Insomnia from TCAs

Medications that enhance norepinephrine activity are used to treat depression and ADHD. Boosting norepinephrine can also produce numerous side effects including nervousness and anxiety, insomnia, and loss of appetite. With mirtazapine and the TCAs, these side effects are usually not a problem because these antidepressants also block histamine receptors. Their antihistamine effects promote increased appetite and drowsiness that tend to offset the side effects that might be experienced from increased norepinephrine activity. 

Excessive central stimulation, usually exhibited as tremors, insomnia and hyperhidrosis, can occur following therapeutic doses of the MAOIs, as can agitation and hypomanic episodes. Peripheral neuropathy, which is largely restricted to the hydrazine type of MAOI, is rare and has been attributed to a drug-induced p)n idoxine deficiency. Such side effects as dizziness and vertigo (presumably associated with hypotension), headache, inhibition of ejaculation (which is often also a problem with the TCAs), fatigue, dry mouth and constipation have also been reported. These side effects appear to be more frequently associated with phenelzine use. They are not associated with any antimuscarinic properties of the drug but presumably arise from the enhanced peripheral sympathetic activity which the MAOIs... 

There have been three randomized clinical trials and multiple case reports and open-label trials with the tricyclic antidepressants (TCAs) in PTSD, although only one study of childhood PTSD (Southwick et al., 1994) has been reported. Robert et al. (1999) reported the use of low-dose imipramine (1 mg/kg) to treat symptoms of ASD in children with burn injuries. In this study, 25 children ages 2 to 19 years were randomized to receive either chloral hydrate or imipramine for 7 days. Ten of 12 subjects receiving imipramine experienced from half to full remission of ASD symptoms, whereas 5 of 13 subjects responded to chloral hydrate. Sleep-related flashbacks and insomnia appeared to be particularly responsive to treatment. 

As with most data for reboxetine, this information primarily comes from summary papers rather than primary sources (473, 474). With this caveat, the adverse-effect profile of reboxetine is consistent with its pharmacology as an NSRI. Thus, it is similar to that of desipramine and maprotiline but without the risk of serious CNS (i.e., seizures, delirium) or cardiac (i.e., conduction disturbances) toxicity. The most common adverse effects of reboxetine are dry mouth, constipation, urinary hesitancy, increased sweating, insomnia, tachycardia, and vertigo. Whereas the first three adverse effects are commonly called anticholinergic, they are well known to occur with sympathomimetic drugs as well. In other words, these effects can be either the result of decreased cholinergic tone or increased sympathetic tone, although they tend to be more severe with the former than the latter. In contrast to TCAs, reboxetine does not directly interfere with intracardiac conduction. The tachycardia produced by reboxetine, however, can be associated with occasional atrial or ventricular ectopic beats in elderly patients. 

At the present time, the TCAs are used primarily in depression that is unresponsive to more commonly used antidepressants such as the SSRIs or SNRIs. Their loss of popularity stems in large part from relatively poorer tolerability compared with newer agents, to difficulty of use, and to lethality in overdose. Other uses for TCAs include the treatment of pain conditions, enuresis, and insomnia. 

The monoamine oxidase inhibitors are associated with a number of undesirable side effects including weight gain, postural hypotension, sexual dysfunction, and insomnia. The most serious side effect is the risk of tyramine-re-lated hypertensive crisis, often referred to as the "cheese effect," which can be fatal. To avoid this situation patients taking MAOIs must limit their tyramine intake, and the restrictive diet required to accomplish this leads to low patient compliance. A similar interaction occurs when switching patients from MAOI to SSRI therapy, and a minimum 2-week washout period before commencement of SSRI therapy is essential to allow MAO levels to return to normal. The therapeutic effects of the TCAs derive from their inhibition of serotonin and norepinephrine uptake, al-... 

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