Caution/Monitor.glycopyrrolateglycopyrrolate and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.protriptyline increases levels of glycopyrrolate by unknown mechanism. Use Caution/Monitor.glycopyrrolate inhaledglycopyrrolate inhaled and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.protriptyline increases levels of glycopyrrolate inhaled by unknown mechanism. Use Caution/Monitor.glycopyrronium tosylate topicalglycopyrronium tosylate topical, protriptyline. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration of glycopyrronium tosylate topical with other anticholinergic medications may result in additive anticholinergic adverse effects.granisetrongranisetron and protriptyline both increase QTc interval. Use Caution/Monitor.haloperidolhaloperidol and protriptyline both increase sedation. Use Caution/Monitor.henbanehenbane and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.homatropinehomatropine and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.huperzine Ahuperzine A increases and protriptyline decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.hydrocodonehydrocodone, protriptyline. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration of drugs that affect the serotonergic neurotransmitter system may result in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment.hydromorphonehydromorphone and protriptyline both increase sedation. Use Caution/Monitor.hydroxyzinehydroxyzine and protriptyline both increase sedation. Use Caution/Monitor.hydroxyzine and protriptyline both increase QTc interval. Use Caution/Monitor.hyoscyaminehyoscyamine and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.hyoscyamine sprayhyoscyamine spray and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.iloperidoneprotriptyline and iloperidone both increase QTc interval. Modify Therapy/Monitor Closely.iloperidone and protriptyline both increase sedation. Use Caution/Monitor.imipramineimipramine and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.imipramine and protriptyline both increase sedation. Use Caution/Monitor.indacaterol, inhaledindacaterol, inhaled, protriptyline. QTc interval. Use Caution/Monitor. Indacaterol should be administered with extreme caution to patients treated with TCAs. Drugs that are known to prolong the QTc interval may have an increased the risk of ventricular arrhythmias.ipratropiumipratropium and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.isofluraneisoflurane and protriptyline both increase QTc interval. Use Caution/Monitor.isoniazidprotriptyline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.isoproterenolprotriptyline increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.ketamineketamine and protriptyline both increase sedation. Use Caution/Monitor.ketotifen, ophthalmicprotriptyline and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.L-tryptophanprotriptyline and L-tryptophan both increase serotonin levels. Modify Therapy/Monitor Closely.lapatinibprotriptyline and lapatinib both increase QTc interval. Modify Therapy/Monitor Closely.lasmiditanlasmiditan, protriptyline. 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.protriptyline increases effects of lasmiditan by serotonin levels. Use Caution/Monitor. Coadministration may increase risk of serotonin syndrome.lemborexantlemborexant, protriptyline. 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.levalbuterolprotriptyline increases and levalbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.levofloxacinprotriptyline and levofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.levorphanollevorphanol and protriptyline both increase sedation. Use Caution/Monitor.levothyroxinelevothyroxine increases effects of protriptyline by Other (see comment). Use Caution/Monitor. Comment: Increased catecholamine receptor sensitivity; may increase CNS and cardiovascular effects, including arrhythmias.liothyronineliothyronine increases effects of protriptyline by Other (see comment). Use Caution/Monitor. Comment: Increased catecholamine receptor sensitivity; may increase CNS and cardiovascular effects, including arrhythmias.liotrixliotrix increases effects of protriptyline by Other (see comment). Use Caution/Monitor. Comment: Increased catecholamine receptor sensitivity; may increase CNS and cardiovascular effects, including arrhythmias.lisdexamfetamineprotriptyline increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.protriptyline, 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).lithiumprotriptyline and lithium both increase serotonin levels. Modify Therapy/Monitor Closely.lithium and protriptyline both increase QTc interval. Use Caution/Monitor.lofepraminelofepramine and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.lofepramine and protriptyline both increase sedation. Use Caution/Monitor.lofexidineprotriptyline and lofexidine both increase sedation. Use Caution/Monitor.protriptyline decreases effects of lofexidine by unspecified interaction mechanism. Use Caution/Monitor.loprazolamloprazolam and protriptyline both increase sedation. Use Caution/Monitor.lorazepamlorazepam and protriptyline both increase sedation. Use Caution/Monitor.lorcaserinlorcaserin will increase the level or effect of protriptyline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.lormetazepamlormetazepam and protriptyline both increase sedation. Use Caution/Monitor.loxapineloxapine and protriptyline both increase sedation. Use Caution/Monitor.loxapine inhaledloxapine inhaled and protriptyline both increase sedation. Use Caution/Monitor.lsdprotriptyline and lsd both increase serotonin levels. Modify Therapy/Monitor Closely.lurasidonelurasidone, protriptyline. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for additive CNS effects .maprotilinemaprotiline and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.maprotiline and protriptyline both increase sedation. Use Caution/Monitor.marijuanaprotriptyline and marijuana both increase sedation. Use Caution/Monitor.meclizinemeclizine and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.melatoninprotriptyline and melatonin both increase sedation. Use Caution/Monitor.meperidinemeperidine and protriptyline both increase sedation. Use Caution/Monitor.meprobamateprotriptyline and meprobamate both increase sedation. Use Caution/Monitor.metaproterenolprotriptyline increases and metaproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.metaxalonemetaxalone and protriptyline both increase sedation. Use Caution/Monitor.methadoneprotriptyline and methadone both increase QTc interval. Modify Therapy/Monitor Closely.methadone and protriptyline both increase sedation. Use Caution/Monitor.methamphetamineprotriptyline increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.methocarbamolmethocarbamol and protriptyline both increase sedation. Use Caution/Monitor.methscopolaminemethscopolamine and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.methylenedioxymethamphetamineprotriptyline increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.methylphenidateprotriptyline, 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 