Levodopa, or L-DOPA, is a natural occurring dietary supplement and cycle active drug found in certain kinds of foods and herbs. This substance is synthesized from essential amino acids phenylalanine and tyrosine in the brain. Researchers have identified the biological role it plays and have developed ways of manufacturing the substance in order to treat Parkinson’s disease and other dopamine responsive dystonias.
The symptoms L-DOPA is used to control include trembling, rigidity and slow movements. These are the hallmark signs and symptoms of individuals who suffer from Parkinson’s disease. Interestingly, dopamine itself is ineffective since the chemical does not answer the brain from the blood. In fact, the metabolic precursor, L-DOPA, does not enter the brain via the bloodstream and is why Levodopa is considered the gold standard for treatment in individuals who have dystonia.
L-DOPA is converted to dopamine in the brain and remains the gold standard for treating Parkinson’s because of the positive benefits that it has in the functional aspects of individuals who suffer from the condition. Standard preparations for L-DOPA combine Levodopa with Carbidopa to improve the action and reduce the side effects. Although a number of therapies have been developed in an attempt to improve the management of individuals who have Parkinson’s disease, most patients still depend upon Levodopa because of its superior ability to control the symptoms.
Drug interactions include vitamin B6 which is an antagonist to Levodopa. Individuals who have a deficiency in vitamin B6 can be supplemented with low levels (five to 10 mg per day or less). Larger doses of vitamin B6 should be avoided because they allow the Levodopa to metabolize to dopamine and inactivate the drug.
Researchers and doctors have found that there are toxic effects for individuals who take Levodopa either with or without Carbidopa. Individuals who are on this medication to control their Parkinson’s disease symptoms must be aware of the physical and psychiatric side effects which are considerable. Physical side effects include low blood pressure which is a common problem in the first few weeks, particularly if the individual starts out with a dose which is too high. The addition of extra supplements of Carbidopa will reduce the effect to some degree and patients should be encouraged to drink lots of fluids and increase their salt intake to maintain normal blood pressure.
Another physical side effect is arrhythmia, abnormal heart rhythms, and gastrointestinal effects. Individuals have found that taking the drug with food can alleviate the nausea, however the proteins interfere with intestinal absorption and some doctors recommend not eating any protein in order to avoid this interference. The drug can also cause gastrointestinal bleeding which patients must be aware of this and report to their physician immediately.
L-DOPA also has psychiatric and mental side effects which may be experienced, especially in combination with other drugs. Individuals may suffer from confusion, extreme emotional states (particularly anxiety), vivid dreams, visual auditory hallucinations and it will have an effect on both learning and sleeping. Levodopa causes fewer psychiatric side effects than other drugs which are used for Parkinson’s disease and, because many of them occur at night, they must be severe in order for some physicians to have the patient reduce or stop taking the evening dose.
Unfortunately, the effect L-DOPA or Levodopa have on the treatment of individuals with Parkinson’s disease is not long-term. Within four to six years after the start of treatment the effects will last for shorter and shorter periods of time. The debate is ongoing about the cause of this effect. Some theories are that the disease progresses beyond the ability of the drug to control it. Some believe that patients become tolerant to the long term exposure and others believe the brains own dopamine neurons become incapable of storing the dopamine. Some doctors and researchers also believe that Levodopa, although the gold standard for treatment of dyskinesia as a result of Parkinson’s disease, will also accelerate the disease by producing oxygen free radicals which are unstable particles that increase the injury to the brain.
Researchers have found that to reduce the effects of the fluctuation in how the supplementation wears off, patients should maintain as consistent a level as possible. Unfortunately, this process is more difficult than it might seem. Levodopa is poorly absorbed and can remain in the stomach for a long time and it is also affected by the foods which are eaten or the acidity of the stomach.
At this time research is in process to develop strategies to take care of these problems. Some individuals take multiple small doses on an empty stomach throughout the day while others are experimenting with the liquid form of medication that may produce fewer fluctuations.
Individuals should always discuss their side effects and treatment protocols for Parkinson’s disease, or other muscular dystonia conditions, with their primary care physician or neurologist in order to obtain the best treatment protocols to control their symptoms.
Resources:
University of Maryland Medical Center: Parkinson’s Disease
http://www.umm.edu/patiented/articles/what_other_drugs_used_parkinsons_disease_000051_8.htm
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