Pirdan

Properties

Pirdan contains Tizanidine, a centrally acting skeletal muscle relaxant, alpha-2-adrenergic receptor agonist, indicated for the management of spasticity. Tizanidine reduces spasticity by increasing presynaptic inhibition of motor neurons, and its effects are greater in polysynaptic pathways. The global effect of these actions is believed to reduce the facilitation of spinal motor neurons.

Pharmacokinetics

Absorption, distribution, metabolism and excretion

After oral administration, Tizanidine is fully absorbed, its oral bioavailability is approximately 40% due to extensive first pass hepatic metabolism (95%). The main isoenzyme of cytochrome P450 involved in its metabolism is CYP1A2. Tizanidine is widely distributed throughout the body bound to plasma proteins by approximately 30% and has a half-life of 2.5 hours. It is unknown if its metabolites are active. It is substantially excreted by the kidney (60%) and 20% in the faeces.

Therapeutic indications

Pirdan 2 and Pirdan 4 are indicated for the treatment of painful muscle spasms associated with spastic and functional disorders of the spine, such as cervical and lumbar syndromes.

Treatment of painful muscle spasms after surgery, either due to herniated intervertebral disc or osteoarthritis of the hip.

Treatment of spasticity due to neurological disorders, such as: multiple sclerosis, chronic myelopathy, degenerative diseases of the spinal cord, strokes and cerebral palsy.


Side effects

At the recommended therapeutic doses to treat painful muscle spasms, undesirable effects are generally mild and transient, including: drowsiness, fatigue, dizziness, dry mouth, nausea, gastrointestinal disorders, transient increase in serum transaminases, and slight reduction in blood pressure. At higher doses, the effects mentioned above appear with greater frequency and intensity, in addition to muscle weakness, insomnia, hallucinations and bradycardia.

Contraindications

Hypersensitivity to Tizanidine or to any component of the formula, significant liver function disorder and patients taking potent CYP1A2 inhibitors, such as fluvoxamine or ciprofloxacin.

Cautions

The use of Pirdan in combination with other alpha-2-adrenergic agonists is not recommended. Hypotension should be monitored when using tizanidine in patients receiving antihypertensive therapy, liver function tests should be performed in patients with doses of 12mg or more. Caution when driving vehicles or operating machinery, due to the sedative effect.

Special populations

Hepatic Impairment: the use of Pirdan is not recommended in this patient population, because liver impairment significantly affects its pharmacokinetics.

Renal Insufficiency: Pirdan should be used with caution in this patient population, since clearance is reduced by more than 50%, causing a longer duration of clinical effect.

Pregnancy and lactation

Tizanidine has not been studied in pregnant women, in which it should be used only if the benefit outweighs the risk to the fetus.

It is not known whether Tizanidine is excreted in human milk; therefore caution should be exercised when used in women who are breastfeeding.

Pediatric use

Safety and efficacy in pediatric patients have not been established.

Geriatric use

Because the elderly are more likely to have decreased kidney function, care should be taken in dose selection in this population.

Drug interactions

Antihypertensives including diuretics, alcohol, sedatives. Strong CYP1A2 inhibitors such as zileuton, fluoroquinolones, antiarrhythmics (amiodarone, mexiletine, propafenone), cimetidine, famotidine, oral contraceptives, acyclovir, and ticlopidine.

Warnings

Sale under prescription. Keep out of reach of children.

Composition

Pirdan 2

Each coated tablet contains:

Tizanidine (as tizanidine hydrochloride)    2 mg

C.S.P. excipients    1 comprimido

Pirdan 4

Each coated tablet contains:

Tizanidine (as tizanidine hydrochloride)    4 mg

C.S.P. excipients    1 comprimido


Administration route

Oral, with or without food.


Posology

 

The recommended starting dose is 2mg to 4mg, up to a maximum of three doses in 24 hours. In severe cases it can be gradually increased from 2mg to 4mg with each dose, until a satisfactory reduction in muscle tone is achieved. The daily dose should not exceed 36mg.

In case of spasticity due to neurological disorders, the dose should be adjusted to the needs of each patient. It is recommended 6mg / day divided into 3 doses, and gradually increase until an optimal therapeutic response is achieved (generally between 12 and 24mg / day).

Food increases the maximum plasma concentration and absorption of Tizanidine. Due to the short duration of the therapeutic effect, Pirdan treatment should be reserved for daily activities and times when relief from spasticity is most important.


Presentation

Pirdan 2 box containing 10 and 50 coated tablets.

Pirdan 4 box containing 10 and 50 coated tablets.


Storage

Store below 30 °C. Protected from humidity.