Riluzole (oral)

Riluzole is a glutamate antagonist that decreases the level of glutamate in the body and can prolong the lives of patients diagnosed with ALS.

Overview

Riluzole is a drug in the benzothiazole class that is used to treat patients who have been diagnosed with amyotrophic lateral sclerosis (ALS). It works by reducing the level of glutamate in a patient’s body. Glutamate is an amino acid that impacts on the nerves that relay messages between the brain and muscles. Patients suffering from ALS have been found to have extremely high glutamate levels, which can lead to nerve cell damage.

While riluzole cannot be considered a cure for ALS, it may be able to slow the development of the disease and lead to both a prolonging of life expectancy and an extension of the time before a tracheostomy is required. Riluzole has been found to extend survival and the period before a tracheostomy becomes necessary by roughly two months. One study has found that riluzole can produce a nine percent increase in the probability of a patient surviving one year, while another analysis found that it provided a notable survival advantage at six, nine, twelve and fifteen month time points, though not at the eighteen month point.

Riluzole is the sole approved treatment in the case of ALS by both the FDA in the United States and NICE in the UK. It has also been found to have antidepressant properties and has been associated with some improvement in cases of refractory depression, as well as mood and anxiety disorders and obsessive-compulsive disorder.

Conditions Treated

  • Motor Neurone Disease
  • Depression
  • Generalized Anxiety Disorder
  • Obsessive Compulsive Disorder

Type of Medicine

  • Glutamate Antagonist

Side Effects

When taking riluzole, patients may experience a number of side effects that will not usually require them to seek medical intervention. Many of these side effects will disappear as your body becomes used to the medicine. If a patient is troubled by any of the side effects detailed below, they can speak to their doctor who may be able to advise on methods to reduce or prevent the unwanted effects.

Riluzole can lead to a number of side effects that don’t require medical attention. These can include abdominal pain, an excessive presence of gas in the stomach, along with a sensation of being full and increased passing of gas. Patients can also experience some swelling of limbs or face, a degree of muscle stiffness, joint pain, a tingling sensation in the hands and feet. Other symptoms may include dry mouth, a degree of dizziness, a feeling of constant movement, unusual sleepiness or difficulty sleeping and unusual weight changes.

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

While the side effects noted above do not require urgent medical consultation, there are more serious side effects, which should prompt the patient to check with their doctor immediately.

The more serious possible side effects of riluzole include an unusually frequent urge to expel urine, bladder pain, urine that is bloody, cloudy or dark, pain or soreness when attempting to urinate or black, tarry-coloured stools. Some patients may also experience heart and lung difficulties, including problems with normal breathing, unusual levels of coughing, and a slowed, quickened or irregular heartbeat.

Other side effects that should prompt a patient to seek medical attention include a persistent headache, pain in the side or lower back, persistent pounding in the ears, tenderness on the upper right side of the body, chills or fever, nausea and vomiting, changes to skin colour, ulcers or white spots in the mouth, a sore throat, nervousness or anorexia, excessive fatigue or weakness and unusual or irregular bruising or bleeding.

Dosage

Patients should always be guided by their doctor when it comes to dosage, and are advised only to take riluzole strictly in accordance with their doctor’s instructions or the directions listed on the packet. The typical doses described below may be varied in the case of some patients and a medical professional’s dosage advice will always take precedence.

The oral dosage for riluzole is typically one tablet of 50 milligrams twice a day for adults. In the case of children, their doctor will advise on the correct dosage level. The tablet has to be swallowed whole and should never be broken, crushed or chewed. It is also important to take riluzole on an empty stomach, so patients are usually advised to take it at least an hour before a meal or two hours after. As the medicine is most effective if there is a constant level of riluzole in the bloodstream, it is important for patients to remember to take the medication at the same time every day without missing a dose.

Patients should always ensure that they take their riluzole medication exactly as instructed and should never take more or less than the prescribed amount, nor should they go without taking it for a longer time than instructed.

If a dose is missed, patients should take it as soon as they remember; however, if they remember the missed dose shortly before their next dose is due, they should not take the missed dose. In no circumstances should a patient take an extra dose. Any questions regarding dosage should be referred to the medical professional charged with treating the patient, as they will be in the best position to advise.

Interactions

When using more than one type of medication, complications can occur. In some cases, it is not advisable to use riluzole in conjunction with another treatment, while in other cases the side effects of taking riluzole with another drug may be significant but tolerable. When beginning a course of riluzole, the patient’s doctor will want to know what other medications a patient is taking and may need to adjust the riluzole dose as treatment continues.

