Microsoft word - wspa-wa rx cns muscle relaxants pearls.doc

CNS Muscle Relaxants
Clinical Pearls for the Washington Rx Therapeutic Interchange Program (TIP)
Steve Riddle, BS Pharm, BCPS

Background
In 2003, the Washington State Pharmacy and Therapeutics Committee (P&T), the agency directors of the Department of
Social and Health Services-Medical Assistance Administration (DSHS-MAA), Labor and Industries (L&I), and the Health
Care Authority-Uniform Medical Plan (UMP) declared baclofen, chlorzoxaxone, cyclobenzaprine and methocarbamol to be
the “preferred” CNS muscle relaxants for patients covered by their prescription insurance. Patients currently using “non-
preferred” agents” must be evaluated for conversion to a preferred agent. Furthermore, patients presenting
with prescriptions for non-preferred agents from “endorsing practitioners” (i.e., providers that have signed the TIP
agreement) may be automatically converted to preferred agents by pharmacists once this program is operational.
Purpose
The purpose of this document is to inform pharmacists of the clinical, safety and cost rationale for these policy changes and
to optimize their ability to assure safe and effective conversion of patients to the appropriate agents.
Washington State Evidence Based Preferred Drug List Preferred CNS Muscle Relaxants are:
Baclofen (generic)
Chlorzoxazone (generic)
Cyclobenzaprine (generic)
Methocarbamol (generic)

Overview
Skeletal muscle relaxants are a mixed group of medications that are used to treat two different types of conditions:
1) Musculo-skeletal conditions causing tenderness and muscle spasms include fibromyalgia, tension headaches, neck 2) Spasticity, a clinical condition characterized by increased muscle tone from such neurological conditions as
Currently Available Agents and Muscle Relaxant Applications
For Muscle Spasm:
For Spasticity
*Washington State Evidence Based Preferred Drug List Agents
Clinical Efficacy Summary
ƒ All muscle relaxants are effective for muscle spasm except for metaxalone, which was not more effective than
ƒ Baclofen, dantrolene, and tizanidine were as effective as diazepam for spasticity.
Diazepam was not studied in this group as it is used primarily for symptoms of anxiety. ƒ Cyclobenzaprine has the largest body of evidence supporting its effectiveness.
Safety Comparisons
ƒ Carisoprodol is a controlled substance in Oregon because of its potential for addiction.
ƒ Dantrolene is associated with rare but fatal liver toxicity.
ƒ Because of the potential for adverse effects, use of tizanidine requires that the patient’s liver function be

Evidence-Based Drug Reviews are available at http://www.oregonrx.org

Source: http://aeholland.com/cnsmusclerelax404.pdf