Amitriptyline Opioids

Antidepressants are used in the treatment of neuropathic pain and headache. They include the classic tricyclic compounds and are divided into nonselective nor-adrenaline/5-HT reuptake inhibitors (e.g., amitriptyline, imipramine, clomipramine, venlafaxine), preferential noradrenaline reuptake inhibitors (e.g., desipramine, nortriptyline) and selective 5-HT reuptake inhibitors (e.g., citalopram, paroxetine, fluoxetine). The reuptake block leads to a stimulation of endogenous monoaminer-gic pain inhibition in the spinal cord and brain. In addition, tricyclics have NMDA receptor antagonist, endogenous opioid enhancing, Na+ channel blocking, and K+ channel opening effects which can suppress peripheral and central sensitization. Block of cardiac ion channels by tricyclics can lead to life-threatening arrhythmias. The selective 5-HT transporter inhibitors have a different side effect profile and are safer in cases of overdose [3]. 

Agents Acetaminophen or NSAID combinations with opioids Adjuncts Tricyclic antidepressants Anticonvulsants Radiopharmaceuticals (Bone pain) Acetamnophen (See above) Opioids Titrate Amitriptyline 10-50 mg Imipramine 10-50 mg NSAIDs (See above) Gabapentin (Neurontin) 3.6 g... 

One of the main side-effects of opioid analgesics, such as codeine and tramadol, is constipation. Amitriptyline (tricyclic antidepressant) and orphenadrine tend to have antimuscarinic properties, resulting in side-effects such as constipation. Senna is a stimulant laxative indicated in constipation. 

In general, the concurrent use of most opioids and tricyclics is uneventful, although lethargy, sedation, and respiratory depression have been reported. Tramadol should be used with caution with tricyclic antidepressants because of the possible risk of seizures and the serotonin syndrome. Dextroproposyphene may cause moderate rises in the serum levels of amitriptyline and nortriptyUne, and methadone may moderately raise desipramine levels. The bioavailability and the degree of analgesia of oral morphine is increased by clomipramine, desipramine and possibly amitriptyline. 

A small study in healthy subjects found no problems when moclobemide was given 24 hours after clomipramine. However, the serotonin syndrome occurred in 3 patients when clomipramine was replaced by mo-clobemide without a washout period or with only a 24-hour washout period, " and in another patient when moclobemide was replaced by clomipramine after only 12 hours. A fatal case of the serotonin syndrome occurred in a patient taking clomipramine and amitriptyline, with symptoms manifesting within 30 minutes of a 300-mg dose of moclobemide. Two other patients developed fatal serotonin syndrome after taking moderate overdoses of moclobemide and clomipramine. The serotonin syndrome has been reported in at least 8 other cases of moclobemide and clomipramine overdose, one of which also involved tramadol (see also MAOIs + Opioids Tramadol, p.ll41), another fluoxetine (see also MAOIs or RIMAs + SSRIs, p.l 142), and yet another buspirone (see also MAOIs or RIMAs + Buspirone, p.l 133). Conversely, a case of an overdose of moclobemide and clomipramine resulted in no adverse effects except sinus tachycardia. ... 

Cancer pain tricyclic antidepressants may be a helpful adjuvant in treating visceral and neuropathic pain of malignancy. Consider using them alone or as adjuncts to opioid analgesics for neuropathic symptoms in cancer pain such as burning, tingling, electric shock and sharp sensations. If minimal medical comorbidities are present, consider a rapid titration to maximum effective dose with tolerable side effects (150 mg/day for amitriptyline or nortriptyline). 

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