Tizanidine 2mg Capsules
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
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 acting on the brain and spinal cord to reduce nerve signals that cause muscle stiffness.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication with or without food, but be consistent in how you take it each time. If you take it with food, always take it with food. If you take it on an empty stomach, always take it on an empty stomach.
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. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposing of your medication, consult your pharmacist. You may also want to check if there are 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 dose, skip the missed dose and resume your normal schedule. Do not take two doses at the same time or take extra doses. If you take this medication as needed, do not take it more frequently than directed by your doctor.
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication with or without food, but be consistent in how you take it each time. If you take it with food, always take it with food. If you take it on an empty stomach, always take it on an empty stomach.
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. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposing of your medication, consult your pharmacist. You may also want to check if there are 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 dose, skip the missed dose and resume your normal schedule. Do not take two doses at the same time or take extra doses. If you take this medication as needed, do not take it more frequently than directed by your doctor.
Lifestyle & Tips
- Avoid alcohol and other medications that cause drowsiness (e.g., sedatives, opioids, antihistamines) as this can worsen dizziness and sleepiness.
- Do not drive or operate heavy machinery until you know how this medication affects you, as it can cause drowsiness and dizziness.
- Take tizanidine capsules consistently with or without food, as taking them with food can significantly increase the amount of drug absorbed.
- Avoid sudden changes in position (e.g., standing up quickly) to reduce the risk of dizziness or fainting due to 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, anxiety). Your doctor will guide you on how to slowly reduce the dose.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial 2 mg once daily, titrated up to 2-4 mg every 6-8 hours as needed, not to exceed 36 mg/day.
Dose Range:
2 - 36 mg
Condition-Specific Dosing:
spasticity:
Initial 2 mg once daily, gradually increase by 2-4 mg at 1-4 day intervals. Max single dose 16 mg. Max daily dose 36 mg.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment 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 and monitor closely. Tizanidine is minimally dialyzable.
Hepatic Impairment:
Mild:
Use with caution; monitor LFTs and for adverse effects.
Moderate:
Use with caution; monitor LFTs and for adverse effects. Consider lower starting dose and slower titration.
Severe:
Contraindicated in patients with significant hepatic impairment (e.g., cirrhosis).
Pharmacology
Mechanism of Action
Tizanidine is an alpha-2 adrenergic agonist. It acts centrally by increasing presynaptic inhibition of motor neurons, likely by inhibiting the release of excitatory amino acids (e.g., glutamate and aspartate) from interneurons, thereby reducing spasticity.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 40% (capsules with food: ~30% increase in Cmax and AUC compared to fasting)
Tmax:
1-2 hours
FoodEffect:
Tizanidine capsules taken with food result in a significant increase in Cmax (approximately 30%) and AUC (approximately 30%) compared to the fasting state. This is different from tizanidine tablets, where food decreases Cmax and AUC. Therefore, tizanidine capsules should be taken consistently with or without food.
Distribution:
Vd:
2.4 L/kg
ProteinBinding:
Approximately 30%
CnssPenetration:
Yes
Elimination:
HalfLife:
Approximately 2.5 hours
Clearance:
Not available (systemic 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
Serious Side Effects: Seek Medical Attention Immediately
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical help right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of liver problems, including:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Signs of a urinary tract infection (UTI), such as:
+ Blood in the urine
+ Burning or pain when passing urine
+ Frequent or urgent need to urinate
+ Fever
+ Lower stomach pain
+ Pelvic pain
Severe dizziness or fainting
Confusion
Hallucinations (seeing or hearing things that are not there)
Mood changes
Changes in behavior
Slow heartbeat
Fever, chills, or sore throat
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only have mild ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms, contact your doctor or seek medical help:
Dry mouth
Dizziness
Drowsiness
Fatigue
* Weakness
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, contact your doctor for medical advice. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical help right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of liver problems, including:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Signs of a urinary tract infection (UTI), such as:
+ Blood in the urine
+ Burning or pain when passing urine
+ Frequent or urgent need to urinate
+ Fever
+ Lower stomach pain
+ Pelvic pain
Severe dizziness or fainting
Confusion
Hallucinations (seeing or hearing things that are not there)
Mood changes
Changes in behavior
Slow heartbeat
Fever, chills, or sore throat
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only have mild ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms, contact your doctor or seek medical help:
Dry mouth
Dizziness
Drowsiness
Fatigue
* Weakness
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, contact your doctor for medical advice. 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:
- Signs of liver problems: unusual tiredness, nausea, vomiting, dark urine, yellowing of skin or eyes (jaundice), abdominal pain.
- Signs of severe low blood pressure: severe dizziness, lightheadedness, fainting.
- Signs of allergic reaction: rash, itching, swelling (especially of face/tongue/throat), severe dizziness, trouble breathing.
- Worsening muscle weakness or spasticity.
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, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction and its symptoms.
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 the safety of taking this medication with your existing treatments and health conditions. Never start, stop, or adjust the dose 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, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction and its symptoms.
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 the safety of taking this medication with your existing treatments and health conditions. Never start, stop, or adjust the dose 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.
When starting this medication, avoid driving and other activities that require alertness until you understand how it affects you. To minimize the risk of dizziness or fainting, get up slowly from a sitting or lying position, and be cautious when climbing stairs.
Before consuming alcohol, marijuana, or other forms of cannabis, or taking prescription or over-the-counter medications that may cause drowsiness, 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 discussing it with your doctor, as this may increase your risk of side effects. If you need to discontinue this medication, your doctor will instruct you on how to gradually stop taking it to minimize potential side effects.
Follow your doctor's instructions for regular blood tests 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 your medication from one form to another (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 changes in how it works or any side effects.
