Stimulants with SSRIs

Although all patients with depression should undergo a thorough medical evaluation, no specific tests are required before SSRI therapy is initiated. The usual starting doses of SSRIs are summarized in Table 2-1. These standard doses should be decreased by 50% in patients with hepatic disease and in elderly persons. In addition, patients with panic disorder or significant anxiety symptoms are often intolerant of the initial stimulating side effects that commonly occur with SSRI use. In these cases, the initial dose should be decreased... 

Some patients may experience jitteriness, restlessness, muscle tension, and disturbed sleep. These side effects typically occur early in treatment, before the antidepressant effect. All patients should be informed of the possibility of these side effects and be reassured that if they develop, they tend to be transient. In patients with preexisting anxiety, therapy should be started at low doses, with subsequent titration as tolerated. If overstimulation occurs with this approach, it will be less likely to be severe enough to result in nonadherence with therapy. The short-term use of a benzodiazepine also may help the patient cope with overstimulation in the early stages of treatment until tolerance to this side effect occurs. Despite these common transient stimulating effects, SSRIs are clearly effective in patients with anxiety or agitated depression. Similarly, insomnia that commonly occurs early in treatment may be tolerable if the patient is reassured that the side effect will be transient. Symptomatic, short-term treatment with a hypnotic at bedtime is reasonable. 

Drug interactions for the RIMAs include interaction with SSRI antidepressants, which can cause the 5-HT syndrome (see the discussion of SSRIs). The effect of stimulant drugs, such as methylphenidate and dextroamphetamine (used to treat ADHD), may be increased. Some over-the-counter cold and hay fever decongestants (i.e., sympathomimetic amines) can have increased stimulant effects. Selegiline, a selective MAO-B used for Parkinson s disease, should not be used concurrently with the RIMAs. Unlike the irreversible MAOIs, no significant interactions with foods occur, because the selective inhibition of MAO-Adoes not stop the metabolism of tyramine. The RIMAs must not be taken concurrently with a nonreversible MAOI. 

Treatment with imipramine, the most studied TCA, leaves 45% to 70% of patients panic free. Both desipramine and clomipramine have demonstrated effectiveness in PD as well. Despite their efficacy, TCAs are considered second- or third-line pharmacotherapy due to poorer tolerability and toxicity on overdose.48,49 TCAs are associated with a greater rate of discontinuation from treatment than SSRIs.53 PD patients taking TCAs may experience anticholinergic effects, orthostatic hypotension, sweating, sleep disturbances, dizziness, fatigue, sexual dysfunction, and weight gain. Stimulant-like side effects occur in up to 40% of patients.49... 

In addition to this serious diet-drug interaction, irreversible MAOIs also potentiate the effects of sympathomimetic drugs like ephedrine found in over-the-counter cold remedies and recreational stimulants like amphetamine. The MAOIs also interact with drugs that increase synaptic concentrations of 5-HT, such as the tricyclic antidepressant clomipramine and the herbal SSRI antidepressant St John s wort (Hypericum spp.). The resulting serotonin syndrome is characterised by hyperthermia and muscle rigidity. While devoid of these side effects the reversible MAO-A inhibitor moclobemide has yet to establish itself as a first-line alternative to the SSRIs. 

The most commonly used therapies for anxiety and depression are selective serotonin reuptake inhibitors (SSRIs) and the more recently developed serotonin noradrenaline reuptake inhibitors (SNRIs). SSRIs, which constitute 60% of the worldwide antidepressant and antianxiety market, are frequently associated with sexual dysfunction, appetite disturbances and sleep disorders. Because SSRIs and SNRIs increase 5-HT levels in the brain, they can indirectly stimulate all 14 serotonergic receptor subtypes [2,3], some of which are believed to lead to adverse side effects associated with these drugs. Common drugs for short-term relief of GAD are benzodiazepines. These sedating agents are controlled substances with addictive properties and can be lethal when used in combination with alcohol. The use of benzodiazepines is associated with addiction, dependency and cognitive impairment. 

