist will count the number of drug-related problems identified after the doctor visit. The primary outcome of the study is comparing the number of drug-related problems per person changed from the start of the study to the end of week 24 between two groups.

Inclusion Criteria:

1. Age 18 years or older
2. Diagnosed with idiopathic Parkinson's disease according to the UK Parkinson's disease Society Brain Bank Criteria for at least 3 years
3. Modified Hoehn and Yahr stage 2-4
4. Patient had received at least one of antiparkinsonian drugs the following: levodopa, MAO-B inhibitors, dopamine agonists, COMT inhibitors, amantadine, and trihexyphenidyl
5. Patient has given a written informed consent to participate in the study. If the patients are unable to give an informed consent, it must be obtained from the caregiver.

Exclusion Criteria:

1. Patient is unable to communicate via telephone or mobile phone or internet.
2. Patient who is terminal illness
3. Patient who is bed ridden
4. Patient with other movement disorders include corticobasal syndrome, multiple system atrophy, progressive supranuclear palsy and essential tremor
5. Moderate to severe dementia as evidenced by Mini Mental State Examination (MMSE) or Thai Mental State Examination (TMSE) less than 20 and without the caregiver
6. Patient who is planning to undergo surgery or have a history of surgical treatment for Parkinson's disease such as pallidotomy, thalamotomy, or deep brain stimulation
7. Patient with hearing impairments which affects communication via telephone or electronic media
8. Unable to communicate Thai language

The participants and assessors evaluating MDS-UPDRS were blinded in this study