Long Acting Injectable: Haloperidol Decanoate (PART 2)

 

PART 1 is available here:

Haloperidol Decanoate (PART 1)

 


This part will focus on loading and conversion strategies for haloperidol decanoate. 

 

HOW MUCH MONTHLY MEDICATION IS NEEDED?

Oral haloperidol bioavailability = 65%.

Patient on 10 mg/day haloperidol will have total medication exposure of =

10mg/day X 30 days X 65% = 195 mg/month ~ 200 mg/4 weekly dose.

 

Source: CNS Spectrums, Volume 22,Supplement S1 (CME SUPPLEMENT)December 2017 , pp. 14-28

 


HOW TO INITIATE LOADING DOSE ?

(OPTION 1): TWO LOADING DOSE STRATEGY WITH NO ORAL MEDICATION

  • Loading dose of ~ 20 times the oral maintenance dose in DIVIDED injections during the FIRST TWO WEEKS of conversion to depot medication.

  • The dose of haloperidol decanoate is gradually reduced, dropping to about ten times the oral dose in the third and fourth months.

  • No supplemental oral medication was used.

Source: Hosp Community Psychiatry. 1993 Dec;44(12):1155-61.

 


(OPTION 2): WEEKLY TAPER STRATEGY

  • Treat with oral haloperidol for 6 weeks and then switch to decanoate.

  • Haloperidol decanoate 100 mg qweekly X 4 weeks –> q2weekly X 4 weeks –> q4weekly.

  • During this first 2weeks: Oral Haloperidol coverage of 5 mg/day may be needed during first 2 weeks, as this strategy provided coverage equal to 10 mg/day after the third week. 

  • By the third week, mean plasma haloperidol concentrations from the decanoate injections were comparable with those of the 10-mg oral haloperidol treatment (7.95 +/- 4.94 ng/mL vs. 7.79 +/- 4.79 ng/mL).

Source: J Clin Psychiatry. 1996 Jul;57(7):298-302.

 


HOW LONG TO CONTINUE ORAL HALOPERIDOL AFTER DECANOATE INJECTION?

At least 1-2 months, as it can take 3 to 5 doses of decanoate before steady state is reached.

 

Source: Psychopharrnacol 1989; 98:433–439.

 


I will be thankful if member’s can share their experiences and/or useful articles on these topics of (a) loading dose strategy and (b) length of duration of oral haloperidol after decanoate injection. Thanks. 

Dr. Harvinder Singh, M.D. (Admin)


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