Parkinson's Disease Treatment Drugs: What Are They?
, genetic factors, female sex, exposure to exogenous and environmental toxins and other factors related to the environment in which one lives, etc.
The main cause of the clinical manifestations of Parkinson's seems to be the reduction of dopaminergic transmission due to the degeneration of neuronal cells present in the substantia nigra of the brain., and then gradually spread to all parts of the body. In Parkinson's disease, the muscles that govern expressive and cognitive capacity are also involved. Parkinson's disease can also cause marked uncoordination or a "total inability to coordinate the various movements.
The most recurrent symptoms are: akathisia, akinesia, impaired intellectual abilities (advanced stage), apraxia, bradykinesia, depression, inappetence, hypomimia, constipation.For further information: Parkinson's Disease Symptoms and to eat according to what is dictated by the rules of food education.
Returning to drug therapy, medicines can improve and alleviate the symptoms that distinguish Parkinson's disease, but they cannot definitively cure the patient. It should also be considered that every organism responds subjectively to therapy, therefore it is not certain that an effective drug in one patient produces the same therapeutic effect in all patients.
As mentioned above, a lack of dopamine is observed in the brains of Parkinson's disease patients: it would be spontaneous to think that the direct administration of this neurotransmitter can be miraculous. But this is not the case: pure dopamine, in fact, is unable to reach the brain, because it does not cross the blood-brain barrier. In place of dopamine, it is possible to take levodopa (L-DOPA), its precursor, able to cross this barrier and therefore reach the brain, where it exercises its therapeutic activity.
In addition to L-DOPA, the most effective drug for Parkinson's disease, dopamine agonists, MAO inhibitors, catechol o-methyltransferase, anticholinergics and glutamate blockers are used in therapy.
It has been observed that Parkinson's disease can be corrected the better the faster the diagnostic assessment and the start of therapy: in fact, the latest generation therapy also and above all aims at the protection of nerve cells, subjected to oxidative insults.
The information on medications for the treatment of Parkinson's disease is not intended to replace the direct relationship between the health professional and the patient. Always consult your doctor and / or specialist before taking any product or drug for the treatment of Parkinson's disease.
Here are some of the drugs most commonly used in Parkinson's disease therapy; however, it is up to the doctor to choose the most suitable active ingredient and dosage for the patient, based on the severity of the disease, the state of health of the patient and his or her response to treatment.
This active ingredient is by far the most used in therapy for Parkinson's disease, as well as being the most effective for treating symptoms. When taken orally, the drug is able to cross the blood-brain barrier and, upon reaching the brain, turns into dopamine.
Levodopa is always available in combination with other active ingredients, such as carbidopa and "entacapone. The latter belongs to the class of COMT inhibitors (see below), while carbidopa prevents levodopa from transforming into dopamine before reaching the brain (remember briefly that dopamine taken from the outside is ineffective because it cannot pass the BEE).
The dosage must be adjusted during the course of therapy: in fact, the progressive loss of therapeutic efficacy is typical of this drug. Among the most common side effects are dyskinesias and hypotension.
Dopamine Agonists (Dopaminergic Drugs)
These drugs are able to mimic the effects of the endogenous neurotransmitter dopamine, the decrease in transmission of which, as we have said, is believed to be the main cause of the clinical manifestations of Parkinson's disease.
Administration of these drugs in the context of Parkinson's disease is not effective in the long term. Among the side effects, we remember: hallucinations, hypotension, water retention and sleepiness.
Among the active ingredients belonging to this group of drugs that can be used in the treatment of Parkinson's disease, we remember:
- Pramipexole (administered orally and can be used either alone - in the early stages of the disease to delay the onset of levodopa use - or in combination with levodopa when the effect of the latter wears off or becomes discontinuous with onset of fluctuations in the therapeutic effect);
- Rotigotine (also used at the beginning of the treatment of the disease in monoterpaia or during the disease in combination with levodopa when its effectiveness is reduced or fluctuations of the therapeutic effect arise);
- Ropinirole (used in the same ways as the active ingredients indicated above);
- Apomorphine (administered parenterally to patients with Parkinson's disease for the "on-demand" treatment of motor fluctuations resistant to treatment with levodopa and other dopamine agonists).
MonoAmino Oxidase Inhibitors (MAOIs)
These drugs help to prevent the breakdown of natural dopamine (synthesized by the body) and that taken in the form of levodopa. This therapeutic activity is possible through the inhibition of the activity of monoamine oxidase B or MAOI-B enzymes (enzymes that metabolise dopamine in the brain) Side effects include: hallucinations, confusion, headache, dizziness.
Among the active ingredients belonging to the group of monoamine oxidase that can be used in the treatment of Parkinson's disease we find:
- Selegiline (used both as monotherapy without levodopa and in association with the latter in patients with end-of-dose fluctuations);
- Rasagiline (used as selegiline);
- Safinamide methanesulfonate (used in patients with Parkinson's disease as adjunctive therapy at a stable dose of levodopa alone or in combination with other Parkinson's drugs).
Catechol-O-Methyl Transferase (COMT) Inhibitors
These are drugs indicated to prolong the therapeutic effect of levodopa-carbidopa by interacting with and blocking the enzyme that destroys levodopa. Among the active ingredients used against Parkinson's disease we mention:
- Entacapone (used in combination with levodopa and benserazide or levodopa and carbidopa in patients with daily "end-of-dose" fluctuations that cannot be stabilized by previous combinations);
- L "opicapone (same use as entacapone);
- Tolcapone (a potent but extremely dangerous drug for liver damage resulting from its administration, is mainly used in combination with levodopa and benserazide or levodopa or carbidopa in patients who have not responded to treatment with other COMT inhibitors).
Derivatives of Ergot
The synthetic and semisynthetic derivatives of ergotine they are not first choice drugs in the treatment of Parkinson's disease; however, your doctor may decide to prescribe them if he deems it necessary. Among the active ingredients that can be used in this sense, we find:
- Bromocriptine (particularly useful in patients who show a decreasing therapeutic response to levodopa);
- Cabergoline (second choice drug for Parkinson's patients who are intolerant to drugs not derived from ergotamine or who have not responded to treatment with them).
Drugs to Reduce Tremors and Dyskinesias
In this group we find:
- Amantadine: is able to increase the extracellular concentration of dopamine, consequently increasing its transmission. Furthermore, it shows synergistic effects with L-dopa and is able to inhibit the release of acetylcholine mediated by the NMDA receptor and can therefore induce anticholinergic effects. It is mainly used in patients with marked dyskinesias.
- Trihexyphenidyl: is characterized by a strong central anticholinergic action and is indicated for the treatment of postencephalic Parkinson's disease. It reduces both the tremor and the stiffness of the patients.
In addition to the administration of the drugs described above, it is possible to follow a parallel therapy for the control of secondary symptoms and to improve the patient's quality of life. In this sense, depending on the case, the doctor may decide to prescribe:
- Anticholinesterase drugs such as rivastigmine for the symptomatic treatment of mild to moderate dementia in patients with Parkinson's disease;
- Medications for treating depression;
- Medicines for the treatment of anxiety;
- drugs for the treatment of constipation.