5 Secrets to success when taking levodopa for Parkinson's disease

This week on the Parkinsonsecrets.com blog, we are highlighting an essential aspect of the treatment of Parkinson’s disease-tips (and tricks) to improve the effectiveness and tolerability of the current “gold standard” medication for Parkinson’s disease treatment: levodopa (either with carbidopa or benserazide).

Who is Abhishek Lenka?

This blog was written by Dr. Abhishek Lenka, MD, Ph.D. who completed his medical training at S.C.B Medical College, Cuttack, India, after which he pursued a Ph.D. in Clinical Neurosciences at the National Institute of Mental Health and Neurosciences (NIMHANS). During his Ph.D., he was closely involved with patients with Parkinson’s disease; his research focus was identifying biomarkers for psychosis . He subsequently completed a Neurology residency in the combined training program of Georgetown University in Washington, DC, and the NIH/NINDS, Bethesda, MD. Dr. Lenka has recently moved to Baylor College of Medicine, Houston, TX, for a fellowship in Movement Disorders and plans to continue his research in Parkinson’s disease. He is a person who has observed Parkinson’s disease from three angles; 1- as a caregiver for his father, 2- as a clinician, and 3- as a researcher. Dr. Lenka provides insightful and practical tips to enhance the effectiveness and tolerability of levodopa use in Parkinson’s disease. His work is modified from a recently published in Expert Review of Neurotherapeutics with Dr. Joseph Jankovic.

When should I take the medication: before, with or after meals?

This is a frequently asked question in our clinics. Undoubtedly, taking levodopa/carbidopa tablets on an empty stomach results in better and faster absorption of the drug. However, having an absolute “empty stomach” is not always feasible, especially when patients with Parkinson’s disease require three-to-four-times per day dosing of levodopa/carbidopa. Therefore, the drug should ideally be taken 30-40 minutes before a meal. Furthermore, it has been demonstrated that food rich in protein blunts the effect of levodopa due to poor absorption. Hence, it would be ideal to not ingest meat, cheese, milk and other protein-rich food or drinks immediately just before or after taking levodopa/carbidopa.

Suppose you are experiencing side effects such as nausea and vomiting after taking levodopa/carbidopa on an empty stomach—in that case, you may have to take the medication after a very light snack (such as a cracker) and with the addition of water. While initiating treatment with levodopa, some neurologists advise “taking” it after meals— to prevent the side effects. This will have effects on absorption.

I have an excellent response to levodopa/carbidopa. The last few weeks, the response has been minimal. Could this be related to issues with my gastrointestinal system?

This is a common issue that we encounter in the clinics. Abnormal motility of the gut is a common non-motor symptom of Parkinson’s disease, and it may inhibit the absorption of levodopa in the small intestine. In such cases patients may report that dyskinesia has also “stopped” for a few days/weeks (due to suboptimal blood levels of levodopa in the setting of poor absorption). Abnormal stomach and gut motility is also termed “gastroparesis”. If you face a similar situation, you should be in touch with your neurologist, and it may also be helpful to discuss the issue with a gastroenterologist. If you are experiencing constipation— treatment may improve levodopa absorption. To objectively measure the degree of gastroparesis, your gastroenterologist may request a test called a “gastric emptying study.” Some medications (collectively known as “pro-kinetic agents”) may improve gastroparesis. This class includes domperidone, cisapride, mosapride, erythromycin, and pyridostigmine. However, these should be tried only after discussion with a gastroenterologist or neurologist.

Some patients report a better response when they take levodopa/carbidopa along with a small amount of a carbonated beverage. This is probably because carbonated beverages result in faster disintegration of the tablet and help in a more rapid absorption from the small intestine. It has been shown that dissolving the levodopa in a vitamin C solution and sipping it may also improve absorption (orange juice is commonly used). You may consider these options and also consider long term a gastroenterology consultation.

Am I at the risk of having hypotension (low blood pressure) every time I take my doses of levodopa/carbidopa?

It was previously thought that levodopa always results in low blood pressure; especially when patients change from the sitting/supine position to standing position; however, several recent studies have challenged that theory. In fact, many patients with Parkinson’s disease have autonomic dysfunction, which results in a drop in blood pressure in the standing position (without levodopa). Therefore, if you have symptoms of low blood pressure (dizziness, mental cloudiness), you and your health care professional should document your blood pressure in supine (laying down) and standing positions. You may possibly decide to continue taking levodopa— however you may also require higher amounts of hydration, using compression leg stockings (or an abdominal binder) and increasing daily salt intake— all strategies to prevent the drop in blood pressure if it occurs. In rare cases you may need a tilt-table test and referral to an autonomic disorder specialist.

In general as Parkinson progresses and you take levodopa; this combination can lead to lower blood pressure and may require medication or other management strategies.

I see two different carbidopa dosing options: 10 mg or 25mg: Both are combined with levodopa. Which option is better?

While the primary Parkinson drug is levodopa, the levodopa needs some help from carbidopa to reach your brain. Without carbidopa it will not work as well and it will stay in the gut— meaning more side-effects . The standard has been to take at least 75 mg of carbidopa per day, however every case is different. In general it translates to mean that if someone takes levodopa/carbidopa 3-4 times per day, a 25 mg formulation of carbidopa would be ideal. However, the same goal would not be achieved with 10 mg formulations (it will require 7-8 times/day of medication intake— which is usually not practical). Therefore, the 25 mg formulation of carbidopa is preferred over 10 mg formulation in most circumstances. Some experts have argued that the 10mg could be tried in brittle dyskinesia where perhaps getting less to the brain may possibly be an advantage. In practice the 10mg is rarely used.

Is it common to feel drowsy and confused after starting levodopa/carbidopa?

Levodopa does have some central nervous system side effects including drowsiness and confusion. If present, these symptoms usually resolve within a few days. However, if you are taking levodopa and you continue to experience these side effects— you may consider discussing with your neurologist (or general practitioner) a possible reduction in the dose of the medication—or a plan for a slower “up-titration” (increase in medicine). In addition, you should be “mindful” of other common issues that may emerge and possibly be related to or affected by the levodopa: confusion, infections, sleep disturbances, fluid/electrolyte imbalances and dehydration.