Benserazide is used in the treatment of Parkinson's disease.

Benserazide is always given with levodopa. It works by preventing levodopa from being broken down before it reaches the brain. This allows for a lower dose of levodopa, which causes less nausea and vomiting.

Nausea, Postural hypotension (low blood pressure), Psychiatric disturbances, Abnormal heart rhythm, Abnormal involuntary movements, Altered libido, Anemia, Drowsiness, Fluctuating disability, Hallucination, Decreased blood pressure, Decreased white blood cell count, Increased liver enzymes, Reduced blood platelets, Vomiting

• Inform your doctor if you are going to have an operation. You may be asked to stop this medication before administering general anesthetic. • Tell your doctor if you have been advised to undergo any laboratory test as this medicine may affect the results of some tests. • Use effective methods of contraception while taking this medication to avoid pregnancy. • Do not stop taking this medicine abruptly without your doctor’s advice. Sudden withdrawal of this medicine may lead to a serious life-threatening condition called as ‘neuroleptic malignant-like syndrome ’, symptoms include increased shaking, sudden high body temperature and muscle problems including stiffness and trouble with balancing. • Do not drive or operate machinery as benserazide may cause dizziness, sudden onset of sleep/excessive sleepiness and visual disturbances. • Should not be given to patients who are allergic to benserazide or any of its ingredients. • Should not be given to patients under 25 years of age. • Should not be given to patients with liver, kidney or heart disease (e.g. uneven heartbeat or heart attack). • Should not be given to patients with hormonal disorders (e.g. overactive thyroid gland). • Should not be given to patients with psychiatric problems which may include anxiety, inability to think and judge correctly, hallucinations etc. or are being treated with anti-depressants (non-selective monoamine oxidase inhibitors. • Should not be given to patients who have a history of or may be suffering from skin cancer. • Should not be given to patients having problems of   pressure in eyes (narrow angle glaucoma). • Should not be given to pregnant women.

Ques. Q. Why is benserazide administered with levodopa?
Benserazide on its own has little therapeutic effect but it works synergistically in combination with levodopa.