Other (see comment). Use Caution/Monitor. Comment: Increased catecholamine receptor sensitivity; may increase CNS and cardiovascular effects, including arrhythmias.liothyronineliothyronine increases effects of amitriptyline by Other (see comment). Use Caution/Monitor. Comment: Increased catecholamine receptor sensitivity; may increase CNS and cardiovascular effects, including arrhythmias.liotrixliotrix increases effects of amitriptyline by Other (see comment). Use Caution/Monitor. Comment: Increased catecholamine receptor sensitivity; may increase CNS and cardiovascular effects, including arrhythmias.lisdexamfetamineamitriptyline increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.amitriptyline, lisdexamfetamine. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Initiate with lower doses and monitor for signs and symptoms of serotonin syndrome, particularly during initiation or dosage increase. If serotonin syndrome occurs, discontinue along with concomitant serotonergic drug(s).lithiumamitriptyline and lithium both increase serotonin levels. Modify Therapy/Monitor Closely.lithium and amitriptyline both increase QTc interval. Use Caution/Monitor.lofepramineamitriptyline and lofepramine both decrease cholinergic effects/transmission. Use Caution/Monitor.amitriptyline and lofepramine both increase sedation. Use Caution/Monitor.lofexidineamitriptyline and lofexidine both increase sedation. Use Caution/Monitor.amitriptyline decreases effects of lofexidine by unspecified interaction mechanism. Use Caution/Monitor.loprazolamloprazolam and amitriptyline both increase sedation. Use Caution/Monitor.loratadineloratadine will increase the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.lorazepamlorazepam and amitriptyline both increase sedation. Use Caution/Monitor.lorcaserinlorcaserin will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.lormetazepamlormetazepam and amitriptyline both increase sedation. Use Caution/Monitor.loxapineloxapine and amitriptyline both increase sedation. Use Caution/Monitor.loxapine inhaledloxapine inhaled and amitriptyline both increase sedation. Use Caution/Monitor.lsdamitriptyline and lsd both increase serotonin levels. Modify Therapy/Monitor Closely.lurasidonelurasidone increases effects of amitriptyline by Other (see comment). Use Caution/Monitor. Comment: Potential for increased risk of hypotension with concurrent use. Monitor blood pressure and adjust dose of antihypertensive agent as needed.lurasidone, amitriptyline. Either increases toxicity of the other by sedation. Use Caution/Monitor. Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.maprotilineamitriptyline and maprotiline both decrease cholinergic effects/transmission. Use Caution/Monitor.amitriptyline and maprotiline both increase sedation. Use Caution/Monitor.maravirocmaraviroc, amitriptyline. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of orthostatic hypotension.marijuanaamitriptyline and marijuana both increase sedation. Use Caution/Monitor.mavacamtenamitriptyline will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose. meclizinemeclizine and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.melatoninamitriptyline and melatonin both increase sedation. Use Caution/Monitor.meperidinemeperidine and amitriptyline both increase sedation. Use Caution/Monitor.meprobamateamitriptyline and meprobamate both increase sedation. Use Caution/Monitor.metaproterenolamitriptyline increases and metaproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.metaxalonemetaxalone and amitriptyline both increase sedation. Use Caution/Monitor.methadoneamitriptyline and methadone both increase QTc interval. Modify Therapy/Monitor Closely.methadone and amitriptyline both increase sedation. Use Caution/Monitor.methamphetamineamitriptyline increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.methocarbamolmethocarbamol and amitriptyline both increase sedation. Use Caution/Monitor.methscopolaminemethscopolamine and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.methylenedioxymethamphetamineamitriptyline increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.methylphenidateamitriptyline, methylphenidate. 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.methylphenidate transdermalmethylphenidate transdermal will increase the level or effect of amitriptyline by decreasing elimination. Modify Therapy/Monitor Closely. Consider decreasing the dose of these drugs when given coadministered with methylphenidate. Monitor for drug toxiticities when initiating or discontinuing methylphenidate. midazolammidazolam and amitriptyline both increase sedation. Use Caution/Monitor.midazolam intranasalmidazolam intranasal, amitriptyline. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.midodrineamitriptyline increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.mifepristonemifepristone, amitriptyline. QTc interval. Modify Therapy/Monitor Closely. Use alternatives if available.mipomersenmipomersen, amitriptyline. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.mirabegronmirabegron will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.mirtazapineamitriptyline and mirtazapine both increase sedation. Use Caution/Monitor.amitriptyline and mirtazapine both increase serotonin levels. Modify Therapy/Monitor Closely.modafinilmodafinil will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.amitriptyline increases and modafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.morphinemorphine and amitriptyline both increase sedation. Use Caution/Monitor.amitriptyline and morphine both increase serotonin levels. Modify Therapy/Monitor Closely.motherwortamitriptyline and motherwort both increase sedation. Use Caution/Monitor.moxonidineamitriptyline and moxonidine both increase sedation. Use Caution/Monitor.nabiloneamitriptyline and nabilone both increase sedation. Use Caution/Monitor.nalbuphinenalbuphine and amitriptyline both increase sedation. Use Caution/Monitor.naratriptannaratriptan and amitriptyline both increase serotonin levels. Modify Therapy/Monitor Closely.nefazodonenefazodone will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.nefazodone will increase the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.nefopamnefopam, amitriptyline. Mechanism: unspecified interaction mechanism. Use Caution/Monitor. Use combination with caution.nelfinavirnelfinavir will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.neostigmineneostigmine increases and