Tizanidine 2mg Tablets
It is used to relax muscles.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Skeletal Muscle Relaxant
Pharmacologic Class
Alpha-2 Adrenergic Agonist
Pregnancy Category
Category C
FDA Approved
Dec 1996
DEA Schedule
Not Controlled
Overview
What is this medicine?
Tizanidine is a medication used to relax muscles and relieve muscle spasms, stiffness, and tightness caused by conditions like multiple sclerosis or spinal cord injury. It works by affecting nerves in the brain and spinal cord to reduce muscle overactivity.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. You can take this medication with or without food, but it's essential to take it the same way each time. Choose to take it either always with food or always on an empty stomach to maintain consistency.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a safe location, out of the reach of children and pets. When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so by your pharmacist. Instead, check with your pharmacist for guidance on the best disposal method or explore drug take-back programs in your area.
Missing a Dose
If you take this medication regularly and miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses. If you take this medication as needed, follow your doctor's instructions and do not take it more frequently than recommended.
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. You can take this medication with or without food, but it's essential to take it the same way each time. Choose to take it either always with food or always on an empty stomach to maintain consistency.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a safe location, out of the reach of children and pets. When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so by your pharmacist. Instead, check with your pharmacist for guidance on the best disposal method or explore drug take-back programs in your area.
Missing a Dose
If you take this medication regularly and miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses. If you take this medication as needed, follow your doctor's instructions and do not take it more frequently than recommended.
Lifestyle & Tips
- Avoid alcohol consumption while taking tizanidine, as it can increase drowsiness and dizziness.
- Avoid driving or operating heavy machinery until you know how tizanidine affects you, as it can cause drowsiness, dizziness, and low blood pressure.
- Do not stop taking tizanidine suddenly, especially if you have been on it for a long time or at high doses, as this can lead to withdrawal symptoms (e.g., rebound spasticity, high blood pressure, fast heart rate, tremor, anxiety). Your doctor will guide you on how to slowly reduce the dose.
- Take tizanidine consistently with or without food, but try to stick to the same way each time (e.g., always with food or always without food) to maintain consistent drug levels.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial 2 mg orally once daily, titrated up to 2-4 mg every 6-8 hours as needed, not to exceed 3 doses in 24 hours. Max single dose 16 mg. Max daily dose 36 mg.
Dose Range:
2 - 36 mg
Condition-Specific Dosing:
spasticity:
Initial 2 mg, increased by 2-4 mg increments at 1-4 day intervals based on response and tolerability. Usual therapeutic range 8-36 mg/day in 3-4 divided doses.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment needed for CrCl > 25 mL/min, but monitor for adverse effects.
Moderate:
For CrCl < 25 mL/min, reduce initial dose to 2 mg once daily. Titrate slowly based on response and tolerability.
Severe:
For CrCl < 25 mL/min, reduce initial dose to 2 mg once daily. Titrate slowly based on response and tolerability.
Dialysis:
Not well studied. Use with caution, monitor closely for adverse effects. Tizanidine is not significantly removed by hemodialysis.
Hepatic Impairment:
Mild:
Use with caution. Monitor liver function tests.
Moderate:
Use with caution. Monitor liver function tests. Consider lower doses and slower titration.
Severe:
Contraindicated in severe hepatic impairment. Use with extreme caution in any hepatic impairment due to risk of liver injury.
Pharmacology
Mechanism of Action
Tizanidine is an alpha-2 adrenergic agonist. It reduces spasticity by increasing presynaptic inhibition of motor neurons at the alpha-2 adrenergic receptors, primarily within the spinal cord. This leads to a reduction in the release of excitatory amino acids, thereby decreasing muscle tone and clonus.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 40%
Tmax:
1-2 hours
FoodEffect:
Food increases Cmax by approximately 30% and Tmax by 1 hour, but the extent of absorption (AUC) is not significantly affected. However, administration with food can reduce the rate of absorption, leading to lower peak concentrations and potentially less pronounced side effects.
