Parkinson’s Medications: A Primer

medication bag with pills

There are many different classes of medications that offer options for people with mild to advanced Parkinson’s symptoms. Treatment discoveries are also progressing at a rapid pace, and new medications are continually added to the growing list.

Typically, Parkinson’s medication treatment is divided into motor and non-motor symptom categories. In this post, we’ll take a look at the different types of Parkinson’s medications, the names of common Parkinson’s medications, and the symptoms that can be managed by using these medications. (And remember, it’s essential that you talk to your physician if your medications aren’t working or you’re interested in trying something new.)

MEDICATIONs FOR MOTOR SYMPTOMS

Levodopa: Levodopa is the gold-standard treatment for Parkinson’s. It was one of the first Parkinson’s drugs, and it is still the main drug prescribed to treat Parkinson’s for many people. It acts tohelp with slowness, stiffness, and tremor. Carbidopa/levodopa can be used in conjunctionwith other medications to address the same symptoms. Carbidopa is now almost always combined with levodopa to enable more levodopa to reach the brain rather than the bloodstream. Common side effects of carbidopa/levodopa include nausea and light-headedness. To see a full list of medications in this category, click here.

Dopamine Agonists: Dopamine agonists address the same symptoms as carbidopa/levodopa, namely slowness, stiffness, and tremor. Dopamine agonists can be used alone or in conjunction with othermedications to address those symptoms. Common side effects include nausea and light-headedness. Over years of use, dopamine agonists are less likely than carbidopa/levodopa to cause dyskinesias or fluctuations with OFF time, but dopamine agonists may not be quite as effective for control of motor symptoms, and certain side effects are more likely with dopamine agonists, including leg swelling, sleep attacks, and compulsive behaviors. To see a full list of medications in this category, click here.

MAO-B Inhibitors: Monoamine Oxidase Type B (MAO-B) inhibitors act to block an enzyme that breaks down dopamine, which allows more dopamine to be available to the brain. Like levodopa and dopamine agonists, MAO-B inhibitors are used to treat slowness, stiffness, and tremor. They can be used on their own, though they typically have a milder benefit than levodopa and dopamine agonists. MAO-B inhibitors are often used as supplemental medications to reduce OFF time. Common side effects include nausea, light-headedness, and insomnia. Because MAO-B inhibitors increase and prolong the effects of dopamine, the side effects of dopamine may also be enhanced, including dyskinesia. There are multiple medications that are contraindicated with MAO-B inhibitors. To see a full list of medications in this category, click here.

Medications and glass of waterCOMT Inhibitors: Catechol-o-methyl transferase (COMT) inhibitors block levodopa metabolism, prolonging levodopa effects. COMT inhibitors thus have no effect on their own and are always used in conjunction with levodopa. COMT inhibitors are used primarily to treat motor fluctuations and reduce OFF time. Possible side effects include diarrhea and discolored urine. Because COMT inhibitors increase and prolong the effects of levodopa, the side effects of levodopa may also be enhanced, including dyskinesia. To see a full list of medications in this category, click here.

Amantadine Hydrochloride: Amantadine can be used alone or in conjunction with other medications to treat slowness, stiffness, and tremor. Amantadine has a unique role in the treatment of Parkinson’s because it is the only medication that allows more treatment of motor symptoms while potentially reducing dyskinesias. People with kidney problems need a decreased dosage. Common side effects include nausea and light-headedness. Possible anti-cholinergic side effects including confusion and constipation. Other possible side effects include leg swelling and a reddish rash known as livedo reticularis. To see a full list of medications in this category, click here.

Anticholinergic Medications: Anticholinergic medications are used to treat tremor and dystonia in people with Parkinson’s. They do this by reducing the amount of acetylcholine, a neurotransmitter that is in balance with dopamine in the body. Anticholinergic medications are also sometimes prescribed to help with drooling. Anticholinergic medications are usually best tolerated by younger people and should be avoided by elderly people with Parkinson’s because they can increase confusion, cognitive slowing, and hallucinations. Other possible side effects include dry mouth, worsening of glaucoma, blurry vision, and urinary retention. To see a full list of medications in this category, click here.

Adenosine receptor antagonists: Adenosine receptor antagonists act to block the reception sites for the neurotransmitter adenosine, which acts as a central nervous system depressant. This medication is approved for use in conjunction with carbidopa/levodopa to help reduce OFF time. These medications can increase ON time without troublesome dyskinesias for many people, but dyskinesias are the most common side effect. To see a full list of medications in this category, click here.