amitriptyline decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.nicardipinenicardipine will increase the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.nifedipinenifedipine will decrease the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.norepinephrineamitriptyline 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.nortriptylineamitriptyline and nortriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.amitriptyline and nortriptyline both increase sedation. Use Caution/Monitor.ofloxacinamitriptyline and ofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.olanzapineolanzapine and amitriptyline both increase sedation. Use Caution/Monitor.olanzapine and amitriptyline both increase QTc interval. Use Caution/Monitor.oliceridineamitriptyline, 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.olodaterol inhaledamitriptyline 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 arrhythmiasonabotulinumtoxinAonabotulinumtoxinA and amitriptyline both decrease cholinergic effects/transmission. Modify Therapy/Monitor Closely.opium tinctureopium tincture and amitriptyline both increase sedation. Use Caution/Monitor.orphenadrineamitriptyline and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.orphenadrine and amitriptyline both increase sedation. Use Caution/Monitor.osilodrostatosilodrostat and amitriptyline both increase QTc interval. Use Caution/Monitor.osimertinibosimertinib 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.oxaliplatinoxaliplatin 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.oxazepamoxazepam and amitriptyline both increase sedation. Use Caution/Monitor.oxybutyninoxybutynin and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.oxybutynin topicaloxybutynin topical and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.oxybutynin transdermaloxybutynin transdermal and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.oxycodoneoxycodone and amitriptyline both increase sedation. Use Caution/Monitor.oxymetazoline intranasalamitriptyline 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.oxymorphoneoxymorphone and amitriptyline both increase sedation. Use Caution/Monitor.ozanimodozanimod 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.paliperidoneamitriptyline and paliperidone both increase QTc interval. Modify Therapy/Monitor Closely.paliperidone and amitriptyline both increase sedation. Use Caution/Monitor.pancuroniumpancuronium and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.papaveretumpapaveretum and amitriptyline both increase sedation. Use Caution/Monitor.papaverineamitriptyline and papaverine both increase sedation. Use Caution/Monitor.paroxetineamitriptyline and paroxetine both increase QTc interval. Modify Therapy/Monitor Closely.pasireotideamitriptyline and pasireotide both increase QTc interval. Modify Therapy/Monitor Closely.pazopanibamitriptyline and pazopanib both increase QTc interval. Use Caution/Monitor.peginterferon alfa 2bpeginterferon 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.pentazocinepentazocine and amitriptyline both increase sedation. Use Caution/Monitor.amitriptyline and pentazocine both increase serotonin levels. Modify Therapy/Monitor Closely.pentobarbitalpentobarbital 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.perphenazineperphenazine and amitriptyline both increase sedation. Use Caution/Monitor.phendimetrazineamitriptyline increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.phenobarbitalphenobarbital 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 affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.phenobarbital will decrease the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.phenobarbital and amitriptyline both increase sedation. Use Caution/Monitor.phentermineamitriptyline increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.phenylephrineamitriptyline increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.phenylephrine ophthalmicamitriptyline, 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 POamitriptyline increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .phenytoinphenytoin 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.pholcodineamitriptyline and pholcodine both increase sedation. Use Caution/Monitor.physostigminephysostigmine increases and amitriptyline decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.pilocarpinepilocarpine increases and amitriptyline decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.pimozidepimozide and amitriptyline both increase sedation. Use Caution/Monitor.pirbuterolamitriptyline increases and pirbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.ponatinibponatinib increases levels of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.posaconazoleamitriptyline and posaconazole both increase QTc interval. Modify Therapy/Monitor Closely.pralidoximepralidoxime and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.pregabalinpregabalin, amitriptyline. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.primidoneprimidone will decrease the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.primidone will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.primidone and amitriptyline both increase sedation. Use Caution/Monitor.prochlorperazineprochlorperazine and amitriptyline both increase QTc interval. Use Caution/Monitor.prochlorperazine and amitriptyline both increase sedation. Use Caution/Monitor.promethazinepromethazine and amitriptyline both increase QTc interval. Use Caution/Monitor.promethazine and amitriptyline both increase sedation. Use Caution/Monitor.propanthelinepropantheline and amitriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.propofolpropofol and amitriptyline both increase sedation. Use Caution/Monitor.propylhexedrineamitriptyline increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.protriptylineamitriptyline and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.amitriptyline and protriptyline both increase sedation. Use Caution/Monitor.pyridostigminepyridostigmine increases and amitriptyline decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.quazepamquazepam and amitriptyline both increase sedation. Use Caution/Monitor.quercetinquercetin will decrease the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.quetiapinequetiapine and amitriptyline both increase sedation. Use Caution/Monitor.quetiapine, amitriptyline. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.quinineamitriptyline and quinine both