affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.neostigmineMonitor Closely (1)neostigmine increases and amitriptyline decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.netupitant/palonosetronSerious - Use Alternative (1)netupitant/palonosetron, amitriptyline. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.nevirapineMinor (1)nevirapine will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.nicardipineMonitor Closely (1)nicardipine will increase the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.nifedipineMonitor Closely (1)nifedipine will decrease the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Minor (1)nifedipine will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.nilotinibSerious - Use Alternative (1)amitriptyline and nilotinib both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)nilotinib will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.norepinephrineMonitor Closely (3)amitriptyline increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. chlordiazepoxide increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. amitriptyline increases effects of norepinephrine by unknown mechanism. Use Caution/Monitor.Serious - Use Alternative (1)amitriptyline, norepinephrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.nortriptylineMonitor Closely (3)amitriptyline and nortriptyline both increase sedation. Use Caution/Monitor. chlordiazepoxide and nortriptyline both increase sedation. Use Caution/Monitor. amitriptyline and nortriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.Serious - Use Alternative (2)amitriptyline and nortriptyline both increase serotonin levels. Avoid or Use Alternate Drug. amitriptyline and nortriptyline both increase QTc interval. Avoid or Use Alternate Drug.octreotideSerious - Use Alternative (1)amitriptyline and octreotide both increase QTc interval. Avoid or Use Alternate Drug.octreotide (Antidote)Serious - Use Alternative (1)amitriptyline and octreotide (Antidote) both increase QTc interval. Avoid or Use Alternate Drug.ofloxacinMonitor Closely (1)amitriptyline and ofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.Minor (1)ofloxacin increases levels of chlordiazepoxide by decreasing metabolism. Minor/Significance Unknown.olanzapineMonitor Closely (3)chlordiazepoxide and olanzapine both increase sedation. Use Caution/Monitor. olanzapine and amitriptyline both increase QTc interval. Use Caution/Monitor. olanzapine and amitriptyline both increase sedation. Use Caution/Monitor.oliceridineMonitor Closely (3)amitriptyline, oliceridine. Either increases effects of the other by serotonin levels. Modify Therapy/Monitor Closely. amitriptyline increases toxicity of oliceridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Monitor for signs of urinary retention or reduced gastric motility if oliceridine is coadministered with anticholinergics. oliceridine, chlordiazepoxide. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.olodaterol inhaledMonitor Closely (1)amitriptyline and olodaterol inhaled both increase QTc interval. Use Caution/Monitor. TCAs prolong the QTc interval and may potentiate the effects of beta2 agonists on the cardiovascular system; increased risk of ventricular arrhythmiasolopatadine intranasalSerious - Use Alternative (2)chlordiazepoxide and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment. amitriptyline and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment. omeprazoleMinor (1)omeprazole increases levels of chlordiazepoxide by decreasing metabolism. Minor/Significance Unknown.onabotulinumtoxinAMonitor Closely (1)onabotulinumtoxinA and amitriptyline both decrease cholinergic effects/transmission. Modify Therapy/Monitor Closely.ondansetronSerious - Use Alternative (2)amitriptyline and ondansetron both increase QTc interval. Avoid or Use Alternate Drug. Avoid with congenital long QT syndrome; ECG monitoring recommended with concomitant medications that prolong QT interval, electrolyte abnormalities, CHF, or bradyarrhythmias. ondansetron, amitriptyline. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.opium tinctureMonitor Closely (2)chlordiazepoxide and opium tincture both increase sedation. Use Caution/Monitor. opium tincture and amitriptyline both increase sedation. Use Caution/Monitor.orphenadrineMonitor Closely (3)amitriptyline and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor. chlordiazepoxide and orphenadrine both increase sedation. Use Caution/Monitor. orphenadrine and amitriptyline both increase sedation. Use Caution/Monitor.osilodrostatMonitor Closely (1)osilodrostat and amitriptyline both increase QTc interval. Use Caution/Monitor.osimertinibMonitor Closely (1)osimertinib and amitriptyline both increase QTc interval. Use Caution/Monitor. Conduct