MEDICATIONs FOR NON-MOTOR SYMPTOMS

Parkinson’s-Related Depression and anxiety

Selective Serotonin Reuptake Inhibitors (SSRIs): SSRIs are the most commonly prescribed antidepressants for Parkinson’s-related depression because of their tolerability. These medications can also used to treat anxiety and obsessive-compulsive disorder (OCD). It often takes four to six weeks of a therapeutic dose for full effect. SSRIs are sometimes combined with other medications such SNRIs and TCAs (see tables below), but such combinations should be used with caution due to a potential for serotonin syndrome. Possible side effects include headache, nausea, insomnia, jitteriness, sexual dysfunction, and weight gain. To see a full list of medications in this category, click here.

Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs): SNRIs are another class of antidepressants that can treat depression, anxiety, and OCD. Like SSRIs, it often takes four to six weeks after reaching a therapeutic dose for them to take effect. SNRIs can raise blood pressure, and other possible side effects include headache, nausea, sexual dysfunction, and dizziness. Like SSRIs, SNRIs should be used with caution in conjunction with other serotonergic medications due to a potential for serotonin syndrome. To see a full list of medications in this category, click here.

Tricyclic Antidepressants: TCAs are another class of medications used to treat depression, anxiety, and OCD. They are prescribed less often than SSRIs and SNRIs due to higher likelihood of side effects. Possible side effects include dry mouth, constipation, orthostatic hypotension, urinary retention, and confusion. People with heart conditions (such as arrhythmia or QTc prolongation) should use TCAs with caution. Like SSRIs and SNRIs, it often takes four to six weeks after reaching a therapeutic dose for them to take effect. These medications should be used with caution in conjunction with other serotonergic medications due to a potential for serotonin syndrome. To see a full list of medications in this category, click here.

Medications spilling onto tableOther Antidepressants: Other medications can also have benefit for depression, anxiety, and OCD. Like SSRIs, SNRIs, and TCAs, it often takes four to six weeks after reaching a therapeutic dose for these drugs to take effect. Some of these medications should be used with caution in conjunction with serotonergic medications due to a potential for serotonin syndrome. To see a full list of other antidepressants, click here.

OTHER NON-MOTOR SYMPTOMS

Constipation: One of the most common non-motor symptoms of Parkinson’s, constipation can severely affect quality of life. Lifestyle changes like increasing water, increasing dietary fiber, and increasing exercise are the cornerstones of treatment. Lowering medications that may have anticholinergic side effects may be necessary. Specific pharmacological interventions are also available. Common side effects include bloating, gas, upset stomach, and dizziness. To see a full list of medications that can help treat this symptom, click here.

Drooling: Sialorrhea, or excessive drooling, is another common non-motor symptom of Parkinson’s. The medications listed below are used either on- or off-label to address drooling. Side effects vary by treatment, but the most common is dry mouth. To see a full list of medications that can help treat this symptom, click here.

Fatigue: Fatigue means low energy and is a common symptom in Parkinson’s. Fatigue often overlaps with sleepiness and/or depression. Because medication treatment options for fatigue may be of limited benefit, treatment of any overlapping sleepiness or depression is paramount. Lifestyle changes are also important, including budgeting energy for your most important activities, exercising regularly, eating well, drinking lots of water, getting enough sleep, and taking breaks when needed. Spending time with other people helps some people feel more engaged and energetic Medications can have some benefit for fatigue. Possible side effects include headache, dizziness, anxiety, nervousness, and insomnia. To see a full list of medications that can help treat this symptom, click here.

Neurogenic orthostatic hypotension (nOH): nOH, a common symptom of Parkinson’s, refers to a drop in blood pressure when changing position, especially when standing up. nOH is due to the autonomic nervous system failing to maintain blood pressure when changing position. The most common symptom of nOH is light-headedness, but nOH can also cause blurry vision and cognitive changes that are worse when standing up. Non-pharmacological changes can be very effective. These include increasing fluid intake, increasing salt and caffeine intake, wearing compression stockings or an abdominal binder, and raising the head of the bed during sleep. Medications can also improve nOH in people with Parkinson’s. Possible side effects include high blood pressure when lying down (supine hypertension). To see a full list of medications that can help treat this symptom, click here.

