4 mg muscle relaxer. Tizanidine: Complete Dosage Guide, Max Dose, and Adjustments for Muscle Relaxation

02.09.202313.06.2023 by alexxlab

What is the recommended dosage for tizanidine. How should the dose be adjusted for renal impairment. What is the maximum daily dose of tizanidine. How does food affect tizanidine absorption. What precautions should be taken when using tizanidine.

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Understanding Tizanidine: A Powerful Muscle Relaxant

Tizanidine, commonly known by its brand name Zanaflex, is a short-acting muscle relaxant used to manage spasticity associated with conditions like multiple sclerosis and spinal cord injuries. It works by blocking nerve impulses that send pain sensations to the brain, thereby temporarily relaxing muscles and reducing muscle spasms.

How Does Tizanidine Work?

Tizanidine acts as a central alpha-2 adrenergic agonist, which means it stimulates certain receptors in the central nervous system. This action results in a reduction of muscle tone and spasticity, providing relief for patients suffering from various neuromuscular disorders.

Tizanidine Dosage Guidelines for Adults

The appropriate dosage of tizanidine can vary depending on individual patient factors and the severity of muscle spasms. Here are the general guidelines for adult dosing:

Initial dose: 2 mg orally every 6 to 8 hours as needed
Peak effects occur in approximately 1 to 2 hours
Effects last for 3 to 6 hours
Treatment can be repeated up to a maximum of 3 doses in 24 hours
Dose can be gradually increased by 2 to 4 mg at intervals of 1 to 4 days

Maximum Dosage Limits

To ensure patient safety, there are strict limits on the maximum dosage of tizanidine:

Maximum single dose: 16 mg
Maximum daily dose: 36 mg in 24 hours

Dosage Adjustments for Special Populations

Certain patient groups may require dosage adjustments to ensure safe and effective use of tizanidine.

Renal Impairment Dosing

For patients with severe renal impairment (creatinine clearance less than 25 mL/min):

Individualize therapy with lower doses during dose titration
If higher doses are required, increase individual doses rather than dosing frequency
Closely monitor for toxicity

Liver Impairment Considerations

Tizanidine is not recommended for patients with liver impairment. The drug is primarily metabolized in the liver, and impaired hepatic function can lead to increased drug concentrations and potential toxicity.

The Impact of Food on Tizanidine Absorption

The absorption of tizanidine can be significantly affected by food intake. Clinically significant differences in absorption are expected between capsules and tablets when taken with or without food. These differences could result in changes in efficacy and tolerability.

Consistent Administration Regimen

Once a decision is made regarding formulation (capsule or tablet) and whether to take it with or without food, this regimen should not be altered. Consistency in administration helps maintain predictable drug levels and effects.

Precautions and Monitoring During Tizanidine Therapy

To ensure safe and effective use of tizanidine, several precautions and monitoring strategies should be implemented:

Obtain baseline aminotransferase levels and monitor at 1 month after reaching maximum dose
Consider obtaining baseline renal function in elderly patients
Monitor for hypotension, especially in at-risk patients and those on antihypertensive therapy
Watch for sedation in patients receiving concomitant CNS depressant agents

Special Considerations for Elderly Patients

Tizanidine should be used with caution in elderly patients, especially those with renal impairment. Lower initial doses and slower titration may be necessary to minimize adverse effects.

Discontinuation and Withdrawal of Tizanidine

Abrupt discontinuation of tizanidine, especially after prolonged use, can lead to withdrawal symptoms and rebound effects. To minimize these risks, a gradual dose reduction is recommended:

Decrease dose by 2 to 4 mg per day
This is particularly important for patients who have been receiving doses of 20 to 36 mg per day for periods of 9 weeks or more

Potential Withdrawal Symptoms

Patients should be monitored for signs of withdrawal, which may include:

Rebound hypertension
Tachycardia
Hypertonia (increased muscle tone)

Patient Education and Counseling Points

Proper patient education is crucial for the safe and effective use of tizanidine. Healthcare providers should discuss the following points with patients:

Consistency in taking the medication with or without food
The importance of not altering the dosing regimen without consulting a healthcare provider
Potential interactions with other medications
The need to avoid abrupt discontinuation of the drug
Awareness of potential hypotension and the need for caution when changing positions
The sedative effects of tizanidine, especially when combined with other CNS depressants or alcohol

Reporting Side Effects

Patients should be encouraged to report any unusual or severe side effects to their healthcare provider promptly. This can help in early detection and management of potential complications.

