Understanding Perseris and Its Route of Administration
Perseris is an extended-release injectable suspension of risperidone, a second-generation (atypical) antipsychotic medication used for the treatment of schizophrenia in adults [1.3.5]. A critical point of clarification for healthcare professionals is its administration route. The U.S. Food and Drug Administration (FDA) and official prescribing information definitively state that Perseris is for subcutaneous (subq) injection only [1.2.1, 1.2.6]. It must not be administered by any other route, including intramuscularly (IM).
This medication is designed to be given by a healthcare provider once a month [1.9.1]. The injection sites are specific to the subcutaneous layer of tissue, which is the fatty tissue just beneath the skin. The recommended injection sites are the abdomen or the back of the upper arm [1.3.1]. To minimize irritation, injection sites should be rotated with each monthly dose [1.2.2].
How Perseris Works
The therapeutic effects of Perseris are believed to come from its activity as a dopamine Type 2 (D2) and serotonin Type 2A (5-HT2A) receptor antagonist [1.4.1]. After subcutaneous injection, the liquid medication, which uses the Atrigel delivery system, comes into contact with bodily fluids and forms a solid depot [1.2.2, 1.5.3]. This depot allows for the continuous release of risperidone over the entire one-month dosing period, ensuring stable plasma concentrations of the medication without the need for daily oral pills [1.2.2]. The initial doses are 90 mg or 120 mg, which correspond to daily oral risperidone doses of 3 mg and 4 mg, respectively [1.9.1].
Step-by-Step Subcutaneous Administration by a Healthcare Professional
Administering Perseris requires careful preparation and technique to ensure the dose is delivered correctly into the subcutaneous tissue and to avoid accidental intramuscular injection [1.2.5].
- Preparation: The medication kit should be brought to room temperature for at least 15 minutes before mixing [1.2.1]. The kit contains two syringes—one with risperidone powder and one with the liquid delivery system—which must be mixed by the healthcare professional immediately before administration [1.3.1].
- Mixing: The contents are passed back and forth between the two connected syringes for a specific number of cycles to ensure a uniform suspension [1.3.1].
- Site Selection: An appropriate injection site on the abdomen or back of the upper arm with adequate subcutaneous tissue is selected. The area should be clean and free of irritation, scarring, or nodules [1.2.6].
- Injection: The skin at the injection site is pinched to lift the adipose tissue away from the underlying muscle [1.2.5]. The 18-gauge, 5/8-inch needle is inserted fully into the subcutaneous tissue, and the medication is injected slowly and steadily [1.2.3, 1.2.5].
- Post-Injection: The needle is withdrawn, and the safety guard is activated. The area should not be rubbed or massaged [1.3.3]. A small lump may be present at the injection site for several weeks, which will decrease in size over time [1.3.1].
Comparison: Perseris (Subcutaneous) vs. Risperdal Consta (Intramuscular)
Both Perseris and Risperdal Consta are long-acting injectable forms of risperidone, but they differ significantly in their administration route, frequency, and formulation [1.5.1].
| Feature | Perseris (risperidone) | Risperdal Consta (risperidone) |
|---|---|---|
| Administration Route | Subcutaneous (Subq) in the abdomen or upper arm [1.2.2] | Intramuscular (IM) in the deltoid or gluteal muscle [1.4.4] |
| Dosing Frequency | Once-monthly [1.9.1] | Every 2 weeks [1.3.6] |
| Formulation | Liquid suspension forms an in-situ solid depot [1.2.2] | Microsphere-based suspension [1.4.4] |
| Oral Supplementation | Not recommended [1.9.1] | Required for the first 3 weeks after the initial injection [1.4.4] |
| Indication | Schizophrenia in adults [1.3.5] | Schizophrenia and as monotherapy or adjunctive therapy for Bipolar I Disorder in adults [1.5.2, 1.3.6] |
Advantages of Subcutaneous vs. Intramuscular Injections
Subcutaneous injections, like Perseris, are delivered into the fatty tissue, which has fewer blood vessels than muscle. This typically results in slower, more sustained absorption of the medication over time [1.6.1]. Subcutaneous injections generally use smaller needles and are often considered less painful than IM injections [1.6.2, 1.6.5]. In contrast, IM injections allow for quicker absorption due to the muscle's rich blood supply, which is necessary for some medications but can also lead to more pronounced peaks and troughs in drug levels [1.6.3, 1.6.5].
Important Safety Considerations and Side Effects
Before starting Perseris, tolerability should be established with oral risperidone [1.3.1]. Perseris carries a boxed warning for increased mortality in elderly patients with dementia-related psychosis and is not approved for this use [1.2.4].
Common side effects (≥5%) can include [1.8.2]:
- Weight gain
- Sedation/somnolence
- Constipation
- Musculoskeletal pain
- Akathisia (restlessness)
- Anxiety
- Injection site reactions like pain and redness (erythema)
Serious side effects associated with atypical antipsychotics include Neuroleptic Malignant Syndrome (NMS), Tardive Dyskinesia (TD), and metabolic changes like hyperglycemia, dyslipidemia, and weight gain [1.3.2]. Patients should be monitored regularly for these potential effects [1.8.2].
Conclusion
Perseris is exclusively a subcutaneous (subq) injection administered once-monthly by a healthcare provider for the treatment of schizophrenia in adults [1.2.1]. Its route of administration into the fatty tissue of the abdomen or upper arm distinguishes it from intramuscular (IM) injections like Risperdal Consta. This delivery method provides a slow, sustained release of risperidone over a month, offering a valuable therapeutic option that can help improve treatment adherence [1.2.2, 1.7.5]. Understanding the correct preparation, administration technique, and potential side effects is crucial for healthcare providers to ensure patient safety and efficacy.
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Consult with a qualified healthcare professional for any medical concerns or before making any decisions related to your health or treatment.
