SIRDALUD

Sirdalud 2 mg and Sirdalud 4 mg are prescription medicines containing tizanidine as tizanidine hydrochloride. Tizanidine is a centrally acting skeletal-muscle relaxant that acts mainly at spinal-cord level and reduces abnormally increased muscle tone, painful spasms and spasticity.

The dose must be individually adjusted because tizanidine has a narrow therapeutic index and blood concentrations may vary considerably between patients receiving the same dose.

Sirdalud – uses, dosage and important warnings

What is Sirdalud used for?

Sirdalud is used to treat painful involuntary muscle contractions or spasms associated with static and functional disorders of the spine, including:

• painful muscle spasms and tension in the lower back;
• lumbar syndromes;
• neck pain and stiffness;
• cervical syndromes.

It is also used to reduce spasticity and increased muscle tone caused by neurological conditions such as:

• multiple sclerosis;
• degenerative diseases of the spine;
• cerebrovascular disease;
• cerebral palsy.

Sirdalud reduces muscle tone and spasms but does not treat the underlying neurological disease, injury or spinal condition.

How is Sirdalud taken?

Take the medicine exactly as prescribed. It may be taken with or without food and should be swallowed with sufficient water.

Because drowsiness, low blood pressure and other adverse effects may occur, treatment is generally started with a low dose and adjusted carefully.

Dosage for painful muscle spasms

The usual dose is:

• 2 mg or 4 mg three times daily;
• in more severe cases, the doctor may prescribe an additional 2 mg or 4 mg dose at bedtime.

A lower starting dose of 2 mg three times daily may reduce the risk of adverse effects. The strength, number of daily doses and treatment duration are determined by the doctor.

Dosage for neurological spasticity

• The initial daily dose should not exceed 6 mg divided into three separate doses.
• The dose may be increased by 2 mg or 4 mg at intervals of three to seven days.
• An optimal response is often achieved with 12–24 mg daily, divided into three or four doses.
• The maximum daily dose is 36 mg and must not be exceeded.

These doses are not instructions for self-adjustment. Every dose change must be supervised by a doctor.

Kidney impairment

For patients with creatinine clearance below 25 mL/min, the recommended starting dose is generally 2 mg once daily.

The dose is increased gradually according to tolerability and response. Exposure to tizanidine may be substantially increased in kidney impairment.

Older patients

Treatment in older patients should begin with the lowest dose and be increased cautiously. Reduced kidney clearance may increase exposure to tizanidine and the risk of adverse effects.

Who must not take Sirdalud?

• people allergic to tizanidine or another ingredient;
• patients with severe liver impairment;
• patients taking ciprofloxacin;
• patients taking fluvoxamine.

Ciprofloxacin and fluvoxamine may substantially increase tizanidine exposure and cause prolonged, clinically significant low blood pressure, drowsiness, dizziness, reduced psychomotor performance and heart-rhythm abnormalities.

Low blood pressure and slow heart rate

Sirdalud may cause hypotension. The risk is greater when treatment begins, after a dose increase and when other blood-pressure-lowering medicines are used.

Possible symptoms include:

• dizziness or light-headedness;
• cold sweating and marked weakness;
• unsteadiness when standing;
• blurred vision;
• a slow heart rate;
• fainting or circulatory collapse.

Stand up slowly from a bed or chair. Loss of consciousness, severe weakness, a very slow pulse or breathing difficulty requires urgent medical assessment.

Liver-function monitoring

Tizanidine may cause abnormal liver function, hepatitis or, very rarely, liver failure.

Patients receiving 12 mg or more daily should generally have liver-function tests once monthly during the first four months. Testing is also required if symptoms develop, including:

• unexplained nausea;
• loss of appetite;
• marked tiredness or weakness;
• dark urine;
• pale stools;
• yellowing of the skin or eyes;
• pain in the upper-right abdomen.

Interactions with other medicines

Tell the doctor and pharmacist about all medicines being used.

Sirdalud must not be taken with:

• ciprofloxacin;
• fluvoxamine.

Concurrent use is not recommended or requires particular caution with:

• amiodarone, mexiletine and propafenone;
• cimetidine;
• certain fluoroquinolone antibiotics, including enoxacin, pefloxacin and norfloxacin;
• oral contraceptives;
• ticlopidine;
• medicines that prolong the QT interval, including certain antiarrhythmics, amitriptyline and azithromycin;
• antihypertensive medicines and diuretics;
• clonidine and other alpha-2 adrenergic agonists;
• benzodiazepines, sleeping medicines and sedatives;
• strong analgesics;
• sedating antihistamines;
• baclofen;
• rifampicin.

