CDA Essentials 2017 • Volume 4 • Issue 6

27 Issue 8 | 2017 | S upporting Y our P ractice Muscle Relaxants Many consider cyclobenzaprine the drug of choice for generalized chronic muscle pain as it provides significant muscle pain relief and enhances quality and quantity of sleep. Efficacy and dosage Cyclobenzaprine has shown to be effective in in treating muscle spasms in the cervical and lumbar regions, suggesting it may be useful for patients with TMD. 20,35,36 Evidence suggests that a very low dose may also provide positive effects in terms of sleep physiology and pain alleviation. 39 To mitigate its sedating effect, cyclobenzaprine is commonly prescribed at a low dose (10 mg at bedtime) when treating TMD. The usual course of treatment encompasses a 30-day trial period followed by a 2-week washout period. If benefits are noted, a repeat of the prescription for 2–3 months may be necessary; however, long-term therapy should be comanaged with the patient’s physician. Several studies have demonstrated that carisoprodol is no more efficacious than placebo. 33,34 Adverse effects and drug interactions Muscle relaxants may cause significant sedation. Cyclobenzaprine’s chemical structure is similar to that of tricyclic antidepressants (TCAs), and it shares many of the properties of TCAs. It is therefore contraindicated for patients with hyperthyroidism and congestive heart failure, and it should be avoided during the acute phase of recovery from myocardial infarction and in patients with arrhythmias. Cyclobenzaprine may have life-threatening interactions with monoamine oxidase inhibitors (MAOIs), and it may enhance the risk of seizure in patients taking tramadol. Antidepressants Antidepressants are excellent medications for patients who are refractory to splint therapy. 41,42 Moreover, many patients who suffer from chronic pain have comorbid depression and disturbance in sleep patterns, 43,44 and pain may decrease with better sleep patterns. 37,44,45 Antidepressants should be used with caution. Patients should be comanaged with their physician to ensure they are medically stable enough to engage in long- term treatment, and the physician should manage all side effects. Efficacy and dosage TCAs (e.g., amitriptyline, nortriptyline, desipramine) exhibit clear analgesic efficacy in many chronic pain conditions. 41-44 Amitriptyline (25 mg/day) reduces pain and discomfort in patients with chronic TMJ pain. 37 Increasing the dose to 50–75 mg/day does not increase the analgesic effect. Some studies 44 proposed that the effects were no greater than those observed with a placebo, attributing reported differences to a psychogenic factor and to the difficulty of patients in measuring pain and discomfort. 44 Selective serotonin reuptake inhibitors (SSRIs) citalopram and paroxetine have been shown to relieve neuropathic pain symptoms. 51,52 Fluoxetine was also found to be effective in patients with idiopathic facial pain, 53 and escitalopram was found to reduce pain in patients with painful polyneuropathy. 54 Adverse effects and drug interactions TCAs are associated with sedation, dizziness, blurred vision, constipation and dry mouth. In dental patients taking TCAs, the amount of epinephrine should be limited to 0.04 mg as the administration of an exogenous catecholamine may cause adverse cardiovascular events. 4 Moreover, TCAs should be avoided in patients taking MAOIs, as this combination may lead to lethal serotonin syndrome. 20 TCAs should also be used with caution for patients with cardiac disease and among the elderly. SSRIs have been associated with fewer anticholinergic, antihistaminergic and antiadrenergic effects, although paroxetine has a relatively high anticholinergic potency. 50 SSRIs cause GI disturbances, headache, sexual dysfunction, dry mouth and sweating. 50 Anticonvulsants Anticonvulsants are widely used to treat neuropathic pain. It has been proposed that they be used as adjuvant analgesics in TMD, particularly for patients with a history of failed TMJ surgery or those with long- standing unremitting pain. 20 Gabapentin significantly reduces TMD pain and decreases tenderness in the masticatory muscles. 61 While pregabalin has been shown to be effective for a wide array of painful neuropathic conditions, 62-65 no studies have demonstrated its effect on TMD pain. Adverse effects Adverse effects are mild to moderate and dose-dependent. 20 Dizziness and somnolence are most frequently reported. Less common adverse effects include dry mouth,