Antidepressants neuralgias

DPN, diabetic peripheral neuropathy PHN, post-herpetic neuralgia TCA, tricyclic antidepressant. 

Special situations of sudden-onset/sudden-resolution pain, especially along a nerve track, or neuralgias, may require an adjunct of an anticonvulsant and/or tricyclic antidepressant. 

Neuroanatomically both the locus coeruleus and the raphe nuclei project to the spinal cord where they gate sensory pathways from the skeletomuscular areas. As there is evidence that both noradrenaline and 5-HT are dysfunctional in depression, it is perhaps not surprising to find that the pain threshold is often reduced in patients with depression. Conversely, different types of antidepressants have been shown to have an antinociceptive effect in both rodent models of neuropathic pain, and clinically in fibromyalgia, chronic fatigue syndrome, postherpetic neuralgia and diabetic neuropathy. In general, it would appear that the dual action antidepressants (such as the TCAs and SNRIs) are more effective than the SSRIs. 

Phenytoin Adjunct in treatment of tricyclic antidepressant toxicity, muscle relaxant in treatment of muscle hyperirritability, treatment of digoxin-induced arrhythmias and trigeminal neuralgia... 

It is structurally and chemically related to tricyclic antidepressant drug imipramine and pharmacologically it is similar to diphenyl hydantoin sodium. It is effective in grandmal and psychomotor epilepsy and also in the treatment of trigeminal neuralgia (a condition characterized by paroxysms of intense pain of stabbing nature within the area of distribution of trigeminal nerve without sensory loss). 

Tricyclic antidepressants have efficacy in other disorders besides depression. They are useful in the management of chronic pain syndromes, neuralgias, migraine headaches and sleep disorders. 

Closely related to imipramine and other antidepressants, carbamazepine is a tricyclic compound effective in treatment of bipolar depression. It was initially marketed for the treatment of trigeminal neuralgia but has proved useful for epilepsy as well. 

Over the years, antidepressant drugs have become an important treatment option in chronic pain states, in their own right and as adjuncts to opiate treatment. In fact, tricyclic antidepressants are the mainstay of treatment of neuropathic pain conditions such as polyneuropathy, diabetic neuropathy, postherpetic neuralgia and peripheral nerve injury (Sindrup, 1997 Sindrup and Jensen, 1999). Other chronic pain states responsive to antidepressants include osteo- and rheumatoid arthritis, fibromyalgia, and chronic tension headache. 

A variety of drugs with antiepileptic, antispastic, or antidepressant activity are used to manage cranial neuralgias. These compounds are usually more useful than agents with general analgesic properties. 

The pain associated with diabetic peripheral neuropathy, trigeminal neuralgia, or cancer may predispose such patients to depression. Tricyclic antidepressants have been shown to be an effective adjunct in managing these and other similar conditions. 

Since the monoamine effects of tramadol resemble the effect of antidepressants, it has been compared with clomipramine + levomepromazine in patients with postherpetic neuralgia. The incidence of adverse effects was 77% with tramadol and 83% with clomipramine (SEDA-20, 81). 

Tricyclic antidepressants (TCAs) Imipramine, doxepin, nortriptyline, or desipramine (25-100 mg at bedtime) TCAs are generally reserved for patients with an additional indication (e.g., depression, neuralgia)... 

Carbamazepine is an anticonvulsant that is structurally related to tricyclic antidepressants such as amitriptyline and imipramine. Carbamazepine is effective in the treatment of psychomotor and grand mal seizures and pain from trigeminal neuralgia and, in combination with other drugs, for psychiatric disorders such as mania and extreme aggression. Carbamazepine is also occasionally used to control pain in persons with cancer. Carbamazepine was first mar-... 

They are particularly effective for neuropathic pain and their efficacy for post-herpetic neuralgia may be greater than that of the newer pregabalin [2]. Tricyclics are commonly used to treat headaches, fibromyalgia, neck and low back pain. The mechanism of the antinociceptive activity of the tricychc antidepressants is largely unknown, and appears to be distinct from then-antidepressant properties. It may be related to sodium chaimel blockade. Analgesic effects are achieved with lower doses and quicker onset than antidepressant effects. 

---