Aripiprazole in the Treatment of Psychoses
Aripiprazole is an atypical (second generation) antipsychotic primarily used in the short term treatment and maintenance of adult and adolescent schizophrenia. Aripiprazole may also be prescribed for the management of bipolar mania, major depressive disorder, autistic disorder, and Tourette’s syndrome.
Mechanism of Action
The mechanism by which aripiprazole exerts its effects is not completely understood, but it is known that the drug is a partial agonist for both D2 dopamine receptors and 5-HT1A serotonin receptors. Aripiprazole is also an antagonist for 5-HT2A serotonin receptors. This partial agonist/antagonist relationship is thought to be the reason for aripiprazole’s effectiveness in a wide range of psychiatric disorders.
Aripiprazole is administered orally once a day, with or without food. For adults, the initial and target dose is 10-15 mg/day. For adolescents, the initial dose begins around 2 mg/day and increases every two days to the target dose of 10 mg/day. Regardless of age, the maximum dose should not exceed 30 mg/day. Higher doses than 30 mg/day (adults) and 10 mg/day (adolescents) are not shown to increase the effectiveness of aripiprazole. It is important for a physical therapist to understand the dosing schedule of a patient’s medication. In the case of aripiprazole, a once-daily administration is easier to monitor compared to other medications. For more information regarding dosages in the treatment of disorders other than schizophrenia please visit the FDA’s medication guide for aripiprazole: Abilify (Aripiprazole).
The half-life of aripiprazole is approximately 75 hours, but the drug has a major metabolite (dehydro-aripiprazole) with similar affinities and a half-life of approximately 94 hours. One study found aripiprazole to have a clearance of 57.5 to 66.7 mL/min. Aripiprazole is eliminated by way of two hepatic P450 isoenzymes, and excreted via urine and feces. The extended effectiveness of aripiprazole and its major metabolite can be significant for a physical therapist when monitoring side effects, especially in patients that have recently decreased dosages or discontinued taking aripiprazole.
In addition to the common side effects of atypical antipsychotics, people taking aripiprazole may experience akathisias and tremors. Patients may also experience more serious extrapyramidal symptoms can also be experienced, most importantly neuroleptic malignant syndrome.
Physical Therapy Implications
It is important for a physical therapist to expect and be prepared for these adverse effects. A patient with akathisia could show increased restlessness when trying to perform certain therapies or modalities. Patients who suffer from somnolence could require special scheduling to work around their drowsiness, or at the very least will need to be watched more closely to prevent accidents in their drowsy state. Extrapyramidal symptoms require extra vigilance as some components may be irreversible or life-threatening. As with all patients suffering from psychotic disorders, physical therapists should monitor the patient’s mood or affect closely and adjust the treatment accordingly.
- ABILIFY (Aripiprazole) 2014. https://www.accessdata.fda.gov/drugsatfda_docs/label/2014/021436s038,021713s030,021729s022,021866s023lbl.pdf. Accessed September 12, 2018.
- Di Sciascio G, Riva MA. Aripiprazole: from pharmacological profile to clinical use. Neuropsychiatr Dis Treat. 2015;11:2635-47. Published 2015 Oct 13. doi:10.2147/NDT.S88117
- Mallikaarjun S; Salazar DE; Bramer SL Pharmacokinetics, tolerability, and safety of aripiprazole following multiple oral dosing in normal healthy volunteers. J. Clin. Pharmacol. 2004, 44, 179– 187, DOI: 10.1177/0091270003261901