Some information presented within this Center of Excellence was created in collaboration with the California Department of State Hospitals (DSH). This includes that the content has been specifically aligned to the DSH’s medication guidelines (DSH Psychotropic Medication Operational Procedures, appended to DSH Policy Directive 3400). These medication guidelines are applicable only to the DSH settings and inclusion within this resource does not indicate that they must be followed in any non-DSH settings. The medication guidelines included in this resource are those of DSH and do not necessarily represent the views, policy(ies), and/or position(s) of the American Psychiatric Association (APA).
Fluphenazine Decanoate | |
Indication(s) | Schizophrenia |
Dosing available as prefilled syringes | Fluphenazine decanoate is directly drawn up from a 5 ml vial with a 25 mg/ml concentration that can be stored after each use and used until empty. |
Recommended loading doses | Initiate with 12.5-25 mg IM weekly for 3 weeks, give maintenance dose 2 weeks after the last loading dose. |
Recommended maintenance dose | Most patients will be well maintained on a fluphenazine decanoate dose of 12.5 to 75 mg IM every two weeks. Therapeutic drug monitoring (TDM) can guide dosing. A trough fluphenazine plasma level between 1 and 4 ng/ml is the recommended therapeutic target range. |
Oral overlap | Not recommended if using loading doses. Without loading doses, overlap of a decreasing oral dose may need to continue for up to 4-6 weeks. |
Drug metabolizing enzyme | CYP2D6 |
Establishing tolerability | Prior to initiating fluphenazine decanoate, establish tolerability with either oral or immediate-release IM fluphenazine in fluphenazine-naïve patients. Use anticholinergic medications only to rescue acute dystonia or parkinsonism, treat ongoing dystonia or parkinsonism with amantadine. |
Storage | Room temperature |
Reconstitution or mixing | N/A |
Injection site | Deltoid or gluteal injections are both possible; the site can be chosen based on patient preference and body habitus. Alternate sites and use 1-inch needle for deltoid, 2-inch needle for gluteal injection. Give by deep intramuscular injection and use the Z-track technique to avoid leakage. |
Injection interval | Fluphenazine decanoate is typically given IM every 2 weeks; there is, however, flexibility around the injection interval and injections up to every 6 weeks have been used. |
Preparation | As this is a sesame oil vehicle, it may be pulled out of vial with a larger gauge needle (i.e. 18 gauge) then injected with a new, smaller gauge needle (i.e. 21 gauge) for patient comfort. |
Administration considerations | Fluphenazine decanoate is oil-based (sesame oil) which is more painful than water-based long-acting injectables. You also will need to push harder. Avoid giving more than 3 cc as a single injection. Therapeutic drug monitoring (TDM) can guide dosing. A trough fluphenazine plasma level between 1 and 4 ng/ml is a therapeutic target range. |
When a dose is missed | For those patients who are scheduled to receive fluphenazine decanoate injections every 2 or 3 weeks, if between 4-6 weeks from last dose, give maintenance dose. If > 6 weeks return to prior loading schedule. For those patients who are scheduled to receive fluphenazine decanoate injections every 4 weeks and who have received at least 2 previous injections as scheduled, the next dose should be administered not later than 8 weeks after the last injection. |
REMS | No |
Additional information | Sesame oil base - check for sesame allergy. |
Dose Conversion of Oral Fluphenazine to Fluphenazine Decanoate LAI | |
Oral Dose - Fluphenazine | LAI/IM Dose - Fluphenazine Decanoate |
Initial LAI Loading Dose | Suggested 12.5-25 mg weekly x 3 weeks |
Maintenance LAI Dose | Most patients will be well maintained on a fluphenazine decanoate dose of 12.5 to 75 mg IM every 2 weeks Overall dose range can be between 12.5-75 mg every 2 weeks, max dosing 75 mg/week Dose should be adjusted per fluphenazine trough plasma concentration |
10mg Daily | ~ 12.5 mg (0.5 ml) every 2 weeks |
20 mg Daily | ~ 25 mg (1 ml) every 2 weeks |
30 mg Daily | ~ 37.5 mg (1.5 ml) every 2 weeks |
40 mg Daily | ~ 50 mg (2 ml) every 2 weeks |
Recommended available dose formulations include 25mg/ml strength, in 5ml multiple does vials. Dose reduction may be necessary for CYP450 interactions or side effect intolerance. References: 1. APP Pharmaceuticals. (2010). Fluphenazine decanoate, injection usp. 2. American Psychiatric Association. (2020). The American Psychiatric Association Practice Guideline for the Treatment of Patients With Schizophrenia. American Psychiatric Association Publishing. https://doi.org/10.1176/appi.books.9780890424841 3. Meyer, Jonathan M., and Stephen M. Stahl. The clinical use of antipsychotic plasma levels: stahl's handbooks. Cambridge University Press, 2021. 4. DSH Medication Protocols. (2025). Chapter 9 | |
Practical issues (including administration)
For more information, download this fact sheet developed by the DSH Psychopharmacology Resource Network (PRN).
FDA Medication Label
Information on this topic is found in the FDA medication label. Not all information in the FDA medication label is included here, and clinicians should read the entire FDA medication label before making treatment decisions.
Prescribing should always be informed by the FDA medication label. Medication labels can be found by searching Drugs@FDA at the FDA website. Labels are also available using the Drugs@FDA app for Apple or Android devices.
Labels change over time, and the current label should always be consulted. Here is the most recent label, at time of writing.