antagonism. Use Caution/Monitor.risperidone increases effects of henbane by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.homatropinehomatropine decreases levels of risperidone by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.homatropine decreases levels of risperidone by pharmacodynamic antagonism. Use Caution/Monitor.risperidone increases effects of homatropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.hydromorphonehydromorphone and risperidone both increase sedation. Use Caution/Monitor.hydroxyzinehydroxyzine and risperidone both increase sedation. Use Caution/Monitor.hydroxyzine and risperidone both increase QTc interval. Use Caution/Monitor.hyoscyaminehyoscyamine decreases levels of risperidone by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.hyoscyamine decreases levels of risperidone by pharmacodynamic antagonism. Use Caution/Monitor.risperidone increases effects of hyoscyamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.hyoscyamine sprayrisperidone increases effects of hyoscyamine spray by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.hyoscyamine spray decreases levels of risperidone by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.hyoscyamine spray decreases levels of risperidone by pharmacodynamic antagonism. Use Caution/Monitor.iloperidoneiloperidone and risperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.iloperidone and risperidone both increase QTc interval. Use Caution/Monitor.iloperidone and risperidone both increase sedation. Use Caution/Monitor.imipramineimipramine and risperidone both increase QTc interval. Modify Therapy/Monitor Closely.risperidone and imipramine both increase sedation. Use Caution/Monitor.incobotulinumtoxinArisperidone, incobotulinumtoxinA. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects.indacaterol, inhaledindacaterol, inhaled, risperidone. QTc interval. Use Caution/Monitor. Drugs that are known to prolong the QTc interval may have an increased the risk of ventricular arrhythmias.indinavirindinavir will increase the level or effect of risperidone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.insulin aspartrisperidone, insulin aspart. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.insulin degludecrisperidone decreases effects of insulin degludec by Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; dose of antidiabetic agents may need adjustment and increased frequency of glucose monitoring may be required.insulin degludec/insulin aspartrisperidone decreases effects of insulin degludec/insulin aspart by Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; dose of antidiabetic agents may need adjustment and increased frequency of glucose monitoring may be required.insulin detemirrisperidone, insulin detemir. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.insulin glarginerisperidone, insulin glargine. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.insulin glulisinerisperidone, insulin glulisine. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.insulin inhaledrisperidone decreases effects of insulin inhaled by Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; dose of antidiabetic agents may need adjustment and increased frequency of glucose monitoring may be required.insulin lisprorisperidone, insulin lispro. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.insulin NPHrisperidone, insulin NPH. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.insulin regular humanrisperidone, insulin regular human. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.ipratropiumrisperidone increases effects of ipratropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.isavuconazonium sulfaterisperidone will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.isoproterenolrisperidone increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.istradefyllineistradefylline will increase the level or effect of risperidone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of P-gp substrates in clinical trials. Consider dose reduction of sensitive P-gp substrates.itraconazoleitraconazole will increase the level or effect of risperidone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.itraconazole and risperidone both increase QTc interval. Use Caution/Monitor.ivacaftorivacaftor increases levels of risperidone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Ivacaftor and its M1 metabolite has the potential to inhibit P-gp; may significantly increase systemic exposure to sensitive P-gp substrates with a narrow therapeutic index.risperidone increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor when coadministered with weak CYP3A4 inhibitors .ketoconazoleketoconazole will increase the level or effect of risperidone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.ketoconazole and risperidone both increase QTc interval. Modify Therapy/Monitor Closely.ketotifen, ophthalmicrisperidone and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.lapatiniblapatinib and risperidone both increase QTc interval. Use Caution/Monitor.lasmiditanlasmiditan, risperidone. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.lemborexantrisperidone will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Lower nightly dose of lemborexant recommended if coadministered with weak CYP3A4 inhibitors. See drug monograph for specific dosage modification.lemborexant, risperidone. Either increases effects of the other by sedation. Modify Therapy/Monitor Closely. Dosage adjustment may be necessary if lemborexant is coadministered with other CNS depressants because of potentially additive effects.letermovirletermovir increases levels of risperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.levalbuterolrisperidone increases and levalbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.levofloxacinlevofloxacin and risperidone both increase QTc interval. Use Caution/Monitor.levoketoconazolelevoketoconazole and risperidone both increase QTc interval. Modify Therapy/Monitor Closely.levoketoconazole will increase the level or effect of risperidone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.levomilnacipranlevomilnacipran, risperidone. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).levorphanollevorphanol and risperidone both increase sedation. Use Caution/Monitor.linezolidlinezolid, risperidone. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).liraglutiderisperidone, liraglutide. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.lisdexamfetaminerisperidone increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.lithiumlithium, risperidone. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).lithium and risperidone both increase QTc interval. Use Caution/Monitor.lofepraminelofepramine and risperidone both increase QTc interval. Modify Therapy/Monitor Closely.risperidone and lofepramine both increase sedation. Use Caution/Monitor.lofexidinerisperidone and lofexidine both increase sedation. Use Caution/Monitor.lomitapiderisperidone increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.lonafarniblonafarnib will increase the level or effect of risperidone by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Lonafarnib is a weak P-gp inhibitor. Monitor for adverse reactions if coadministered with P-gp substrates where minimal concentration changes may lead to serious or life-threatening toxicities. Reduce P-gp substrate dose if needed.loprazolamloprazolam and risperidone both increase sedation. Use Caution/Monitor.loratadineloratadine will increase the level or effect of risperidone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.lorazepamlorazepam and risperidone both increase sedation. Use Caution/Monitor.lorcaserinlorcaserin will increase the level or effect of risperidone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.lorcaserin, risperidone. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).lormetazepamlormetazepam and risperidone both increase sedation. Use Caution/Monitor.loxapineloxapine and risperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.loxapine and risperidone both increase sedation. Use Caution/Monitor.loxapine inhaledloxapine inhaled and risperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.loxapine inhaled and risperidone both increase sedation. Use Caution/Monitor.lumefantrinelumefantrine will increase the level or effect of risperidone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.lumefantrine and risperidone both increase QTc interval. Modify Therapy/Monitor Closely.lurasidonelurasidone, risperidone. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.maprotilinemaprotiline and risperidone both increase QTc interval. Modify Therapy/Monitor Closely.risperidone and maprotiline both increase sedation. Use Caution/Monitor.marijuanarisperidone and marijuana both increase sedation. Use Caution/Monitor.meclizinemeclizine decreases levels of risperidone by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.meclizine decreases levels of risperidone by pharmacodynamic antagonism. Use Caution/Monitor.risperidone increases effects of meclizine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.melatoninrisperidone and melatonin both increase sedation. Use Caution/Monitor.meperidinemeperidine and risperidone both increase sedation. Use Caution/Monitor.meperidine, risperidone. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).meprobamaterisperidone and meprobamate both increase sedation. Use Caution/Monitor.metaproterenolrisperidone increases and metaproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.metaxalonemetaxalone and risperidone both increase sedation. Use Caution/Monitor.metforminrisperidone, metformin. Other (see comment). Use Caution/Monitor. Comment: Atypical antipsychotics have been associated with hyperglycemia that may alter blood glucose control; monitor glucose levels closely.methadonemethadone and risperidone both increase QTc interval. Use Caution/Monitor.methadone and risperidone both increase sedation. Use Caution/Monitor.methadone, risperidone. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).methamphetaminerisperidone increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.methocarbamolmethocarbamol and risperidone both increase sedation. Use Caution/Monitor.methscopolaminemethscopolamine decreases levels of risperidone by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.methscopolamine decreases levels of risperidone by pharmacodynamic antagonism. Use Caution/Monitor.risperidone increases effects of methscopolamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.methylenedioxymethamphetaminerisperidone increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.methylergonovinemethylergonovine, risperidone. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).methylphenidaterisperidone increases toxicity of methylphenidate by pharmacodynamic antagonism. Use Caution/Monitor. Closely monitor for signs of altered clinical response to either methylphenidate or an antipsychotic when using these drugs in combination.methylphenidate transdermalmethylphenidate transdermal will increase the level or effect of risperidone by unspecified interaction mechanism. Use Caution/Monitor. When coadministered with methylphenidate, changes in dosage of either or both medications, may increase the risk of extrapyramidal symptoms (EPS). Monitor for signs of EPS.metoclopramiderisperidone and metoclopramide both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.midazolammidazolam and risperidone both increase sedation. Use Caution/Monitor.midazolam intranasalrisperidone will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation.midazolam intranasal, risperidone. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or