Providing resources and ideas for therapies and medical developments for Parkinson's disease:
The following are a list of drugs approved to treat the symptoms of Parkinson's disease, primarily the tremors often refered to as "Motor Fluctuations". Note that none of the drugs approved by the FDA for treating Parkinson's disease are cures, nor do they slow down or halt the progression of the disease. By contrast, there are many drugs in development and drugs in clinical trials which hold hope for such a treatment. Currently the most popular treatments for Parkinson's are the Levodopa based drugs blended with Carbidopa to improve longevity of the drug in one's system. Levodopa can be also be complimented with a Dopamine Agnost, a COMT inhibitor or a MAO inhibitor medication. The drugs effects are often refered to as "On time" where the drugs take effect vs "Off time" when the drug effects are wearing off and less effective.
Drugs are refered to by their "corporate brand name" and by their "generic name".
Levodopa is combined with other drugs like Carbidopa to improve half life, absorption and efficacy. Carbidopa prevents the conversion of Levodopa into dompamine while in the blood stream so that levodopa can make the journey to the brain for conversion where it is needed. When high doses are taken, the peak medication levels of Levodopa may produce involuntary movements known as dyskinesia. Another condition is dystonia, when your muscles continuously contract (cramping), which may cause parts of your body to twist. This leads to repetitive movements or abnormal postures (for example curling of the toes or turning of the foot or ankle) and can cause great pain and discomfort. Both dyskinesia and dystonia often occur at peak doses.
Levodopa has the ability to cross the blood-brain-barrier to reach the aflicted nigral dopaminergic neurones.
Levodopa is the precursor used by the body to generate dopamine within the nigral neurons in the brain (by a reaction with aromatic amino acid decarboxylase - ACC), which then acts as a neurotransmitter.
Various versions of Levodopa based drugs exist. Here are the top five:
Tip: drink lots of water with every dose to help push it along from the stomach to the first part of the intestine when it can be absorbed. Levodopa does not get absorbed in the stomach (ref).
Also see Mid Stride - probably the best resource on carbidopa/levodopa drugs.Levodopa Side Effects and Risks:
In general medical terms, an agonist is a drug which can combine with a receptor on a cell to produce a physiologic reaction typical of a naturally occurring substance. The drug acts along a normal and natural pathway.
A dopamine agonist acts like dopamine by performing the same communications neurotransmitter function in the brain. This class of drug may have bad withdrawal effects. Side effects include hallucinations and excessive daytime sleepiness. Levodopa is often added if the patient's symptoms are not being controlled adequately. Dopamine agonists are effective in prevention and treatment of motor complications. Often the initial drug of choice in young and biologically fit older patients.
COMT (catechol-O-methyltransferase) is an enzyme which degrades dopamine. Drugs listed here are used to block COMT so that dopamine is retained. Used with Levodopa to make it more effective by inhibiting the break-down of dopamine.
(early treatment) therapeutic agents for panic disorder and social phobia. Targets MAO-B thus affecting dopaminergic neurons. MAO-B is a protein which enables the break-down of excess dopamine thus inhibiting MAO-B allows for more dopamine to be available thus helping Parkinson's patients. MAO-B is also a participant in the production of GABA in astrocytes (nutritional bridge between the blood supply and neurons) which is involved in stress and neurotransmitter inhibition leading to dormant neurons. Thus a MAO-B inhibitor reduces GABA, stress and neurotransmitter inhibition. Reversible inhibitors of monoamine oxidase A (RIMAs) are a subclass of MAO inhibitors and are considered to be a safer alternative (ref). MAO-A is also known to affect carcinogenesis.
The Adenosine A2A receptor has been shown to interact with Dopamine receptor D2. The Adenosine receptor A2A can be used to decreases activity in the Dopamine D2 receptors thus affecting dopamin flow.
Used to treat the side effects of high doses of levodopa.