Haloperidolinteractions

Drugs that Prolong QTc Interval: Avoid concomitant use with haloperidol decanoate injection. See full prescribing information for additional clinically significant drug interactions with haloperidol decanoate injection.

7.1 Drugs that

Prolong the QTc Interval Avoid concomitant use of haloperidol decanoate injection with other drugs with a known potential to prolong the QTc interval. If concomitant use cannot be avoided: Obtain ECGs when initiating and during concomitant use as clinically indicated. Obtain serum electrolytes (including potassium, calcium, phosphorus, and magnesium) when initiating and during concomitant use as clinically indicated. QTc interval prolongation has been observed with haloperidol decanoate injection treatment. Concomitant use of haloperidol decanoate injection with other products that prolong the QTc interval may result in a greater increase in the QTc interval, and adverse reactions associated with QTc interval prolongation, including torsade de pointes, other serious arrythmias, and sudden death.

7.2 Other Clinically

Significant Drug Interactions Table 3 describes other clinically significant drug interactions of haloperidol decanoate injection.

Table 3: Other Clinically Significant Drugs Interactions 1 CNS Depressants Clinical Impact Haloperidol may potentiate CNS depressants. Prevention or Management Avoid concomitant use of haloperidol decanoate injection with CNS depressants such as anesthetics, opioids, and alcohol. CYP3A4 and/or CYP2D6 Inhibitors Clinical Impact CYP3A4 and/or CYP2D6 inhibitors increase haloperidol exposure (haloperidol is a CYP3A4 and CYP2D6 substrate). Concomitant use of haloperidol decanoate injection and CYP3A4 and/or CYP2D6 inhibitors may increase the risk of haloperidol-associated adverse reactions. Prevention or Management Monitor for signs or symptoms of increased or prolonged pharmacologic effects of haloperidol. Decrease the dosage of haloperidol decanoate injection as clinically necessary. CYP3A4 Inducers Clinical Impact CYP3A4 inducers decrease haloperidol exposure (haloperidol is a CYP3A4 substrate). Concomitant use of haloperidol decanoate injection with CYP3A4 inducers may reduce the effectiveness of haloperidol decanoate injection. Prevention or Management Monitor patients and if necessary, increase the dosage of haloperidol decanoate injection. CYP2D6 Substrates Clinical Impact Haloperidol is a CYP2D6 inhibitor. Plasma concentrations of CYP2D6 substrates may increase when they are concomitantly administered with haloperidol decanoate injection. Prevention or Management Monitor plasma concentrations of the CYP2D6 substrate, if possible. Consider reducing the dosage of the CYP2D6 substrate, if necessary. Refer to the Prescribing Information of the CYP2D6 substrate. Dopaminergic Drugs Clinical Impact Haloperidol may antagonize the effects of levodopa, dopamine agonists, and other drugs intended to increase dopamine levels. Prevention or Management Haloperidol decanoate injection is contraindicated in patients with Parkinson's disease and dementia with Lewy bodies. For conditions other than Parkinson's disease and dementia with Lewy bodies, when possible, avoid concomitant use of haloperidol decanoate injection with dopaminergic drugs. Anticholinergic Drugs Clinical Impact The healthcare provider should keep in mind the possible increase in intraocular pressure when anticholinergic drugs are administered concomitantly with haloperidol decanoate injection. Prevention or Management Monitor and manage patients as clinically appropriate. Lithium Clinical Impact Concomitant use of haloperidol decanoate injection with lithium may cause an encephalopathic syndrome followed by irreversible brain damage. Prevention or Management Monitor patients who concomitantly use haloperidol decanoate injection with lithium closely for early signs of neurological toxicity, and discontinue haloperidol decanoate injection or both haloperidol decanoate injection and lithium promptly if such signs appear. 1 See www.fda.gov/CYPandTransporterInteractingDrugs for examples of CYP3A4 and/or CYP2D6 inhibitors, CYP3A4 inducers, and CYP2D6 substrates.