Open Experience with a New Myorelaxant Agent for Low Back Pain
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Open Experience with a New Myorelaxant Agent for Low Back Pain S. Sartini, A. Ferrini* L. Guerra** Service of Rehabilitation and Functional Reeducation, S. Orsola-Malpighi Hospital, Bologna (Italy) *Division of Orthopaedics and Traumatology, Hospital of Vignola (Modena, Italy); **Medical Service Alfa Wassermann, Bologna (Italy). 1 KEY WORDS: Myyrelasant, Eperisone were reported, such as lightheadness, hydrochloride, and Chronic low back occasional vertigo and/or loss of equilib- 3 2 pain rium, mild somnolence, and epigastric pain.1 In almost all cases, there was no need to interrupt the treatment, and the ABSTRACT reactions spontaneously recovered. Eperisone hydrochloride has been It is noteworthy to mention that both recently proposed as a muscle relaxant the activities with eperisone, ie, analge- for treatment of muscle contracture and sia and muscle relaxation, were achieved chronic low back pain (LBP), being with 1 drug only, while it is common devoid of clinically relevant sedative practice in rheumatology to combine a effects on central nervous system (CNS). painkiller with a muscle relaxant in This view has been confirmed by our order to achieve a satisfactory result experience in a series of 100 patients with both symptoms. Moreover, because with LBP and spinal muscle contracture, of the lack of significant effects on the treated with a full eperisone dose (300 CNS such as drowsiness, eperisone rep- mg/day) for ten consecutive days. resents a valuable alternative to the tra- The treatment achieved a consistent ditional centrally acting muscle analgesic and muscle relaxant activity relaxants, whose use has been signifi- across all of the patients. Both “sponta- cantly limited in recent years by their neous pain” and “pain on movement” CNS adverse effects in spite of a well- were significantly decreased, as did the documented therapeutic efficacy. resistance encountered by the investiga- tor to passive movements, the antalgic INTRODUCTION rigidity and the muscle contracture. As a Chronic low back pain (LBP) is one of consequence, the treatment with the most common debilitating condi- eperisone resulted in a lower rigidity of tions reported by patients, and repre- low back and an improved motility for sents a substantial burden on the patients. healthcare system,1 with approximately Only 7 cases of adverse reactions 45% of the adult population experienc- 226 Vol. 8, No. 2, 2008 • The Journal of Applied Research ing LBP annually. Direct cost for diag- market for the management of painful nosis and treatment is reported to be conditions sustained by a muscle con- higher than 23 billion dollars in the tracture.14,15,16 U.S.A. in 1990.2 Together with knee and According to results achieved with hip osteoarthritis, LBP is one of the other compounds belonging to the same leading causes of disability in European pharmacological class, the mechanism of countries3 as well, and it is the 10th most action of eperisone is believed to be a common complaint in outpatient office blockade of sodium channels; in addi- visits.4 tion, these compounds, including Analgesics such as non-steroidal eperisone, are reported to have a anti-inflammatory drugs (NSAIDs), marked effect on voltage-gated calcium paracetamol, and opioids are the most channels.17 These data suggest that largely used medications for sympto- eperisone and its analogues may exert matic treatment of LBP. However, tradi- their spinal reflex inhibitory action pre- tional NSAIDs are associated with an dominantly via a presynaptic inhibition increased risk for serious upper gas- of the transmitter release from the pri- trointestinal (GI) complications, includ- mary afferent endings via a combined ing bleeding and perforation; action on voltage-gated sodium and cal- nephrotoxicity, including oedema, hyper- cium channels.18 tension, and acute renal failure; conges- More importantly, eperisone appears tive heart failure; and adverse to be devoid of clinically relevant seda- reproductive outcomes5,6,7. Paracetamol tive effects on CNS, as it has been is generally considered to be safer and reported in trials involving patients with better tolerated than NSAIDs when myelopathy or tropical spastic parapare- used at therapeutic doses, but the results sis;19 patients with neurogenic bladder;xx of a recent epidemiological study seem and patients with muscle cramps second- to indicate that high doses of paraceta- ary to liver diseases.20 The lack of seda- mol may involve the same risk for upper tive effects, together with the lack of GI complications as traditional those GI adverse effects that are typical NSAIDs.8 Opioids such as oxymor- of traditional NSAIDs, represent the phone,9 oxycodone,10,11 tramadol,12 or most important advantage of eperisone, tramadol, in combination with paraceta- keeping in mind that patients with LBP mol,13 are