International Journal of Current Advanced Research
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International Journal of Current Advanced Research ISSN: O: 2319-6475, ISSN: P: 2319-6505, Impact Factor: SJIF: 5.995 Available Online at www.journalijcar.org Volume 6; Issue 8; August 2017; Page No. 5172-5175 DOI: http://dx.doi.org/10.24327/ijcar.2017.5175.0665 Review Article MUSCLE RELAXANTS IN DENTISTRY - A REVIEW Vaishnavi Sivakali Subramanian* and Dhanraj Department of Prosthodontics, Saveetha Dental college and Hospitals, Chennai ARTICLE INFO ABSTRACT Article History: A muscle relaxant is a drug that affects skeletal muscle function and decreases the muscle tone. It may be used to alleviate symptoms such as muscle spasms, pain, and hyperreflexia. Received 13th May, 2017 th Muscle relaxants in dentistry are often used in treating temporomandibuar joint disorders. Received in revised form 14 A temporomandibular disorder (TMD) is a very common problem affecting up to 33% of June, 2017 Accepted 6th July, 2017 th individuals within their lifetime. TMD is often viewed as similar to musculoskeletal Published online 28 August, 2017 disorders of other parts of the body, therefore the treatment often involves similar principles as other regions as well. This review article includes brief description of Key words: commonly used muscle relaxants in dentistry, that describes mechanism of action, Dentistry, Temporomandibular Disorders, metabolism, dosage and side effects of the drug. muscle relaxants, muscle spasm. Copyright©2017 Vaishnavi Sivakali Subramanian and Dhanraj. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. INTRODUCTION excursion, jaw locking, and noise at the joint with movement. In general TMD is divided into myofacial TMD or Many recent advances are approaching in medical technology, arthrogenic TMD. Myofacial TMD is associated with the pain and various muscle relaxant medicines are prepared and from hyperfunctioning muscles of mastication leading to applied which are safe, effective and non-depolarizing is chronic myositis. In contrast, arthrogenic TMD is associated always the key in clinical aesthetical practice. Muscle intracapsular pathology with pain at the level of the joint itself relaxants are commonly indicated for the treatment of two (4). different types of conditions: spasticity from upper motor neuron syndromes and muscular pain or spasms from The available comparative clinical studies are reviewed, and peripheral musculoskeletal diseases or injury such as low the pharmacology, metabolism and adverse effects of back pain. Muscle relaxants make up a heterogeneous group the oral SMRs are discussed briefly. The drugs covered are of drugs that mainly exert their pharmacologic effect centrally carisoprodol, chlorphenesin carbamate, chlorzoxazone, at the level of the spinal cord, the brainstem, or the cerebrum, cyclobenzaprine hydrochloride, diazepam, metaxalone, and that have an insignificant, if any effect, at the muscle fibre methocarbamol, and orphenadrine citrate, baclofen, level. Their centrally mediated mechanism of action can exert dantroleneand tizanidine. Some centrally acting muscle a clinically significant peripheral therapeutic effect (1). relaxants such as phenprobamate and mephenoxalone have antianxiety action that may be related in part to their action Temporomandibular disorders (TMD) result from (5), these muscle relaxants are useful in treating musculoskeletal dysfunction of the orofacial region affecting tempromandibulardisoders. masticatory muscles, temporomandibular joints (TMJ), and other associated structures. The main characteristics of these Cyclobenzaprine problems are facial and TMJ pain, headache, earache, Cyclobenzaprine is the most commonly used muscle relaxant. dizziness, masticatory muscle hypertrophy, limited mouth opening, locked jaw, abnormal teeth wear, joint sounds, and Structure: Cyclobexaprine where it structurally resembles others(2). Dentist must be aware on the proper diagnosis and tricyclic antidepressants and differs from amitriptyline by treatment of temporomandibular disorders, because they only one double bond. represent the second most frequent patients complaints (only Action: Its therapeutic effect is centrally mediated and carries less frequent than dental pain) (3). Symptoms are commonly no direct peripheral action on the affected muscles. Its main related to pain surrounding the joint and may include pharmacologic action occurs at the brainstem and spinal cord headache, periauricular pain, neck pain, decreased jaw levels and is partially explained by a depressant effect on the descending serotonergic neurons (6). *Corresponding author: Vaishnavi Sivakali Subramanian Metabolism: It is extensively metabolized in