Animal studies have shown that this medication can cause fertility problems, but it is not known if it has the same effect in humans. Discuss this potential risk with your doctor.
If you are 65 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.
When starting this medication, avoid driving and other activities that require alertness until you understand how it affects you. To minimize the risk of dizziness or fainting, get up slowly from a sitting or lying position, and be cautious when climbing stairs.
Before consuming alcohol, marijuana, or other forms of cannabis, or taking prescription or over-the-counter medications that may cause drowsiness, 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 discussing it with your doctor, as this may increase your risk of side effects. If you need to discontinue this medication, your doctor will instruct you on how to gradually stop taking it to minimize potential side effects.
Follow your doctor's instructions for regular blood tests 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 your medication from one form to another (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 changes in how it works or any side effects.
Animal studies have shown that this medication can cause fertility problems, but it is not known if it has the same effect in humans. Discuss this potential risk with your doctor.
If you are 65 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:
- Drowsiness
- Dizziness
- Lightheadedness
- Bradycardia (slow heart rate)
- Hypotension (low blood pressure)
- Respiratory depression (slow, shallow breathing)
- Coma
What to Do:
Call 1-800-222-1222 (Poison Control Center) immediately or seek emergency medical attention. Treatment is supportive, including gastric lavage, activated charcoal, and maintaining vital signs.
Drug Interactions
Contraindicated Interactions
- Strong CYP1A2 inhibitors (e.g., fluvoxamine, ciprofloxacin)
- Moderate CYP1A2 inhibitors (e.g., zileuton, mexiletine, oral contraceptives, acyclovir, ticagrelor, propafenone, verapamil)
Major Interactions
- Other CNS depressants (e.g., alcohol, benzodiazepines, opioids, tricyclic antidepressants, sedating antihistamines) - increased sedation and hypotension
- Antihypertensives (e.g., ACE inhibitors, beta-blockers, diuretics) - increased risk of hypotension and bradycardia
- Alpha-2 adrenergic agonists (e.g., clonidine) - additive hypotensive effects
Moderate Interactions
- Oral contraceptives - may increase tizanidine exposure
- Acyclovir - may increase tizanidine exposure
- Zileuton - may increase tizanidine exposure
- Mexiletine - may increase tizanidine exposure
Monitoring
Baseline Monitoring
Liver function tests (ALT, AST)
Rationale: To establish baseline and identify pre-existing hepatic impairment, as tizanidine can cause hepatotoxicity.
Timing: Prior to initiation of therapy.
Blood pressure
Rationale: To establish baseline and assess risk of hypotension.
Timing: Prior to initiation of therapy.
Routine Monitoring
Liver function tests (ALT, AST)
Frequency: At 1, 3, and 6 months after initiation, 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
Frequency: Periodically, especially during dose titration and if symptoms of hypotension occur.
Target: Within patient's normal range, without symptomatic hypotension
Action Threshold: If symptomatic hypotension or significant drop in BP occurs, consider dose reduction or discontinuation.
Heart rate
Frequency: Periodically, especially during dose titration.
Target: Within normal limits
Action Threshold: If significant bradycardia occurs, consider dose reduction or discontinuation.
Sedation/Drowsiness
Frequency: Regularly assess patient's level of alertness.
Target: Acceptable level of alertness for daily activities
Action Threshold: If excessive sedation or impaired daily function, consider dose reduction.
Symptom Monitoring
- Dizziness
- Drowsiness
- Dry mouth
- Hypotension (lightheadedness, fainting)
- Bradycardia
- Weakness
- Fatigue
- Nausea
- Abdominal pain
- Dark urine
- Yellowing of skin/eyes (jaundice)
- Unusual tiredness
Special Patient Groups
Pregnancy
Category C. Animal studies show adverse effects on the fetus, but there are no adequate and well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus.
Trimester-Specific Risks:
First Trimester:
Potential for developmental toxicity observed in animal studies.
Second Trimester:
Potential for developmental toxicity observed in animal studies.
Third Trimester:
Potential for developmental toxicity observed in animal studies; risk of withdrawal symptoms in neonate if used near term.
Lactation
L3 (Moderately Safe). Tizanidine is excreted in human milk. Due to the potential for serious adverse reactions in breastfed infants (e.g., sedation, hypotonia, bradycardia), 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:
Sedation, hypotonia, bradycardia, and other CNS depression symptoms. Monitor infant closely.
Pediatric Use
Safety and effectiveness have not been established in pediatric patients. Not recommended for use in children.
Geriatric Use
Use with caution. Elderly patients may be more sensitive to the hypotensive and sedative effects of tizanidine. Consider lower starting doses and slower titration. Monitor blood pressure and CNS effects closely.
Clinical Information
Clinical Pearls
- Tizanidine capsules and tablets are NOT bioequivalent and cannot be interchanged on a milligram-for-milligram basis without dose adjustment. Capsules have different food effects than tablets.
- Always titrate the dose slowly to minimize adverse effects, especially hypotension and sedation.
- Abrupt discontinuation, especially after prolonged use or high doses, can lead to rebound hypertension, tachycardia, and hypertonia. Taper dose gradually.
- Monitor liver function tests (LFTs) at baseline, 1, 3, and 6 months, and periodically thereafter, or if symptoms of liver injury occur.
- Educate patients about the risk of dizziness, drowsiness, and hypotension, and advise them to avoid activities requiring mental alertness until they know how the drug affects them.
- Avoid concomitant use with strong or moderate CYP1A2 inhibitors due to significantly increased tizanidine levels and risk of adverse effects.
Alternative Therapies
- Baclofen
- Diazepam
- Dantrolene
- Gabapentin (off-label for spasticity)
- Botulinum toxin injections (for focal spasticity)
Cost & Coverage
Average Cost:
Varies widely, typically $10-$50 per 30 capsules (2mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.