The following medications have been identified as having a potentially significant interaction with riluzole and it may not be advisable to take them in combination. This may not be avoidable but a patient’s doctor should be made aware if a patient takes or is prescribed any of these medications:

  • Dasabuvir
  • Pixantrone
  • Sulfasalazine

In addition to the medications noted above, there are some medications that can cause significant, yet tolerable side effects. In these cases, a patient’s doctor may decide that it is worthwhile taking the drugs in combination, but will adjust the riluzole dose accordingly should the side effects prove intolerable. These medicines include:

  • Tacrine
  • Theophylline

Warning

To ensure that a patient is not at risk of serious harm when taking riluzole, it is vital for them to notify their doctor if they have a number of other medical conditions, whether they are receiving medication for those conditions or not.

The most significant of these conditions is liver disease or any illness associated with the liver. Use of riluzole has been known to lead to liver problems, particularly in women, older patients and those who present with a history of liver disease.

Riluzole can also exacerbate liver problems for patients who are taking other drugs that can be harmful to the liver. These can include any type of antibiotic or antifungal medication, antiviral drugs or any type of medication treating HIV/AIDS; pills taken for birth control or hormone replacement reasons; some types of anti-pain or arthritis medications; seizure drugs including carbamazepine and phenytoin; and statin-type cholesterol-lowering drugs.

Any patient who has liver problems or is taking drugs that can have a negative effect on the liver, should therefore ensure that their doctor is fully aware of these conditions.

Other patients who should be cautious about using riluzole include those suffering from bone marrow diseases such as neutropenia and anyone who has a lung disease such as interstitial lung disease. riluzopole has been known to exacerbate these conditions.

Pregnant women should also be cautious about using riluzole. This medication is classed by the FDA as a pregnancy category C drug. It is not clear from research whether riluzole can cause harm to an unborn child, and it is also not known whether the drug can be passed to a baby through breast milk or can be dangerous to nursing babies. As a consequence, women who are pregnant or who are planning to become pregnant should inform their doctor before starting this medication, and should not breastfeed while taking riluzole.

Finally, it is worth noting that as with many powerful drugs, riluzole can react to certain types of food or other ingested items. The special instructions relating to food and drink while taking this medication advise patients not to drink coffee, cola, tea or any other caffeine-containing product as caffeine can cause an undesirable build-up of riluzole in the patient’s body.

Smoking tobacco should also be avoided by patients taking riluzole as smoking can reduce the effectiveness of the drug. Drinking alcohol while on a course of riluzole can also be a problem, as it can increase the danger of the patient experiencing liver damage. In some patients, riluzole can negatively affect their reaction times and their thinking, so it may be advisable for them to avoid driving or taking part in any activity that requires alertness.

Storage

Riluzole does not require any special temperature-adjusted storage conditions, but the blister pack containing the tablets should be kept in the outer carton to ensure that the tablets are not affected by the light. The container should also be stored in a place that is not unduly affected by heat, freezing cold, humidity, or direct sunlight.

As with other strong medications, it is important not to retain any riluzole tablets that have passed their expiry date or that are no longer required. In the event that a patient is no longer taking the medication or their medication has become out of date, they should contact their doctor for advise on how the drug should be disposed of.

Summary

Currently, riluzole is the sole medication that has been licensed for use in treating ALS, by the Food and Drugs Administration (FDA) in the US and the National Institute for Health and Care Excellence (NICE) in the UK. It works by suppressing the activity and build up of glutamate in the body. Glutamate is a chemical messenger that facilitates the transmission of electrical messages from the brain to the muscles, but in patients with ALS, glutamate builds up in higher concentrations and can be toxic.

The full process by which riluzole helps ALS patients is not yet fully understood, though it has been proven to provide some benefit to those with the condition.

Riluzole cannot be considered to be a cure for ALS patients and it cannot reverse any motor neurone damage that has already taken place. According to research, riluzole may increase survival rates by an average of two to four months after a period of twelve to eighteen months of treatment, although the alleviation of ALS symptoms is not immediately apparent, and those taking the drug may not notice any effect initially.

For the drug to be most effective, it is advisable for patients to start taking it as early as possible after diagnosis with ALS. It can also have significant side effects and risks, most notably for those suffering from liver damage or who are taking medication that can affect the liver, while taking riluzole may also pose a risk to an unborn or newborn baby.

 

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Last Reviewed:
February 01, 2018
Last Updated:
January 27, 2018