Tizanidine

1 medicine

Tizanidine is a muscle relaxant that must never be combined with fluvoxamine or ciprofloxacin, medicines that can raise its blood levels and cause dangerously low blood pressure.

Zanaflex

Tizanidine

2/4mg

Zanaflex is a painkillers medication containing Tizanidine, available as 2/4mg tablets.

from $0.79 / tablet View

Key facts

  • Tizanidine is a short-acting alpha-2 adrenergic agonist that relaxes tight or spastic muscles by calming overactive nerve signals in the spinal cord.
  • It is taken as tablets or capsules, usually several times a day, and its effects wear off within a few hours, so doses are often timed around when muscle tightness is worst.
  • Never combine tizanidine with fluvoxamine or ciprofloxacin. Both block the enzyme that clears tizanidine from the body, which can send blood levels very high and cause a severe, dangerous drop in blood pressure.
  • Seek urgent care for fainting, a very slow or fast heartbeat, or extreme drowsiness that will not lift.

What tizanidine treats

Tizanidine treats spasticity and muscle spasm, the painful tightening of muscles seen in multiple sclerosis, spinal cord injury, and some back and neck conditions. It is used short-term for acute muscle spasm and longer-term for ongoing spasticity. It does not treat the underlying nerve or spinal condition, only the muscle tightness it causes.

How tizanidine works

Tizanidine acts on alpha-2 receptors in the spinal cord, where it dampens the nerve signals that keep muscles contracted. This reduces spasm and muscle tone without directly weakening the muscle itself.

Before you take it

  • Do not take tizanidine with fluvoxamine or ciprofloxacin. These drugs block the CYP1A2 enzyme that breaks tizanidine down, and the resulting high levels can cause severe hypotension, extreme sedation, and a slowed heart rate.
  • Tell your prescriber about liver disease, low blood pressure, or any other blood-pressure-lowering medicine, including other muscle relaxants.
  • Avoid alcohol and other sedating medicines. They add to tizanidine's drowsiness and can deepen the drop in blood pressure.
  • Stopping tizanidine suddenly after prolonged use can cause a rebound rise in blood pressure and heart rate; ask your prescriber whether you need to taper off.

Side effects

Common effects include drowsiness, dry mouth, weakness, and a light-headed feeling, especially on standing.

Stop and seek urgent medical care for any of these:

  • Fainting or a severe drop in blood pressure.
  • A very slow, fast, or irregular heartbeat.
  • Yellowing of the skin or eyes, dark urine, or persistent nausea, which can signal liver injury.
  • Extreme drowsiness or confusion that does not improve.

Safety essentials

  • The fluvoxamine and ciprofloxacin interaction is absolute: combining either with tizanidine can raise blood levels several-fold and cause life-threatening low blood pressure. Tell every prescriber and pharmacist that you take tizanidine before starting any new medicine.
  • Rise slowly from sitting or lying down, since tizanidine can make you light-headed.
  • Your prescriber may check liver function periodically, since tizanidine can affect the liver at higher doses.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.