Distribution:
Vd:
Approximately 2.4 L/kg
ProteinBinding:
Approximately 30%
CnssPenetration:
Yes
Elimination:
HalfLife:
Approximately 2.5 hours (range 1.5-4 hours)
Clearance:
Approximately 2.4 L/hr/kg
ExcretionRoute:
Renal (approximately 60% of dose), Fecal (approximately 20%)
Unchanged:
Approximately 5% (renal)
Pharmacodynamics
OnsetOfAction:
Within 1 hour
PeakEffect:
1-2 hours
DurationOfAction:
3-6 hours
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction: rash, hives, itching, red, swollen, blistered, or peeling skin (with or without fever), wheezing, tightness in the chest or throat, difficulty breathing, swallowing, or talking, unusual hoarseness, or swelling of the mouth, face, lips, tongue, or throat
Signs of liver problems: dark urine, fatigue, decreased appetite, upset stomach or stomach pain, light-colored stools, vomiting, or yellow skin or eyes
Signs of a urinary tract infection (UTI): blood in the urine, burning or pain when urinating, frequent or urgent need to urinate, fever, lower abdominal pain, or pelvic pain
Severe dizziness or fainting
Confusion
Hallucinations (seeing or hearing things that are not there)
Mood changes or changes in behavior
Slow heartbeat
Fever, chills, or sore throat
Other Possible Side Effects
Like all medications, this drug can cause side effects. Many people may not experience any side effects or only minor ones. If you notice any of the following side effects or any other unusual symptoms, contact your doctor for advice:
Dry mouth
* Dizziness, drowsiness, fatigue, or weakness
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction: rash, hives, itching, red, swollen, blistered, or peeling skin (with or without fever), wheezing, tightness in the chest or throat, difficulty breathing, swallowing, or talking, unusual hoarseness, or swelling of the mouth, face, lips, tongue, or throat
Signs of liver problems: dark urine, fatigue, decreased appetite, upset stomach or stomach pain, light-colored stools, vomiting, or yellow skin or eyes
Signs of a urinary tract infection (UTI): blood in the urine, burning or pain when urinating, frequent or urgent need to urinate, fever, lower abdominal pain, or pelvic pain
Severe dizziness or fainting
Confusion
Hallucinations (seeing or hearing things that are not there)
Mood changes or changes in behavior
Slow heartbeat
Fever, chills, or sore throat
Other Possible Side Effects
Like all medications, this drug can cause side effects. Many people may not experience any side effects or only minor ones. If you notice any of the following side effects or any other unusual symptoms, contact your doctor for advice:
Dry mouth
* Dizziness, drowsiness, fatigue, or weakness
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe dizziness or fainting (signs of low blood pressure)
- Slow heartbeat
- Excessive drowsiness or sedation
- Signs of liver problems: unusual tiredness, nausea, vomiting, abdominal pain, dark urine, yellowing of skin or eyes (jaundice)
- Allergic reaction: rash, itching, swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing
- Withdrawal symptoms if stopped suddenly: increased muscle spasms, high blood pressure, fast heart rate, tremor, anxiety, confusion, hallucinations
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, any of its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you are currently taking ciprofloxacin or fluvoxamine, as these medications may interact with this drug.
Please note that this is not an exhaustive list of all potential interactions. To ensure your safety, it is crucial to disclose all of your:
Prescription and over-the-counter (OTC) medications
Natural products
Vitamins
Health problems
Your doctor and pharmacist need this information to assess potential interactions and determine whether it is safe for you to take this medication with your existing regimen. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, any of its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you are currently taking ciprofloxacin or fluvoxamine, as these medications may interact with this drug.
Please note that this is not an exhaustive list of all potential interactions. To ensure your safety, it is crucial to disclose all of your:
Prescription and over-the-counter (OTC) medications
Natural products
Vitamins
Health problems
Your doctor and pharmacist need this information to assess potential interactions and determine whether it is safe for you to take this medication with your existing regimen. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
To ensure your safety, avoid driving and other activities that require alertness until you understand how this medication affects you. When getting up from a sitting or lying down position, rise slowly to minimize the risk of dizziness or fainting. Be cautious when climbing stairs.