effective analgesics. However, are not usually young and, therefore, at somnolence or other detrimental effects high risk for NSAID-induced GI toxicity. on CNS, and constipation, are observed in a percentage of patients ranging PATIENTS AND METHODS between 3% and 20%. We have screened 100 consecutive Central muscle relaxants (CMRs) patients of both sexes, among those are most often used for treating muscle seeking our centres for medical advise spasticities of neurological origin, while and healthy assistance because of LBP. their use for minor complaints, such as Forty patients were enrolled at the acute LBP, has been limited by their Service of Rehabilitation and Functional adverse CNS effects. Among these com- Reeducation, S. Orsola-Malpighi pounds, eperisone hydrochloride has Hospital, Bologna (Italy), and 60 recently emerged as antispastic agent patients at the Division of Orthopaedics with an improved profile of safety com- and Traumatology, Hospital of Vignola pared to other drugs of the same phar- (Modena, Italy). macological class; in particular, Main criteria for inclusion were eperisone has been introduced on the acute or relapsing LBP, moderate to The Journal of Applied Research • Vol. 8, No. 3, 2008 227 Table 1. Effects of a 10-day treatment with eperisone in 100 patients with low back pain of sci- atic origin. Results are reported as means ± standard deviation either of a 10-cm VAS (sponta- neous pain and pain on movement); a 5-point scale (resistance to passive movements; antalgic rigidity, muscular contracture, joint functional impairment); or centimetres (“hand-to- floor” distance). Statistically significant differences: * p<005 and ** p<0.01 vs. baseline; °° p<0.01 vs. day 3. BASELINE DAY 3 DAY 10 Spontaneous pain (VAS) 6.49 ± 0.12 5.40 ± 0.15** 3.54 ± 0.18°° Pain on movement (VAS) 7.28 ± 0.12 6.08 ± 0.17** 4.06 ± 0.20°° Resistance to passive movements 2.98 ± 0.07 2.45 ± 0.08** 1.63 ± 0.08°° Antalgic rigidity 3.18 ± 0.07 2.56 ± 0.07** 1.66 ± 0.09°° Muscle contracture 3.17 ± 0.07 2.56 ± 0.08** 1.62 ± 0.09°° Spine functional impairment 2.74 ± 0.10 2.24 ± 0.09** 1.54 ± 0.09°° “Hand-to-floor” distance (cm) 58.03 ± 3.21 48.71 ± 2.58* 36.55 ± 2.44°° severe, with no finding of severe spinal movement induced by the investigator) diseases at a Rx examination of lumbar were assessed by means of a 10-cm visu- spinal tract, such as spondilitis, fractures, al analogue scale (VAS); the patient was cancers, severe arthrosis and osteoporo- asked to score the pain by ticking off the sis. Muscular diseases, such as myositis, scale between 0 (no pain) and 10 polimyositis, muscular dystrophia and (unbearable pain). myotonia, were criteria for exclusion, as In addition, the resistance to passive well as any other severe disease affect- movement, the antalgic rigidity, and the ing neurological or cardiovascular sys- muscle contracture, were evaluated by tems, liver and kidney. Other criteria for the investigator by means of a 5-digit exclusion were history of hypersensitivi- scale (0 = absent; 1 = minimum; 2 = ty to the test compound; any anti-inflam- mild; 3 = moderate; 4 = severe); the matory and/or analgesic drug given in functional impairment was also scored the last 24 hours; pregnant or nursing by means of semiquantitative scale (0 = mothers; disturbances of nociception none; 1 = ≤ 25%; 2 = between 25 and and/or proprioception that could nega- 50%; 3 = between 50% and 75%; 4 = > tively affect neuronal reflexes and motil- 75%). Finally, the patients were asked to ity; any condition that could affect bend forward and try to touch the floor drugs’ absorption and disposition; and with fingers. The remaining distance ongoing infective diseases. between fingers and ground (“hand-to- The patients gave their informed floor” distance) was measured (cm). consent to taking part into the trial, and All these assessments were repeated then they were treated with eperisone after 3 and 10 days of treatment. At hydrochloride 100 mg 3 times daily (tid.) these times, the patients were asked a for 10 consecutive days. The medication non-leading question such as “Have you was given at 6:00 AM., 2:00 PM. and felt different in any way since starting 10:00 PM. Other non-analgesic medica- treatment or since the last visit?” in tions were allowed during the study for order to identify any adverse event specific diseases, but their dosage occurring during treatment. At the end remained unchanged for all the trial. of the study, a full lab examination At baseline (day 0), the “sponta- (hematology, blood chemistry, and uri- neous pain” and the “pain on move- nalysis) was performed, and the physi- ment” (pain provoked by a passive cians were asked to give their judgment 228 Vol. 8, No. 3, 2008 • The Journal of Applied Research about the efficacy of the treatment by line, to 48.71 cm at day 3 (-16%) and to means of a 5-digit scale (nil; light; mod- 36.55 cm at day 10 (-47%) (p < 0.01) erate; good; excellent efficacy).