Tizanidine, a commonly prescribed muscle relaxer, while effective for its intended use, has been associated with a risk of misuse and dependence. Like many other prescription medications, when mixed with alcohol, CNS depressants, or tobacco products, muscle relaxers can have dangerous interactions.
What is Tizanidine (Zanaflex)?
Tizanidine, sold under the brand name Zanaflex, is a common muscle relaxer used to treat muscle spasms, cramping, and tightness caused by certain chronic pain conditions. This medication is often prescribed for symptom relief for multiple sclerosis, neurological disorders, and spinal cord injuries.
Common Side Effects of Muscle Relaxers
Tizanidine, alongside other common muscle relaxants, comes with various effects. While some side effects and risks may be mild, others can be severe and impact overall health and well-being. The most common side effects of Tizanidine include:
- Tiredness and dizziness
- Weakness
- Lack of energy
- Blurred vision
- Dry mouth
- Nausea and vomiting
- Constipation
- Urinary tract infection (UTI)
- Low blood pressure (hypotension)
- Low heart rate (bradycardia)
Symptoms may differ from patient to patient depending on health status, body composition, and dosage amount. Muscle relaxers can be effective in pain relief. However, some individuals may experience chronic fatigue, dangerous drug interactions, and a higher risk of overdose.
Tizanidine Drug Interactions
Polysubstance use with muscle relaxers, even other prescription medications, can have dangerous interactions. Mixing alcohol, opioids, tobacco products, or blood pressure medications can lead to adverse side effects and health risks. Drug interactions with Tizanidine include:
- Ciprofloxacin (Cipro)
- Fluvoxamine (Luvox)
- Benadryl
- Benzodiazepines
- Opioids (oxycodone, hydrocodone, tramadol)
- Antidepressants
- Other muscle relaxers
- Alcohol
Medications like Luvox and Cipro can block the liver enzymes that metabolize Tizanidine, leading to elevated levels in the blood. Higher Tizanidine levels in the body can result in more severe side effects like extreme drowsiness, dry mouth, and low blood pressure.
Central nervous system (CNS) depressants slow down brain activity and should not be taken with muscle relaxants. Benzodiazepines, such as Ativan, Xanax, Klonopin, and Valium, can facilitate severe sedation, dizziness, and worsened mental health issues.
Opioids, including oxycodone, methadone, hydrocodone, and tramadol, produce sedative-like effects similar to that of Tizanidine. Combining opioids and muscle relaxers can result in excessive tiredness, slowed breathing, respiratory failure, and overdose.
Mixing alcohol and muscle relaxers like Tizanidine can cause extreme sedation and heightened side effects. Muscle relaxers can exacerbate the effects of alcohol, as they are both depressants. Combining CNS depressants increases the risk of extreme sleepiness, blurry vision, fainting, low blood pressure, liver damage, and overdose.
The Severe Side Effects and Health Risks of Tizanidine
Tizanidine is an FDA-approved muscle relaxant for managing muscle stiffness and spasticity, yet carries significant risks. Serious side effects and health consequences with muscle relaxers include low blood pressure and heart rate, liver damage, hallucinations, extreme drowsiness, and fatigue. Other adverse reactions with Tizanidine can lead to drug dependency, withdrawal symptoms, and overdose potential with specific drug interactions.
Extremely Low Blood Pressure and Heart Rate
Muscle relaxers can potentially cause low blood pressure (hypotension) and low heart rate (bradycardia), particularly with higher doses. Low blood pressure with Tizanidine can heighten the risk of dizziness, blurry vision, and fainting. These side effects can potentially result in accidents, falls, and injuries, which can be life-threatening for older adults.
Slow or irregular heartbeat is associated with Tizanidine overdose symptoms, while rapid heart rate is associated with withdrawal.
Liver Damage
Certain muscle relaxant medications, including Tizanidine, are metabolized extensively in the liver. Individuals with existing hepatic impairment or liver conditions require close monitoring when taking Tizanidine, as its use can lead to severe hepatotoxicity, acute liver failure, and death.
Chronic use of Tizanidine or in higher doses also receives periodic monitoring and liver function tests due to the risks of liver toxicity. Liver damage facilitates symptoms including yellowing skin (jaundice), dark urine, and persistent nausea.
Hallucinations
Patients taking Tizanidine may experience visual hallucinations or delusions. While this side effect is rare, it is possible. Visual hallucinations with muscle relaxants are when you see something that isn’t there, also known as medication-induced psychosis. Experiencing these side effects can lead to other consequences, including poor decision-making, increased risk of accidents, and risk-taking behaviors.
Extreme Drowsiness and Fatigue
One of the most reported side effects of muscle relaxants is chronic fatigue, weakness, and extreme drowsiness. Tizanidine suppresses nerve signals in the spinal cord, causing the muscles to relax and reducing pain.
High doses or long-term use of Tizanidine can exacerbate its side effects of tiredness and relaxation, resulting in severe fatigue. This can present complications for those taking muscle relaxers throughout the day, interfering with their ability to drive, operate machinery, or complete daily tasks.
Muscle Relaxer Dependency and Withdrawal Symptoms
Patients who have been taking muscle relaxers for more extended periods may develop a physical dependency on the substance. While it is a relatively safe prescription medication, users may severely rely on it whenever they experience pain symptoms. Some people may misuse muscle relaxers to help them fall asleep and stay asleep at night.
Even though muscle relaxants like Tizanidine are not classified as a controlled substance, long-term use can lead to dependency and withdrawal. Abruptly stopping use of Tizanidine after prolonged use can lead to withdrawal symptoms like:
- Fast or irregular heartbeat or pulse
- High blood pressure
- Muscle stiffness or tightness
- Chest pain
- Tremors and anxiety
- Vomiting
- Insomnia
- Rebound headaches
- Tachycardia
- Increased spasticity
If you’re considering stopping Tizanidine, consult your doctor before proceeding to avoid adverse withdrawal symptoms.
Risk of Overdose
Taking too much Tizanidine can cause severe sedation, respiratory depression, seizures, coma, and even death. When Tizanidine and other muscle relaxants are taken with alcohol, opioids, benzodiazepines, and other medications, it heightens the risk of overdose. Tizanidine overdose symptoms include:
- Hallucinations
- Extreme drowsiness
- Slowed heart rate
- Seizures
- Difficulty breathing
- Respiratory depression
- Coma
- Death
Tizanidine’s risks of dependency, withdrawal, and overdose potential should not be ignored. If you or a loved one is using Tizanidine, take the medication as prescribed, avoid mixing substances, and monitor for side effects. If adverse side effects or dependency issues develop, consult your doctor immediately.
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References:
- StatPearls, 2023. Tizanidine.
- Mayo Clinic, 2025. Tizanidine (oral route).
- GoodRx, 2024. 7 Tizanidine Interactions You Should Know About.
- Medical News Today, 2023. What to know about tizanidine.
- Cleveland Clinic, 2023. Muscle Relaxers.
- GoodRx, 2024. Dry mouth, Drowsiness, and Dizziness: 11 Tizanidine Side Effects You Should Know About.