Before consuming alcohol, marijuana, or other forms of cannabis, or taking prescription or over-the-counter medications that may impair your reactions, consult with your doctor.
If you have been taking a high dose of this medication or using it regularly, do not stop taking it abruptly without first consulting your doctor. Stopping the medication suddenly may increase your risk of side effects. If you need to discontinue use, your doctor will guide you on how to gradually stop taking it.
As directed by your doctor, have your blood work checked and discuss the results with them.
Do not switch between the capsule and tablet forms of this medication without consulting your doctor. If your doctor changes the form of the medication you are taking (e.g., from capsules to tablets), the new form may interact differently with food. Your doctor may monitor you closely after switching to the new form to check for any differences in how it works or potential side effects.
Animal studies have shown that this medication can cause fertility problems. Although it is unclear if this medication affects human fertility, discuss any concerns with your doctor.
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.
If you are pregnant, plan to become pregnant, or are breastfeeding, inform your doctor. You and your doctor will need to discuss the potential benefits and risks of this medication to you and your baby.
To ensure your safety, avoid driving and other activities that require alertness until you understand how this medication affects you. When getting up from a sitting or lying down position, rise slowly to minimize the risk of dizziness or fainting. Be cautious when climbing stairs.
Before consuming alcohol, marijuana, or other forms of cannabis, or taking prescription or over-the-counter medications that may impair your reactions, consult with your doctor.
If you have been taking a high dose of this medication or using it regularly, do not stop taking it abruptly without first consulting your doctor. Stopping the medication suddenly may increase your risk of side effects. If you need to discontinue use, your doctor will guide you on how to gradually stop taking it.
As directed by your doctor, have your blood work checked and discuss the results with them.
Do not switch between the capsule and tablet forms of this medication without consulting your doctor. If your doctor changes the form of the medication you are taking (e.g., from capsules to tablets), the new form may interact differently with food. Your doctor may monitor you closely after switching to the new form to check for any differences in how it works or potential side effects.
Animal studies have shown that this medication can cause fertility problems. Although it is unclear if this medication affects human fertility, discuss any concerns with your doctor.
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.
If you are pregnant, plan to become pregnant, or are breastfeeding, inform your doctor. You and your doctor will need to discuss the potential benefits and risks of this medication to you and your baby.
Overdose Information
Overdose Symptoms:
- Profound hypotension (very low blood pressure)
- Bradycardia (slow heart rate)
- Drowsiness
- Dizziness
- Somnolence (excessive sleepiness)
- Miosis (constricted pupils)
- Respiratory depression
- Coma
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Treatment is supportive, including maintaining airway, breathing, and circulation. Gastric lavage may be considered if performed soon after ingestion. Hemodialysis is not effective.
Drug Interactions
Contraindicated Interactions
- Fluvoxamine (potent CYP1A2 inhibitor)
- Ciprofloxacin (potent CYP1A2 inhibitor)
Major Interactions
- Other CYP1A2 inhibitors (e.g., zileuton, mexiletine, oral contraceptives, acyclovir, ticlopidine, verapamil, propafenone, amiodarone, enoxacin, pefloxacin, norfloxacin, rofecoxib, etoricoxib, famotidine, cimetidine): May significantly increase tizanidine levels, leading to hypotension, bradycardia, and excessive sedation.
- CNS depressants (e.g., alcohol, benzodiazepines, opioids, tricyclic antidepressants, antihistamines): Increased risk of sedation, drowsiness, and hypotension.
- Antihypertensives (e.g., diuretics, beta-blockers, ACE inhibitors, ARBs): Increased risk of hypotension and bradycardia.
Moderate Interactions
- Oral contraceptives: May increase tizanidine levels (moderate CYP1A2 inhibition).
- Alpha-1 adrenergic blockers (e.g., prazosin, terazosin): Increased risk of hypotension.
