There are currently seven second generation, or atypical, antipsychotics approved for use in children and adolescents. These include risperidone (irritability associated with autism, schizophrenia, bipolar disorder), aripiprazole (irritability associated with autism, schizophrenia, bipolar disorder), quetiapine (schizophrenia and bipolar disorder), olanzapine (schizophrenia and bipolar disorder), lurasidone (schizophrenia and bipolar disorder), paliperidone (schizophrenia), and asenapine (bipolar disorder).
The child or adolescent with schizophrenia or bipolar disorder is typically having medications managed by a psychiatric provider. However, children with autism spectrum disorder and major depressive disorder are often managed by primary care.
You may notice that augmentation of a SSRI medication with a second generation antipsychotic such as aripiprazole for major depression is not an FDA-approved use for adolescents. This use is only FDA approved for adults, so this would be off-label use, but also a reasonable strategy for augmenting treatment of depression in adolescent patients in the primary care clinic. I have found this to be helpful in adolescents who have partial benefit from SSRI or SNRI medication, but with residual symptoms of depression, especially irritability. A typical starting dose of aripiprazole for antidepressant augmentation is 1mg, which can be titrated to 2-5mg.
Both aripiprazole and risperidone can be quite helpful for managing behaviors and irritability in children with ASD. Aripiprazole can be started at 1mg daily, and titrated up to 5-10mg daily depending on tolerability. 1-2 mg is often a beneficial dose. Risperidone is started at 0.25mg daily, and titrated in increments of 0.25mg to max of 3mg total daily dose. Oftentimes 0.25mg BID is a beneficial dose.
The most common side effect from these two medications is weight gain. Also there is the risk of dyslipidemia and development of type 2 diabetes. Fasting lipids and glucose should be obtained at baseline, and again after three months of treatment, and every year thereafter. Weight should be checked at each appointment. Some psychiatrists obtain a baseline prolactin level prior to initiation of risperidone, though not necessarily the community standard of practice. The risk of gynocomastia should be discussed with the patient and guardian prior to initiation.
Extrapyramidal side effects are a risk with second generation antipsychotics. There continues to be a risk of tardive dyskinesia, though is relatively rare when compared with first generation antipsychotics. Second generation antipsychotics also carry the risk of dystonic reaction, akathisia, and rarely neuroleptic malignant syndrome.
EKG is not routinely obtained when starting aripiprazole or risperidone. This can be considered in a patient with a history of arrhythmia, or if used in combination with other potentially QT-prolonging medications (guanfacine/clonidine or stimulant medication, high dose (30-40mg) citalopram).
Another consideration with risperidone and aripiprazole specifically is their drug-drug interaction with fluoxetine (and paroxetine, though this is not routinely used in children). These SSRI medications inhibit the metabolism of both risperidone and aripiprazole, so lower starting doses are advised. Children with known deficiency of cytochrome 2D6 metabolism should start on lower doses as well.