Pridinol: Anticholinergic Muscle Relaxant
Pridinol is a centrally acting anticholinergic and antihistaminic agent used as a skeletal muscle relaxant. It reduces painful muscle spasms by blocking muscarinic acetylcholine receptors and histamine H1 receptors in the central nervous system.
Available as oral tablets and injectable solution (often combined with diclofenac as Myotonolbee), pridinol is used for acute musculoskeletal pain syndromes, cervical spine disorders, and lumbar pain with muscle spasm.
Mechanism of Action
Pridinol acts as a competitive antagonist at muscarinic M1/M2 receptors and histamine H1 receptors in the CNS. This reduces spinal cord excitability and gamma-motor neuron activity, decreasing skeletal muscle tone without directly acting on the neuromuscular junction.
Indications & Use
Painful muscle spasms in cervical and lumbar spine syndromes, vertebrogenic pain, post-traumatic muscle tension. Often combined with NSAIDs (diclofenac) for combined analgesic and spasmolytic effect.
Dosage
Oral: typically 8 mg three times daily. Injectable: 4 mg i.m. or i.v. Pridinol/diclofenac combination (Myotonolbee): 1 vial i.m. once or twice daily. Duration usually limited to 1–2 weeks.
Side Effects
Anticholinergic effects: dry mouth, urinary retention, constipation, blurred vision, tachycardia. CNS: sedation, dizziness. Elevated intraocular pressure possible.
Drug Interactions
Additive anticholinergic effects with other anticholinergics, tricyclic antidepressants, antihistamines. CNS depressants potentiate sedation. Alcohol increases CNS depression.
Contraindications
Narrow-angle glaucoma, urinary obstruction (benign prostatic hyperplasia with residual urine), myasthenia gravis, severe cardiac arrhythmias, hypersensitivity. Caution in elderly and patients with cognitive impairment.
Frequently Asked Questions
Can I drive while taking pridinol?
Pridinol causes sedation and may impair reaction time. Driving or operating machinery is generally not recommended, especially during the first days of treatment.
How long does pridinol take to work?
The muscle relaxant effect begins within 30–60 minutes of oral administration and peaks at 1–2 hours. Injectable forms act more rapidly.
Is pridinol addictive?
Pridinol has no significant addiction potential. However, abrupt discontinuation after prolonged use should be avoided; gradual tapering is recommended.
References
- EMA assessment of pridinol-containing products
- AWMF Leitlinie Zervikalsyndrom
- German Drug Information Portal (DAZ)
Medical Disclaimer: This information is for educational purposes only and does not replace professional medical advice.