Tizanidine Interactions and Contraindications

Tizanidine can interact with various medications, potentially leading to increased side effects or reduced efficacy. Some notable interactions include:

CYP1A2 inhibitors (e.g., fluvoxamine, ciprofloxacin) – can significantly increase tizanidine blood levels
Alpha-2 adrenergic agonists (e.g., clonidine) – may enhance hypotensive effects
CNS depressants (e.g., alcohol, benzodiazepines) – can increase sedation

Contraindications

Tizanidine is contraindicated in patients with:

Known hypersensitivity to tizanidine or its components
Concomitant use of fluvoxamine or other potent CYP1A2 inhibitors
Severe hepatic impairment

Healthcare providers should carefully review a patient’s medication list and medical history before prescribing tizanidine to avoid potential drug interactions and contraindications.

Monitoring Efficacy and Adjusting Treatment

The effectiveness of tizanidine treatment should be regularly assessed to ensure optimal patient outcomes. Factors to consider include:

Reduction in muscle tone and spasticity
Improvement in activities of daily living
Patient-reported pain and discomfort levels
Occurrence and severity of side effects

Treatment Adjustments

Based on the patient’s response and tolerability, the tizanidine regimen may need to be adjusted. This could involve:

Dose titration (increasing or decreasing the dose)
Changing the dosing frequency
Exploring combination therapy with other muscle relaxants or pain medications
Considering alternative treatments if tizanidine is ineffective or poorly tolerated

Regular follow-up appointments and open communication between the patient and healthcare provider are essential for optimizing tizanidine therapy and managing any potential issues that may arise during treatment.

Tizanidine Dosage Guide + Max Dose, Adjustments

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Medically reviewed by Drugs.com. Last updated on Feb 27, 2023.

Applies to the following strengths: 4 mg; 2 mg; 6 mg

Usual Adult Dose for:

Muscle Spasm

Additional dosage information:

Renal Dose Adjustments
Liver Dose Adjustments
Dose Adjustments
Precautions
Dialysis
Other Comments

Usual Adult Dose for Muscle Spasm

Initial dose: 2 mg orally every 6 to 8 hours as needed

Peak effects occur in approximately 1 to 2 hours and last for 3 to 6 hours; treatment can be repeated as needed to a maximum of 3 doses in 24 hours; gradually increase dose by 2 to 4 mg at intervals of 1 to 4 days until satisfactory reduction of muscle tone is achieved.

Maximum single dose: 16 mg
Maximum daily dose: 36 mg in 24 hours

Comments:

Clinically significant differences in absorption are expected between capsules and tablets when taken with or without food; these differences could result in changes in efficacy and tolerability.
Once a formulation is decided on and a decision is made to take with or without food, this regimen should not be altered.

Use: Management of spasticity.

Renal Dose Adjustments

Severe renal impairment (CrCl less than 25 mL/min): Individualize therapy with lower doses during dose titration; if higher doses are required, individual doses should be increased rather increasing the dosing frequency; closely monitor for toxicity

Liver Dose Adjustments

Not recommended

Dose Adjustments

Use with caution in elderly patients, especially those with renal impairment.

Drug withdrawal:

Decrease by 2 to 4 mg per day, especially in patients who have been receiving doses of 20 to 36 mg per day for periods of 9 weeks or more.

Precautions

Safety and efficacy have not been established in patients younger than 18 years.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available

Other Comments

Administration advice:

May take orally with or without food; however, once a formulation is decided on and a decision is made to take with or without food, this regimen should not be altered.

