August 2007

Lithium and the Risk of Alzheimer's
Lithium treatment may decrease the risk of Alzheimer's disease in patients with bipolar disorder.

T3 Augments SSRI Treatment
Adding triiodothyronine (T3) to sertraline (Zoloft and others) treatment increased response and remission rates in depressed patients.

Adding Atomoxetine to an SSRI: A Negative Study
Adding atomoxetine (Strattera) to sertraline (Zoloft and others) did not increase remission rates for depressed patients who responded incompletely to the antidepressant alone.

A Tale of Two Interactions
Quetiapine (Seroquel and others) can raise levels of r-methadone, and carbamazepine (Tegretol and others) can lower levels of aripiprazole (Abilify).

Risperidone and Prolactin in Young Patients
Prolactin levels increased in children and adolescents treated with risperidone (Risperdal) for pervasive development disorder.

In Brief
Topiramate and Cognitive Impairment in Children; Brain Structure Abnormalities in Pedophiles

More on Antidepressants and Suicide
A meta-analysis of studies of children and adolescents with depression, obsessive compulsive disorder, or anxiety disorders found a small increased risk of suicidal ideation/suicide attempt, but no completed suicides.

Risperidone and Prolactin in Young Patients

August 2007

The US Food and Drug Administration recently approved another indication for risperidone (Risperdal)—the treatment of autism in children. Along with other antipsychotics, risperidone is increasingly used in children and adolescents for many diagnoses. As in adults, there is concern with antipsychotics about weight gain and metabolic effects, which may be greater in young patients. As well, children are at risk for hyperprolactinemia, associated with the first generation of antipsychotics and risperidone.

Troost et al observe that the prolactin-raising effects of antipsychotics may be greater in children and adolescents than in older people.1 When children are treated with risperidone, prolactin increases two- to fourfold.1 The authors prospectively studied the short- and long-term effects of risperidone on prolactin levels in children and adolescents.

Twenty-five subjects aged 5 to 15 years with pervasive development disorder were treated with risperidone, 0.5 to 6 mg/day, based on age, weight, and clinical response. The average serum prolactin increased fourfold after 8 weeks of treatment with risperidone, and 19 of the subjects (76%) had prolactin levels higher than the upper limit of normal. There was a slight decrease in prolactin in week 24, but it remained markedly elevated. Children who were genetically rapid metabolizers using the cytochrome P450 2D6 isoenzyme had higher levels of the active metabolite 9-hydroxy-risperidone and higher plasma prolactin levels.

As in all clinical medicine, risks of treatments must be balanced against potential benefits. For children and adolescents, hyperprolactinemia must be considered among the possible adverse effects of antipsychotics. Short-term effects of elevated prolactin can include decreased libido, decreased menstruation, and gynecomastia. Long-term effects are uncertain. This study suggests risperidone's effect on prolactin levels is likely to persist over time, but a study we described in June (BTP 2007;30:25) found that prolactin levels that were initially elevated in adults treated with risperidone returned almost to baseline over 5 years.2

1Troost PW, Lahuis BE, Hermans MH, Buitelaar JK, van Engeland H, Scahill L, Minderaa RB, Hoekstra PJ: Prolactin release in children treated with risperidone: Impact and role of CYP2D6 metabolism. J Clin Psychopharmacol 2007;27:52-57.

2Eberhard J, Lindström E, Holstad M, Levander S: Prolactin level during 5 years of risperidone treatment in patients with psychotic disorders. Acta Psychiatr Scand 2007;115:268-276.