Tizanidine is a skeletal muscle relaxant, used as an anti-spastic medication for a range of conditions, or sometimes used off-label for its analgesic and sedative effects in pain conditions and insomnia. Tizanidine can be safe and effective when used as prescribed. However, the misuse or abuse of tizanidine can result in dangerous effects, withdrawal, or overdose.
- Tizanidine is a medication available only on prescription that can be used to treat a range of conditions.
- Tizanidine can cause side effects, although it is generally a safe and effective treatment.
- Misusing tizanidine can lead to addiction, dependence, withdrawal, and other harmful consequences.
Understanding tizanidine
Tizanidine is a skeletal muscle relaxant that acts as an alpha-2 agonist. It is used in the treatment of various conditions to help manage muscle spasms and pain. [1]
Tizanidine is available as a tablet, capsule, and oral liquid solution. It is usually prescribed to be taken in divided doses up to three times per day. Tizanidine can cause side effects, particularly at the start of treatment. Doctors typically start tizanidine on a low dose to help reduce side effects, which can be gradually increased as needed. [2]
Brand names
Tizanidine is available as a generic medication and as branded medications such as Ontralfy and Zanaflex. [2]
Tizanidine uses
Tizanidine is approved by the Food and Drug Administration (FDA) for the management of spasticity in the context of various conditions. Spasticity is a symptom of neurological conditions such as stroke, multiple sclerosis, traumatic brain injury, or cerebral palsy, and can cause stiffness and pain in the muscles and movement difficulties. [1]
Tizanidine is also shown to be an effective treatment for off-label purposes, including chronic pain conditions such as neck and lower back pain, and musculoskeletal pain conditions. It can be prescribed off-label for migraines and insomnia, and has also shown some promise in the management of acute opioid withdrawal symptoms, though more research is needed. [1][3]
How tizanidine works
Tizanidine works by reducing central nervous system activity to slow and relax the muscles. It is an alpha-2 receptor agonist, meaning that it creates presynaptic inhibition of motor neurons. This reduced the release of amino acids such as glutamate and aspartate, which are associated with muscle spasms. [1]
Alpha-2 receptor agonist activity also inhibits the release of norepinephrine. This causes other changes to sympathetic nervous system activity, including reduced blood pressure, sedating effects, and pain relief. [1][4]
Side effects
It is common to experience side effects when starting tizanidine treatment or when the dosage has been increased. Typically, these side effects are mild and last a short time before going away on their own. However, sometimes they can be more severe and persistent and may require a change in dosage or medication. [2]
Common side effects of tizanidine include: [2][5]
- Drowsiness.
- Tiredness.
- Weakness.
- Dizziness.
- Dry mouth.
- Constipation.
- Nausea and vomiting.
- Increased urination.
- Nervousness.
Severe side effects
In some cases, serious side effects of tizanidine can occur, particularly with higher doses. If any of the following side effects emerge, contact a doctor immediately, as it may be necessary to change medication: [2][5]
- Rash or hives.
- Swelling of the face or mouth.
- Trouble breathing or swallowing.
- Extreme fatigue.
- Unusual bleeding or bruising.
- Yellowing skin or eyes.
- Persistent vomiting.
- Vision impairment.
- Hallucinations.
- Stomach pain.
- Flu symptoms.
- Reduced appetite.
Tizanidine can interact with other substances, particularly other central nervous system (CNS) depressants, causing potentially dangerous effects. It can also be more likely to cause adverse effects in certain populations, including pregnant or breastfeeding people, children and older adults, and people with liver or kidney conditions. [5]
Tizanidine overdose
Taking more tizanidine than prescribed can result in a dangerous or even fatal overdose. This risk is higher if tizanidine is used in combination with other substances, particularly other CNS depressants such as opioids, alcohol, or benzodiazepines. Signs of a tizanidine overdose can include: [2][5]
- Feeling extremely tired and weak.
- Confusion.
- Trouble breathing.
- Slowed heartbeat.
- Dizziness.
- Fainting.
- Loss of consciousness.
If a tizanidine overdose is suspected, call 911 immediately.
Tizanidine addiction
Tizanidine has a low risk of addiction and/or abuse and, therefore, is not a controlled substance. However, some people might misuse or abuse tizanidine and can develop physical and psychological dependence or addiction. [6]
For example, some people who are prescribed tizanidine for pain might increase their dosage by taking larger or more frequent doses than prescribed, without seeking guidance from the prescribing physician. Some people might seek a tizanidine prescription to take alongside other substances to produce enhanced effects.
Misusing or abusing tizanidine can result in the development of addiction, which can include impacts on professional or personal functioning, drug-seeking behaviors, or changes in mood and behavior. [6][7]
It might lead to the development of physical dependence, although this can also occur with prescribed use. Physical dependence can result in withdrawal symptoms when the medication is stopped, and is more likely after prolonged, high-dose use. [1][5]
Tizanidine withdrawal symptoms
Tizanidine withdrawal syndrome can occur after the medication is stopped and is most common after prolonged and excessive use is rapidly reduced or stopped suddenly. As such, it is advised to reduce the dose gradually when stopping tizanidine. [5] Withdrawal symptoms can include: [5][7]
- Shaking.
- Anxiety.
- Increased heart rate and blood pressure.
- Flushing.
- Sweating.
- Vomiting.
- Fever.
Tizanidine withdrawal symptoms can range from mild to severe and may depend on the duration and amount of use. Severe withdrawal is uncommon and is rarely reported or discussed in scientific literature. However, there are a few reports of its occurrence and the requirement for urgent medical attention. It is more likely with the long-term use of high doses, followed by abrupt discontinuation. [6][7][8]
Tizanidine withdrawal timeline
Withdrawal symptoms can begin within 12-24 hours of the last dose, and symptoms are usually the strongest during this time. While rare, severe symptoms are possible, and if present, may require medical treatment to prevent dangerous or fatal effects. Such treatments may include: [6][7][8]
- Acetaminophen to manage fever
- Alpha- and/or beta-blockers to reduce blood pressure
- Benzodiazepines to manage agitation
Additionally, the reintroduction of tizanidine can be necessary to manage severe withdrawal. It is advised to recommence tizanidine on a lower dose than before and schedule a gradual taper. Withdrawal symptoms can improve significantly almost immediately after tizanidine reintroduction, and vital signs can typically be stabilized within 24-48 hours. [7][8]
Treatment options for tizanidine dependence
Tizanidine misuse and addiction may negatively impact functioning in various aspects of life, including professional or academic performance and social relationships.
It can also mean that people who require the medication to manage their symptoms use their prescription faster than intended, leading to unmanaged or worsening symptoms.
People who misuse or are addicted to tizanidine may require professional support to reduce or stop their use and manage addictive behaviors and associated effects. Consulting with a physician can help determine a safe and appropriate taper schedule or alternative medication to manage symptoms.
Additionally, it can be helpful to use substance use disorder services and interventions, such as therapies, counseling, and support groups, to adapt behaviors and manage underlying psychological issues.
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