periodic monitoring with ECGs and electrolytes in patients taking drugs known to prolong the QTc interval.oxaliplatinMonitor Closely (1)oxaliplatin will increase the level or effect of amitriptyline by Other (see comment). Use Caution/Monitor. Monitor for ECG changes if therapy is initiated in patients with drugs known to prolong QT interval.oxazepamMonitor Closely (2)chlordiazepoxide and oxazepam both increase sedation. Use Caution/Monitor. oxazepam and amitriptyline both increase sedation. Use Caution/Monitor.oxcarbazepineMinor (2)oxcarbazepine will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown. oxcarbazepine will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.oxybutyninMonitor Closely (1)oxybutynin and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.oxybutynin topicalMonitor Closely (1)oxybutynin topical and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.oxybutynin transdermalMonitor Closely (1)oxybutynin transdermal and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.oxycodoneMonitor Closely (2)oxycodone and amitriptyline both increase sedation. Use Caution/Monitor. chlordiazepoxide and oxycodone both increase sedation. Use Caution/Monitor.oxymetazoline intranasalMonitor Closely (1)amitriptyline increases effects of oxymetazoline intranasal by pharmacodynamic synergism. Use Caution/Monitor. TCAs inhibit norepinephrine uptake in adrenergic neurons, thereby increasing synaptic norepinephrine levels. Coadministration with alpha1 agonists may cause increased adrenergic receptor stimulation. When oxymetazoline is combined with intranasal tetracaine for dental anesthesia, avoid or use alternant anesthetic in patients taking TCAs.oxymorphoneMonitor Closely (2)oxymorphone and amitriptyline both increase sedation. Use Caution/Monitor. chlordiazepoxide and oxymorphone both increase sedation. Use Caution/Monitor.ozanimodMonitor Closely (1)ozanimod and amitriptyline both increase QTc interval. Modify Therapy/Monitor Closely. The potential additive effects on heart rate, treatment with ozanimod should generally not be initiated in patients who are concurrently treated with QT prolonging drugs with known arrhythmogenic properties.Serious - Use Alternative (1)ozanimod increases toxicity of amitriptyline by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Because the active metabolite of ozanimod inhibits MAO-B in vitro, there is a potential for serious adverse reactions, including hypertensive crisis. Therefore, coadministration of ozanimod with drugs that can increase norepinephrine or serotonin is not recommended. Monitor for hypertension with concomitant use.paliperidoneMonitor Closely (3)amitriptyline and paliperidone both increase QTc interval. Modify Therapy/Monitor Closely. chlordiazepoxide and paliperidone both increase sedation. Use Caution/Monitor. paliperidone and amitriptyline both increase sedation. Use Caution/Monitor.palonosetronSerious - Use Alternative (1)palonosetron, amitriptyline. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug.panax ginsengMinor (1)panax ginseng increases effects of amitriptyline by pharmacodynamic synergism. Minor/Significance Unknown.pancuroniumMonitor Closely (1)pancuronium and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.papaveretumMonitor Closely (2)chlordiazepoxide and papaveretum both increase sedation. Use Caution/Monitor. papaveretum and amitriptyline both increase sedation. Use Caution/Monitor.papaverineMonitor Closely (2)amitriptyline and papaverine both increase sedation. Use Caution/Monitor. chlordiazepoxide and papaverine both increase sedation. Use Caution/Monitor.parecoxibMinor (1)parecoxib will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.paroxetineMonitor Closely (1)amitriptyline and paroxetine both increase QTc interval. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)paroxetine and amitriptyline both increase serotonin levels. Avoid or Use Alternate Drug.pasireotideMonitor Closely (1)amitriptyline and pasireotide both increase QTc interval. Modify Therapy/Monitor Closely.pazopanibMonitor Closely (1)amitriptyline and pazopanib both increase QTc interval. Use Caution/Monitor.peginterferon alfa 2bMonitor Closely (1)peginterferon alfa 2b, amitriptyline. Other (see comment). Use Caution/Monitor. Comment: When patients are administered peginterferon alpha-2b with CYP2D6 substrates, the therapeutic effect of these drugs may be altered. Peginterferon alpha-2b may increase or decrease levels of CYP2D6 substrate.pentamidineContraindicated (1)amitriptyline and pentamidine both increase QTc interval. Contraindicated.pentazocineMonitor Closely (3)chlordiazepoxide and pentazocine both increase sedation. Use Caution/Monitor. amitriptyline and pentazocine both increase serotonin