General:

Because this drug has a relatively short duration of effect, dosing should occur at times when relief of spasticity is most important, such as before activities of daily living.
Considerable variation in response has been observed and therefore careful titration is necessary in order to not exceed the dose producing the desired effect.
Gradual dose reduction is advised on discontinuation so as to minimize risk of withdrawal and rebound hypertension, tachycardia, and hypertonia.

Monitoring:

Obtain aminotransferase levels at baseline, 1 month after maximum dose is achieved, and as clinically indicated (e.g. if hepatic injury is suspected).
Consider obtaining baseline renal function in elderly patients.
Monitor for hypotension in at-risk patients and those receiving concomitant antihypertensive therapy.
Monitor for sedation in patients receiving concomitant CNS depressant agents.

Patient advice:

Patients may take this drug with or without food, but once the decision is made to take with or without food it should be taken this way consistently.
Patients should check with their healthcare provider before starting or stopping any medications as this drug is known to interact with other medications.
Patients should be advised not to abruptly stop taking this medication without first talking with their healthcare provider.
Patients should be advised that this drug may cause hypotension and they should be careful when changing positions form lying to standing.
Patients should be advised this drug may cause significant somnolence, especially if taken with other CNS depressants or alcohol; they should refrain from activities requiring mental alertness until the effects of the drug are known.

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Medical Disclaimer

Zanaflex: Uses, Dosage & Side Effects

Generic name: tizanidine [ tye-ZAN-i-deen ]
Drug class: Skeletal muscle relaxants

Medically reviewed by Kaci Durbin, MD. Last updated on Mar 29, 2023.

What is Zanaflex?

Zanaflex is a short-acting muscle relaxer. It works by blocking nerve impulses (pain sensations) that are sent to your brain.

Zanaflex is used to treat spasticity associated with diseases like multiple sclerosis and spinal cord injuries by temporarily relaxing muscle tone.

Zanaflex may also be used for purposes not listed in this medication guide.

Warnings

Zanaflex is a short-acting medication that should be taken only for daily activities that require relief from muscle spasticity.

You should not take tizanidine if you are also taking fluvoxamine (Luvox) or ciprofloxacin (Cipro).

Do not use Zanaflex at a time when you need muscle tone for safe balance and movement during certain activities. In some situations, it may endanger your physical safety to be in a state of reduced muscle tone.

Switching between Zanaflex tablets and capsules, or changing the way you take it with regard to eating, can cause an increase in side effects or a decrease in therapeutic effect. Follow your doctor’s instructions carefully. After making any changes in how you take Zanaflex, contact your doctor if you notice any change in how well the medicine works or if it causes increased side effects.

Do not take more than three doses (36 mg) of tizanidine in a 24-hour period. Too much of tizanidine can damage your liver. Cold or allergy medicine, narcotic pain medicine, sleeping pills, other muscle relaxers, and medicine for seizures, depression or anxiety can add to sleepiness caused by tizanidine. Tell your doctor if you need to use any of these other medicines together with Zanaflex.

Avoid drinking alcohol. It can increase some of the side effects of tizanidine.

Before taking this medicine

You should not use Zanaflex if you are allergic to tizanidine, or if:

To make sure Zanaflex is safe for you, tell your doctor if you have ever had:

It is not known whether Zanaflex will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It may not be safe to breastfeed while using tizanidine. Ask your doctor about any risk.

How should I take Zanaflex?

Take Zanaflex exactly as it was prescribed for you. Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Zanaflex is usually taken up to 3 times in one day. Allow 6 to 8 hours to pass between doses. Do not take more than three doses (36 mg) in a 24-hour period. Too much of this medicine can damage your liver.

You may take Zanaflex with or without food, but take it the same way each time. Switching between taking tizanidine with food and taking it without food can make the medicine less effective or cause increased side effects.

Switching between Zanaflex tablets and capsules may cause changes in side effects or how well the medicine works.

If you make any changes in how you take Zanaflex, tell your doctor if you notice any change in side effects or in how well the medicine works.

Zanaflex is a short-acting medication, and its effects will be most noticeable between 1 and 3 hours after you take it. You should take this medicine only for daily activities that require relief from muscle spasms.

You will need frequent blood tests to check your liver function.

