Pharmacotherapy of target symptoms in autistic spectrum disorders

Abstract

There are no aetiologically-based treatments available to cure autism. Though psychotropics have a role in the management of some symptoms of autism, clinical trial evidence for the use of psychotropics is in its infancy and needs close monitoring. About half of the subjects with high functioning pervasive developmental disorders (PDDs) are currently reported to be on psychotropics (anti-depressants, stimulants and antipsychotics), with many of them being on anti-epileptic medication simultaneously. Despite this high level of psychotropic use, few studies exist investigating the pharmacokinetics, pharmacodynamics or side-effect profiles in this population. Multiprofessional and parent partnership is essential in managing autism and psychopharmacology should be used in conjunction with environmental manipulation, educational modification and/or behavioral management strategies. A symptomatic approach to managing the difficult behaviours associated with autism is recommended. Some symptoms of autism may bemedication responsive (hyperactivity, obsessions, rituals, inattention, tics, etc), while other symptoms may beresponsive to behavioural interventions, but may require medication (aggression, anxiety, depression, impulsivity, sleep difficulties, etc), and symptoms which needspecific skill remediation are usually nonresponsive to medication (deficits in academic, social or sport domains). The new atypical antipsychotics (such as risperidone, olanzapine, amisulpiride, quetiapine) and SSRIs are increasingly being used in autism, with encouraging results, but a risk-benefit ratio of pharmacotherapy is essential with due weight being given to the sideeffects of medication. Despite symptomatic improvement with medication, one should remain cautious about longterm use of psychotropics. It is also important to recognize that psychotropics can sometimes worsen behaviour, and can produce iatrogenic symptoms. Certain anti-epileptic medication and psychotropic drugs are metabolized by the same cytochrome P450 isoenzymes in the liver. In such circumstances, the addition of a psychotropic agent may drastically alter the levels of the anti-epileptic medication and vice versa. It is suggested that specialist clinics should be involved when one is considering complex medication regimes, experimental drugs, polypharmacy, or if patients show unusual side-effects or is drug resistant.