Serotonin-Boosting Antidepressants. Antidepressants that enhance serotonin activity in the brain have also been studied in ADHD. In particular, fluoxetine (Prozac) and the serotonin-selective TCA clomipramine (Anafranil) have been the most extensively evaluated, with mixed success. They provide some benefit for aggression and impulsivity but don t significantly improve the poor attention of ADHD. As a result, the SSRls and other serotonin-boosting antidepressants do not appear to be effective first-line treatments for ADHD. Conversely, depressed patients without ADHD often show improvements in symptoms of concentration and attention when treated with a SSRI. Although SSRls are not widely used in the treatment of ADHD, they may be worthy of consideration in ADHD patients whose impulsivity is not controlled by stimulants alone. Those with comorbid conduct disorder or ODD who are prone to agitation and at times violent outbursts may be helped by the addition of a SSRI. 

With regard to generalized anxiety disorder, it has been postulated that an overactivity of the stimulatory 5-HT pathways occurs. Drugs such as buspirone and ipsapirone are effective in such conditions because they stimulate the inhibitory S-HT a autoreceptors on the raphe nuclei and thereby reduce serotonergic function. It is noteworthy that the SSRIs often worsen anxiety initially because they temporarily enhance serotonergic function. Adaptive changes in the pre- and postsynaptic 5-HT receptors then occur leading to a reduction in the anxiety state. 

The safety and efficacy of combined SSRI and stimulant pharmacotherapy have been addressed in two open studies. Gammon and Brown (1993) reported on the successful addition of fluoxetine to stimulants in the treatment of 32 patients with ADHD with comorbid depressive and anxiety disorders (Gammon and Brown 1993). These children with comorbid conditions had failed to respond to methylphenidate alone. Another report detailed the addition of methylphenidate to SSRI treatment (Findling, 1996). Depressed children and adults with comorbid ADHD were treated with either fluoxetine or sertraline. While depressive symptoms remitted, ADHD symptoms persisted. Methylphenidate was added and successfully treated the ADHD symptoms. In both investigations, the combined treatment was well tolerated. 

Case reports have suggested that adding stimulant medications or combining a SSRI and a TCA or bupropion may also be effective (APA, 2000), but these combinations need to be done with caution, given the possibility of drug interactions (e.g., SSRIs cytochrome inhibition leading to toxic TCA levels). Additionally, in adults, the combination of antidepressants and psychotherapy (CBT, IPT) for patients with severe or treatment-resistant depression has been found useful (APA, 2000 Keller et al., 2000). 

Nausea is a common early side effect of all SSRIs. Early nausea is probably attributable to the stimulation of serotonin type 3 (5-HT3) receptors in the gastrointestinal tract, which downregulate after several weeks of treatment. Hence this side effect is both dose dependent and transient. Some patients report less nausea if they take the medication with food. Although rarely needed, medication that blocks the 5-HT3 receptor (e.g., ondansetron) can be used to reduce SSRI-induced nausea. 

MAOIs fall between TCAs and SSRIs in terms of lethality in overdose. Most complications related to MAOI overdose arise from the drugs stimulation of the sympathetic nervous system. MAOIs are most dangerous when patients experience hypertensive crises as the result of ingesting foods with high tyramine content. 

Stimulants such as amphetamine and methylphenidate have been used to treat depression for many years. Stimulants should not be used alone, except perhaps in geriatric patients with prominent apathy, medically ill patients with depression, or patients with poststroke depression (Lingam et al. 1988). However, psychostimulants are useful for augmentation of antidepressant therapy in refractory depression, and they are generally safe, even for most patients with cardiac disorders. The nonamphetamine stimulant modafmil was found to be helpful in a recent placebo-controlled study involving 311 patients with partial response to SSRIs (Fava et al. 2005). 

Because long-term exposure to high-dose benzodiazepines may place some patients at risk for physical and psychological dependence, we recommend the use of antidepressants for the treatment of panic disorder. For most patients, SSRIs should be considered first-line agents. The choice should be based on the factors discussed in Chapter 2. MAOls are usually reserved for patients whose symptoms have not responded to SSRIs and TCAs. A major caveat is that patients with panic disorder initially may be highly sensitive to the stimulant effect of small doses of antidepressants. For highly anxious patients with panic disorder, treatment may be... 

Although more stimulating antidepressants (e.g., bupropion, SSRIs, venlafaxine, or certain MAOIs) do not potentiate alcohol, they can produce insomnia. To minimize this problem, the dose may be given earlier in the day. TCAs may cause episodes of excitement (rare), confusion, or mania, usually in patients with an underlying psychotic illness, suggesting that a preexisting disorder must be present for these drugs to exert any psychotomimetic effects. 

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