If you stop using Zanaflex suddenly after long-term use, you may have withdrawal symptoms such as dizziness, fast heartbeats, tremors, and anxiety. Ask your doctor how to safely stop using this medicine.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include weakness, drowsiness, confusion, slow heart rate, shallow breathing, feeling light-headed, or fainting.

What to avoid

Do not use Zanaflex at a time when you need muscle tone for safe balance and movement during certain activities. In some situations, it may be dangerous for you to have reduced muscle tone.

Drinking alcohol with this medicine can cause side effects.

Avoid driving or hazardous activity until you know how Zanaflex will affect you. Your reactions could be impaired. Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.

Zanaflex side effects

Get emergency medical help if you have signs of an allergic reaction to Zanaflex: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

a light-headed feeling, like you might pass out;
weak or shallow breathing;
confusion, hallucinations; or
yellowing of the eyes or skin.
pain or burning when you urinate.

Common Zanaflex side effects may include:

drowsiness, dizziness, weakness;
dry mouth;
feeling nervous;
blurred vision;
flu-like symptoms;
abnormal liver function tests;
runny nose, sore throat;
urination problems, painful urination;
vomiting, constipation; or
uncontrolled muscle movements.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Dosing information

Usual Adult Dose for Muscle Spasm:

-Initial dose: 2 mg orally every 6 to 8 hours as needed
-The dose of Zanaflex can be increased by your doctor if needed
-The medication effects peak in about 1 to 2 hours and last for 3 to 6 hours
-Do not take more than 16mg of Zanaflex at one time. Do not take more than 36mg in 24 hours.

Comments:
-The capsules and tablets are absorbed differently by the body. Do not switch from one to the other without talking to your doctor.
-Zanaflex should be taken with food every time or without food every time. Do not switch back and forth.

What other drugs will affect Zanaflex?

Taking Zanaflex with other drugs that make you sleepy or slow your breathing can cause dangerous side effects or death. Ask your doctor before using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety or seizures.

Tell your doctor about all your other medicines, especially:

acyclovir;
ticlopidine;
zileuton;
birth control pills;
an antibiotic, including ciprofloxacin, levofloxacin, moxifloxacin, ofloxacin, or others;
blood pressure medicine such as clonidine, guanfacine, methyldopa;
heart rhythm medicine including amiodarone, mexiletine, propafenone, verapamil; or
stomach acid medicine such as cimetidine, famotidine.

This list is not complete. Other drugs may interact with tizanidine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Popular FAQ

The maximum effect of tizanidine occurs about 1 hour to 2 hours after taking a dose. It wears off in about 3 to 6 hours after taking it. Tizanidine is typically given no more than 3 times a day.

Tizanidine is not listed as a controlled substance by the U.S. Drug Enforcement Administration (DEA). Abuse potential has not been evaluated in human studies.

Tizanidine can cause sleepiness, but it has not been approved by the U.S. Food and Drug Administration (FDA) to treat sleep disorders. Tizanidine is a skeletal muscle relaxant. It is approved by the FDA to help relieve muscle spasms.

Tizanidine is known to cause low blood pressure. In some cases, it may cause low blood pressure that is so low that you could faint or pass out. The chances of fainting can be lowered if your doctor raises the dose of tizanidine very slowly. You may also have to be careful when you move from a sitting position to a standing position. In clinical trials, the most common side effects of tizanidine were dry mouth, sleepiness, dizziness and asthenia (defined as weakness, fatigue and/or tiredness).

Tizanidine normally starts working 1 to 2 hours after taking it. It wears off about 3 hours to 6 hours after taking it. Tizanidine can be taken up to 3 times a day to help relieve muscle spasms.

Tizanidine may be addictive, but it has not been evaluated in human studies. Withdrawal symptoms have been reported after abruptly stopping tizanidine, but abuse of other medications concomitantly was suspected in these cases. Dosing should be tapered off to avoid possible withdrawal symptoms.

Tizanidine is not known to cause weight gain. In clinical trials, the most common side effects of tizanidine were dry mouth, sleepiness, dizziness and asthenia (defined as weakness, fatigue and/or tiredness).