- Baclofen, cyclobenzaprine, carisoprodol, metaxalone, methocarbamol: Additive CNS depression.
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Liver Function Tests (ALT, AST)
Rationale: To establish baseline and identify pre-existing hepatic impairment, as tizanidine can cause liver injury.
Timing: Prior to initiation of therapy.
Blood Pressure (BP) and Heart Rate (HR)
Rationale: To establish baseline and monitor for hypotensive and bradycardic effects.
Timing: Prior to initiation of therapy.
Routine Monitoring
Liver Function Tests (ALT, AST)
Frequency: At 1, 3, and 6 months after initiation of therapy, and periodically thereafter, or if symptoms of liver injury occur.
Target: Within normal limits
Action Threshold: Discontinue if ALT or AST are persistently >3 times the upper limit of normal (ULN) or if accompanied by signs/symptoms of liver injury.
Blood Pressure (BP) and Heart Rate (HR)
Frequency: Periodically, especially during dose titration and if symptoms of hypotension or bradycardia occur.
Target: Maintain within patient's normal range, avoid symptomatic hypotension.
Action Threshold: If symptomatic hypotension or significant bradycardia occurs, reduce dose or discontinue.
Sedation/Drowsiness
Frequency: Regularly, especially during dose titration.
Target: Minimal to tolerable
Action Threshold: If excessive, reduce dose or discontinue.
Symptom Monitoring
- Dizziness
- Drowsiness
- Dry mouth
- Hypotension (lightheadedness, fainting)
- Bradycardia
- Weakness
- Fatigue
- Nausea
- Abdominal pain
- Dark urine
- Yellowing of skin/eyes (jaundice)
- Unusual tiredness
- Loss of appetite
Special Patient Groups
Pregnancy
Use during pregnancy only if the potential benefit justifies the potential risk to the fetus. Animal studies show adverse effects, but there are no adequate and well-controlled studies in pregnant women.
Trimester-Specific Risks:
First Trimester:
Potential for developmental toxicity observed in animal studies.
Second Trimester:
Not specifically studied, but systemic exposure could affect fetal development.
Third Trimester:
Not specifically studied, but potential for neonatal withdrawal or effects on muscle tone.
Lactation
It is not known whether tizanidine is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Infant Risk:
Risk cannot be excluded. Potential for sedation, hypotonia, and other CNS effects in the infant.
Pediatric Use
Safety and effectiveness in pediatric patients have not been established. Not recommended for use in children.
Geriatric Use
Use with caution in elderly patients due to increased sensitivity to adverse effects (e.g., hypotension, sedation, dry mouth, weakness). Start with lower doses and titrate slowly. Renal function should be monitored.
Clinical Information
Clinical Pearls
- Tizanidine is an alpha-2 adrenergic agonist, not a direct muscle relaxant like benzodiazepines. Its mechanism is central.
- Dose titration is crucial to minimize side effects, especially hypotension and sedation. Start low and go slow.
- Switching between tizanidine tablets and capsules can affect bioavailability; maintain consistency in formulation or re-titrate if switching.
- Avoid abrupt discontinuation due to the risk of rebound hypertension, tachycardia, and hypertonia.
- Liver function tests are important for monitoring, especially during the first 6 months of therapy.
- Concomitant use with potent CYP1A2 inhibitors (e.g., fluvoxamine, ciprofloxacin) is contraindicated due to significantly increased tizanidine levels and risk of severe hypotension and sedation.
Alternative Therapies
- Baclofen (GABA-B agonist)
- Diazepam (Benzodiazepine, GABA-A agonist)
- Dantrolene (Direct muscle relaxant)
- Cyclobenzaprine (Centrally acting muscle relaxant)
- Botulinum toxin injections (for localized spasticity)
Cost & Coverage
Average Cost:
Varies, typically $10-$50 per 30 tablets
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe and effective treatment, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it is a good idea to consult with your pharmacist. If you have any questions or concerns about this medication, do not hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide detailed information about the overdose, including the medication taken, the amount, and the time it occurred.