Overactive bladder (OAB): The bladder is a muscle, and spasms of the bladder muscle can cause urinary urgency and/ or frequency among people with Parkinson’s. Lifestyle changes can be of some benefit in reducing OAB: weight loss, reducing consumption of alcohol and caffeine, and reducing fluid intake at night. Pelvic floor strengthening with Kegel exercises can be helpful. Medications can also reduce the bladder spasms of OAB. Possible side effects include headache, constipation, dry mouth, blurry vision, and urinary retention. Most OAB medications work via anticholinergic effects, and they can have the side effects of anticholinergic medications. To see a full list of medications that can help treat this symptom, click here.
Alarm clock, pills and a multicolored weekly pill organizer
Pain: Pain is a frequent and often under-recognized symptom of Parkinson’s. Pain can be compounded by other factors including age, arthritis, spinal stenosis, and neuropathy. Lifestyle changes, especially exercising and making your home safer, are important steps for pain reduction and management. Other specialists can be helpful, such as a massage therapist, physical therapist, or acupuncturist. Treatments for motor symptoms in Parkinson’s (like dopamine medications and deep brain stimulation (DBS) surgery) can also reduce pain. Check out our webinar on pain with Dr. Miyasaki’s here to get more information on how to address pain for people with Parkinson’s specifically. To see a list of medications that can help treat this symptom, click here.

Parkinson’s-Related Dementia: Dementia refers to difficulty with thinking and memory that impairs day-to-day function and the ability to live independently. Dementia often develops in people with advanced Parkinson’s. The medications used for Parkinson’s-Related Dementia are cholinesterase inhibitors. This means they increase the amount of acetylcholine, which is involved in thinking and memory. These medications often have a modest benefit. They can also sometimes have benefit in reducing freezing of gait. Note that anticholinergic medications have the opposite effect (they lower acetylcholine), so anticholinergic medications should usually be avoided by a person with Parkinson’s-Related Dementia. These medications are all approved for Alzheimer’s disease, which is a different type of dementia. Possible side effects include nausea, vomiting, diarrhea, dizziness, and tremor. To see a list of medications that can help treat this symptom, click here.

Parkinson’s Disease Psychosis: Hallucinations refers to seeing or hearing things that aren’t there. Delusions refers to believing things that are not true. The presence of hallucinations or delusions is technically known as psychosis. These symptoms may range from mild to severe. Possible side effects include drowsiness, low blood pressure, and constipation. To see a list of medications that can help treat these symptoms, click here.

Sexual problems: Changes in sexual function and drive can occur as part of Parkinson’s, and also possibly as side effects of certain medications, particularly antidepressants. Medications for erectile dysfunction (ED) and lubrication for pain with sex (especially for women experiencing vaginal dryness) can be useful, but often lifestyle changes and alternative therapies are especially effective. Consider scheduling sex for times when your medication is at its most effective or try experimenting to see what other ways you can show affection. Engaging in talk therapy or visiting a specialist (like a gynecologist or urologist) can be helpful as well. Finally, be open with your partner and try not to be embarrassed (especially when talking to your doctor). Sexual problems are very common in people with Parkinson’s and if you don’t disclose them, you won’t be able to address them. Hypersexuality and compulsive sexual behavior are side effects of dopaminergic agonists and can often be treated by reducing dosage. To see a list of medications that can help treat these symptoms, click here.

Medications in dispenserSleep: Sleep problems are prevalent among people with Parkinson’s. Sleep problems including insomnia, Restless Leg Syndrome (RLS), Periodic Limb Movements Disorder (PLMD), Excessive Daytime Sleepiness (EDS), and REM Sleep Behavior Disorder (RBD). Behavioral changes known as good sleep hygiene may be quite helpful for insomnia. Good sleep hygiene includes having a consistent bedtime and wake-up time, using the bed only for sleep, reducing light in the bedroom, not using technology in the hour before sleep, and decreased fluid consumption before bed. Medication may also have a role to play in the treatment sleep problems for people with Parkinson’s, but a combined behavioral and medication treatment plan is often best. To see a list of medications that can help with sleep, click here.

MEDICATIONS TO AVOID OR TO USE WITH CAUTION

It can be challenging to keep track of all your medications, especially if you’re using medications for both motor and non-motor symptoms. However, keeping an accurate up-to-date list of your medications decreases the likelihood of an unwanted medication interaction. Studies have found that one in three people with Parkinson’s have been prescribed contraindicated drugs while they were hospitalized, which highlights the importance of having an up-to-date list of medications available at all times. Learn about medications to avoid or use with caution here.

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