Rifampicin and tobacco smoke may reduce tizanidine exposure and weaken its effect. A major change in smoking habits should be reported to the doctor because it may change the response to the prescribed dose.

Alcohol and Sirdalud

Alcohol should be avoided or kept to a minimum because it may increase:

• drowsiness and sedation;
• dizziness;
• low blood pressure;
• psychomotor impairment;
• the risk of falls and injuries.

Stopping treatment

Sirdalud must not be stopped suddenly following prolonged treatment or high-dose use, particularly in patients also receiving antihypertensive medicines.

Sudden discontinuation may cause:

• marked rebound hypertension;
• headache and dizziness;
• a rapid heartbeat;
• in extreme cases, a cerebrovascular event.

The doctor will gradually reduce the dose when treatment needs to be discontinued.

Pregnancy, breastfeeding and contraception

Sirdalud is not recommended during pregnancy unless the doctor determines that the expected benefit clearly outweighs the possible risk.

Sexually active women who may become pregnant are advised to have a pregnancy test before treatment and to use effective contraception during treatment and for at least one day after the final dose.

Sirdalud should not be used while breastfeeding because adequate human safety information is unavailable.

Driving and using machines

Sirdalud may cause drowsiness, dizziness, blurred vision, muscle weakness and low blood pressure.

Do not drive, use tools or operate machinery if any of these effects occurs. A patient’s individual response cannot be reliably predicted at the start of treatment.

Possible side effects

Very common adverse effects include:

• drowsiness;
• dizziness;
• tiredness and weakness;
• dry mouth;
• gastrointestinal disturbances;
• muscle weakness.

Common effects include low blood pressure, insomnia or other sleep disorders and a temporary increase in liver transaminases.

A slow heart rate may occur uncommonly. Nausea, fainting, blurred vision, vertigo, hallucinations, confusion, rash, itching, dermatitis, hives, hepatitis and liver failure have also been reported.

Overdose

Tizanidine overdose may cause:

• nausea and vomiting;
• markedly low blood pressure;
• QT-interval prolongation and abnormal heart rhythm;
• dizziness and profound drowsiness;
• constricted pupils;
• agitation;
• breathing disturbances;
• coma.

Contact a doctor or emergency medical service immediately if too much medicine has been taken and bring the original packaging.

Missed dose

Take a forgotten dose when remembered unless it is almost time for the next dose. Do not take a double dose.

Availability and price

Related muscle support

Products for massage, local care and nutritional support of normal muscle function are available in the Muscle Problems category.

Dietary supplements, magnesium products, gels and creams do not replace Sirdalud in neurological spasticity or painful spasms for which tizanidine has been prescribed. Patients with kidney disease, low blood pressure or regular medication should check any additional product with a doctor or pharmacist.

Related blog topic: Which is the safest painkiller? Sirdalud is a muscle relaxant rather than a conventional analgesic and must not be independently replaced with a painkiller.

Composition, appearance and packaging

Sirdalud 2 mg: each tablet contains 2 mg of tizanidine as tizanidine hydrochloride and 80 mg of anhydrous lactose.

The 2 mg tablet is white to almost white, round, flat and bevelled, with a score line between the markings “O” and “Z”. It may be divided into two equal doses.

Sirdalud 4 mg: each tablet contains 4 mg of tizanidine as tizanidine hydrochloride and 110 mg of anhydrous lactose.

The 4 mg tablet is white to almost white, round, flat and bevelled, with a cross-shaped score line on one side and “RL” on the other. Despite the cross-shaped score, it may be divided into two equal halves only.

Other ingredients are anhydrous colloidal silicon dioxide, stearic acid and microcrystalline cellulose.

Both packs contain three blisters of 10 tablets, providing 30 tablets in total.

Marketing authorisation holder: Sandoz Pharmaceuticals d.d. Representative Office, Belgrade.
Manufacturer: Novartis Sağlık, Gıda ve Tarım Ürünleri San. ve Tic. A.Ş., Istanbul, Türkiye.

Storage

Keep out of the sight and reach of children. Store below 25°C.

Do not use after the expiry date stated on the outer packaging and blister. Return unused medicine to a pharmacy that collects pharmaceutical waste.

Frequently asked questions

Official sources: ALIMS – Patient Information Leaflet | ALIMS – Summary of Product Characteristics.
Authorisation numbers: Sirdalud 2 mg – 000457798 2023; Sirdalud 4 mg – 000457207 2023. Both authorisations were renewed on 26 August 2024. The leaflet was last approved in August 2024. Content checked: July 2026.