the liver and Department of Prosthodontics, Saveetha Dental College and excreted as a glucuronated metabolite through the kidneys. It Hospitals International Journal of Current Advanced Research Vol 6, Issue 08, pp 5172-5175, August 2017 possesses a fairly long half-life of approximately 18 hours and Metabolism: This drug is metabolized in the liver with can continue to accumulate for up to 4 days when meprobamate as its main metabolite. It is mainly excreted administered at a frequency of three times per day. Likewise, through the kidneys. Its metabolites are hydroxycarisoprodol, concomitant use with monoamine oxidase inhibitors is hydroxymeprobamate, and meprobamate, with meprobamate absolutely contraindicated because this combination can cause being the primary active metabolite. a hyperpyretic crisis or even death. Dosage: The usual adult dosage is 350 mg four times per day. Dosage: The initial starting dose should be 5 mg three times The most common side effect is drowsiness. per day on as needed basis and can be titrated up to 10 mg Sideffects: Other central nervous system adverse effects that three times per day per therapeutic effect or side effect. have been reported include ataxia, agitation, insomnia, and In patients with hepatic or renal insufficiency, it should others. Adverse effects such as tachycardia, postural initially be administered once per day given its relatively long hypotension, nausea, erythema multiforme, and eosinophilia half-life. Of note, one recent study showed equal efficacy of 5 have also been seen (10). and 10 mg doses, with the smaller dose showing a lower level of sedation (7). Diazepam Sideffects: The most common side effects are drowsiness, dry Diazepam has commonly been used in the treatment of mouth, fatigue, and headache, followed by less often muscle spasm, especially in the acute setting. It belongs to a occurring adverse effects of diarrhoea, dizziness, abdominal group of compounds called benzodiazepines, known for their pain, nausea, nervousness, blurred vision, and confusion (8). potent anxiolytic, sedative, as well as muscle relaxant effects. Metaxalone Mechanism: Their main mechanism of action is through central potentiation of the inhibitory g-aminobutyric acid Metaxalone occurs as a white crystalline powder with a bitter (GABA) effect through presynaptic facilitation of GABA taste that is insoluble in water and soluble in alcohol. release. Metaxalone is a centrally acting muscle relaxant with an unknown mechanism of action. Metabolism: Benzodiazepines are extensively metabolized in the liver into inactive and in some cases active metabolites. Metabolism: It is metabolized in the liver and excreted Compounds that lack active metabolites should be used as through the kidneys in the form of metabolites. first-line agents in the elderly and in patients with liver or Mechanism: Although metaxalone mechanism of action is kidney insufficiency. Such com- pounds are lorazepam, unknown, it is thought that metaxalone acts by depressing clonazepam, temazepam, and oxazepam. Excretion poly synaptic reflexes. Polysynaptics reflexes are pathways principally occurs through the kidneys. associated with muscle spasm. Whereas monosynaptic Sideffects: Some of the common side effects are drowsiness, pathway involves stretch reflexes, muscle tone and normal confusion, ataxia, cognitive impairment, memory loss, posture. agitation, and disinhibition. Of note, withdrawal symptoms Dosage: Typical adult dosing consists of 800 mg three to four may occur after only 4 to 6 weeks of use, and their potential times per day, mean peak plasma concentrations are attained for abuse should be taken into consideration(12). in 2 hours. The onset of action is usually within 1 hour and Botulinum Toxin the duration of action is about 4 to 6 hours. The drug has a plasma halflife of 2-3 hours. It is recommended to monitor The first indication that BoNT could be useful for treating liver function tests after initiation of this agent. pain was observed from anecdotal reports of patients treated for hyperfunctional facial lines who reported reduced Sideffects: Common side effects include drowsiness, frequency and severity of headache [13]. Soon thereafter, the dizziness, nervousness, nausea, and headache. The following pain-relieving effect of BoNT was reported during the rare but serious adverse reactions have been reported: treatment of oromandibular dystonia and cervical dystonia leukopenia, hemolyticanemia, jaundice, and hypersensitivity [14–18]. Today, BoNT is used for pain relief in numerous reactions (9) conditions including tension headaches, Carisprodol Mechanism of Action: BoNT is a 150-Kilodalton exotoxin Carisoprodol is still a commonly prescribed muscle relaxant produced