levels. Modify Therapy/Monitor Closely. pentazocine and amitriptyline both increase sedation. Use Caution/Monitor.pentobarbitalMonitor Closely (4)pentobarbital will decrease the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. pentobarbital will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. pentobarbital and amitriptyline both increase sedation. Use Caution/Monitor. pentobarbital and chlordiazepoxide both increase sedation. Use Caution/Monitor.Minor (1)pentobarbital, amitriptyline. Other (see comment). Minor/Significance Unknown. Comment: Barbiturates may increase adverse effects, including respiratory depression, produced by toxic doses of TCAs. With therapeutic doses of TCAs, barbiturates increase metabolism and decrease blood concentrations of TCAs.perampanelMonitor Closely (1)perampanel and chlordiazepoxide both increase sedation. Use Caution/Monitor.perphenazineMonitor Closely (2)perphenazine and amitriptyline both increase sedation. Use Caution/Monitor. chlordiazepoxide and perphenazine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)perphenazine and amitriptyline both increase QTc interval. Avoid or Use Alternate Drug.Minor (2)amitriptyline, perphenazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects. amitriptyline, perphenazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.phendimetrazineMonitor Closely (2)chlordiazepoxide increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. amitriptyline increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)amitriptyline, phendimetrazine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.phenelzineContraindicated (1)phenelzine and amitriptyline both increase serotonin levels. Contraindicated.phenobarbitalMonitor Closely (6)phenobarbital will decrease the level or effect of chlordiazepoxide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. phenobarbital will decrease the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. phenobarbital will decrease the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. phenobarbital will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. phenobarbital and chlordiazepoxide both increase sedation. Use Caution/Monitor. phenobarbital and amitriptyline both increase sedation. Use Caution/Monitor.Minor (1)phenobarbital, amitriptyline. Other (see comment). Minor/Significance Unknown. Comment: Barbiturates may increase adverse effects, including respiratory depression, produced by toxic doses of TCAs. With therapeutic doses of TCAs, barbiturates increase metabolism and decrease blood concentrations of TCAs.phentermineMonitor Closely (2)amitriptyline increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. chlordiazepoxide increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)amitriptyline, phentermine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.phenylephrineMonitor Closely (2)amitriptyline increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. chlordiazepoxide increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)amitriptyline, phenylephrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.phenylephrine ophthalmicMonitor Closely (1)amitriptyline, phenylephrine ophthalmic. Other (see comment). Use Caution/Monitor. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.phenylephrine POMonitor Closely (1)amitriptyline increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .Serious - Use Alternative (1)amitriptyline, phenylephrine PO. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.phenytoinMonitor Closely (3)phenytoin will decrease the level or effect of chlordiazepoxide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. phenytoin will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor therapeutic efficacy of amitriptyline; an increased dose may be required. Serum phenytoin levels should be obtained when tricyclic antidepressant agents are added to therapy due to the potential for impaired phenytoin metabolism and decreased seizure threshold. Tricyclic antidepressants when given concomitantly with anticonvulsants can increase CNS depression. phenytoin will decrease the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor therapeutic efficacy of amitriptyline; an increased dose may be required. Serum phenytoin levels should be obtained when tricyclic antidepressant agents are added to therapy due to the potential for impaired phenytoin metabolism and decreased seizure threshold. Tricyclic antidepressants when given concomitantly with anticonvulsants can increase CNS depression.pholcodineMonitor Closely (2)amitriptyline and pholcodine both increase sedation. Use Caution/Monitor. chlordiazepoxide and pholcodine both increase sedation. Use Caution/Monitor.physostigmineMonitor Closely (1)physostigmine increases and amitriptyline