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Anticholinergic muscle relaxant Pregnancy: This medicinal product is contraindicated in the first trimester of pregnancy. During the further course of pregnancy, the medicinal product may only be used after a careful medical consideration, under medical supervision and only if absolutely necessary. Breast-feeding: there are no data on the passage of pridinol into human milk; use during breastfeeding should be avoided.

Pridinol

Pridinol is a centrally and peripherally acting muscle relaxant with anticholinergic properties, used for painful skeletal muscle spasm.

Adult dose

Dose: 1.5-3 mg pridinol three times daily, for central and peripheral muscle spasms (lumbar pain, torticollis, general muscle pain) in adults
Route: Oral
Frequency: 3 times daily
VERBATIM UK SPC §4.2 (Myopridin 3 mg tablets): 'The recommended dose is 1.5 – 3 mg pridinol 3 times daily The duration of administration is decided by the treating doctor. Administration is independent of meals, with the onset of the effect being faster when the medicinal product is taken before meals. Patients who suffer from hypotension should take the tablets after meals to reduce the risk of fainting. Children and adolescents No data are available Method of administration For oral use. The tablets should be taken with sufficient fluid (e.g. 1 glass of water) and not chewed.' STRENGTH, §2: 'One tablet contains 3.02 mg pridinol (as 4 mg pridinol mesilate).' The SPC dose is expressed in mg of PRIDINOL (base), not mg of the mesilate salt, and the SPC does not state the dose in tablets. §4.1: 'Central and peripheral muscle spasms: lumbar pain, torticollis, general muscle pain, in adults.' The SPC prints no maximum daily dose, so none is given. Children and adolescents: no data are available, so there is no paediatric block.

Dose adjustments

Renal

UK SPC §4.4: use with caution in patients with severe renal insufficiency because higher and/or longer-lasting blood levels must be expected. No dose figure is given.

Hepatic

UK SPC §4.4: use with caution in patients with severe hepatic insufficiency because higher and/or longer-lasting blood levels must be expected. No dose figure is given.

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via MHRA Products — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients
  • Glaucoma
  • Prostate hypertrophy
  • Syndrome with urinary retention
  • Gastrointestinal obstructions
  • Arrhythmia
  • First trimester of pregnancy

Side effects

  • Anticholinergic effects, particularly with other anticholinergics: dry mouth, thirst, transient visual disorder (mydriasis, difficulties with accommodation, photosensitivity, slight increase in intraocular pressure), redness and dryness of the skin, bradycardia followed by tachycardia, micturition disorders, constipation and, very rarely, vomiting, dizziness and unsteady gait
  • Hypersensitivity (pruritus, erythema, mucosal oedema, dyspnoea)
  • Restlessness, anxiety, depression, hallucinations
  • Dizziness, headache, speech disorder, disturbance in attention, abnormal coordination, taste disorder, tremor, paraesthesia
  • Glaucomatocyclitic crises in angle closure glaucoma; acute urinary retention in benign prostate hyperplasia
  • Circulatory collapse, hypotension, tachycardia, arrhythmia, bradycardia
  • Muscular weakness, fatigue, asthenia

Interactions

  • Myopridin potentiates the effect of anticholinergics such as atropine

Monitoring

  • Use with caution in the elderly, who may have higher and/or longer-lasting blood levels
  • In patients who suffer from hypotension the risk of circulatory problems (fainting) may be increased - take the tablets after meals
  • Contains lactose (143.5 mg per tablet): not for patients with galactose intolerance, total lactase deficiency or glucose-galactose malabsorption

Clinical monograph

How it works

It relieves muscle spasm through antimuscarinic activity and central effects that reduce excessive muscle tone, rather than acting on a specific neuromuscular target.

Prescribing in practice

  • Its anticholinergic action makes it unsuitable in conditions such as narrow-angle glaucoma, significant urinary retention, and certain gastrointestinal obstructive disorders, where it is contraindicated.
  • It can cause drowsiness and impair driving and skilled-task performance, with additive sedation alongside alcohol and other CNS depressants.
  • Caution is needed in older patients and those sensitive to anticholinergic effects such as dry mouth, blurred vision, and constipation.

Monitoring

Monitor for anticholinergic adverse effects and excessive sedation, particularly in older or susceptible patients.

Counselling the patient

  • This medicine may make you drowsy; do not drive or operate machinery until you know how it affects you.
  • Avoid alcohol, which can increase drowsiness.
  • Tell your clinician about dry mouth, difficulty passing urine, or eye problems.

Evidence & guidelines

Pridinol is used as a skeletal muscle relaxant for painful muscle spasm based on established clinical use; consult current prescribing references for indication-specific guidance.

Reference: Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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