protriptyline 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 protriptyline both increase sedation. Use Caution/Monitor.midodrineprotriptyline increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.mifepristonemifepristone, protriptyline. QTc interval. Modify Therapy/Monitor Closely. Use alternatives if available.mirabegronmirabegron will increase the level or effect of protriptyline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.mirtazapineprotriptyline and mirtazapine both increase sedation. Use Caution/Monitor.protriptyline and mirtazapine both increase serotonin levels. Modify Therapy/Monitor Closely.modafinilprotriptyline increases and modafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.morphinemorphine and protriptyline both increase sedation. Use Caution/Monitor.protriptyline and morphine both increase serotonin levels. Modify Therapy/Monitor Closely.motherwortprotriptyline and motherwort both increase sedation. Use Caution/Monitor.moxonidineprotriptyline and moxonidine both increase sedation. Use Caution/Monitor.nabiloneprotriptyline and nabilone both increase sedation. Use Caution/Monitor.nalbuphinenalbuphine and protriptyline both increase sedation. Use Caution/Monitor.naratriptannaratriptan and protriptyline both increase serotonin levels. Modify Therapy/Monitor Closely.nefopamnefopam, protriptyline. Mechanism: unspecified interaction mechanism. Use Caution/Monitor. Use combination with caution.neostigmineneostigmine increases and protriptyline decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.norepinephrineprotriptyline increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.protriptyline increases effects of norepinephrine by unknown mechanism. Use Caution/Monitor.nortriptylinenortriptyline and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.nortriptyline and protriptyline both increase sedation. Use Caution/Monitor.ofloxacinprotriptyline and ofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.olanzapineolanzapine and protriptyline both increase sedation. Use Caution/Monitor.olanzapine and protriptyline both increase QTc interval. Use Caution/Monitor.oliceridineprotriptyline, oliceridine. Either increases effects of the other by serotonin levels. Modify Therapy/Monitor Closely.protriptyline 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 inhaledprotriptyline 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 protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.opium tinctureopium tincture and protriptyline both increase sedation. Use Caution/Monitor.orphenadrineprotriptyline and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.orphenadrine and protriptyline both increase sedation. Use Caution/Monitor.osimertinibosimertinib and protriptyline both increase QTc interval. Use Caution/Monitor. Conduct periodic monitoring with ECGs and electrolytes in patients taking drugs known to prolong the QTc interval.oxazepamoxazepam and protriptyline both increase sedation. Use Caution/Monitor.oxybutyninoxybutynin and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.oxybutynin topicaloxybutynin topical and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.oxybutynin transdermaloxybutynin transdermal and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.oxycodoneoxycodone and protriptyline both increase sedation. Use Caution/Monitor.oxymetazoline intranasalprotriptyline 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 protriptyline both increase sedation. Use Caution/Monitor.ozanimodozanimod and protriptyline 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.paliperidoneprotriptyline and paliperidone both increase QTc interval. Modify Therapy/Monitor Closely.paliperidone and protriptyline both increase sedation. Use Caution/Monitor.pancuroniumpancuronium and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.papaveretumpapaveretum and protriptyline both increase sedation. Use Caution/Monitor.papaverineprotriptyline and papaverine both increase sedation. Use Caution/Monitor.paroxetineprotriptyline and paroxetine both increase QTc interval. Modify Therapy/Monitor Closely.pasireotideprotriptyline and pasireotide both increase QTc interval. Modify Therapy/Monitor Closely.pazopanibprotriptyline and pazopanib both increase QTc interval. Use Caution/Monitor.peginterferon alfa 2bpeginterferon alfa 2b, protriptyline. 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 protriptyline both increase sedation. Use Caution/Monitor.protriptyline and pentazocine both increase serotonin levels. Modify Therapy/Monitor Closely.pentobarbitalpentobarbital and protriptyline both increase sedation. Use Caution/Monitor.perphenazineperphenazine and protriptyline both increase sedation. Use Caution/Monitor.phendimetrazineprotriptyline increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.phenobarbitalphenobarbital and protriptyline both increase sedation. Use Caution/Monitor.phentermineprotriptyline increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.phenylephrineprotriptyline increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.phenylephrine ophthalmicprotriptyline, 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 POprotriptyline increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .pholcodineprotriptyline and pholcodine both increase sedation. Use Caution/Monitor.physostigminephysostigmine increases and protriptyline decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.pilocarpinepilocarpine increases and protriptyline decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.pimozidepimozide and protriptyline both increase sedation. Use Caution/Monitor.pirbuterolprotriptyline increases and pirbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.posaconazoleprotriptyline and posaconazole both increase QTc interval. Modify Therapy/Monitor Closely.pralidoximepralidoxime and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.pregabalinpregabalin, protriptyline. 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 and protriptyline both increase sedation. Use Caution/Monitor.prochlorperazineprochlorperazine and protriptyline both increase QTc interval. Use Caution/Monitor.prochlorperazine and protriptyline both increase sedation. Use Caution/Monitor.promethazinepromethazine and protriptyline both increase QTc interval. Use Caution/Monitor.promethazine and protriptyline both increase sedation. Use Caution/Monitor.propanthelinepropantheline and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.propofolpropofol and protriptyline both increase sedation. Use Caution/Monitor.propylhexedrineprotriptyline increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.pyridostigminepyridostigmine increases and protriptyline decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.quazepamquazepam and protriptyline both increase sedation. Use Caution/Monitor.quetiapinequetiapine and protriptyline both increase sedation. Use Caution/Monitor.quetiapine, protriptyline. 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.quinineprotriptyline and quinine both increase QTc interval. Use Caution/Monitor.ramelteonprotriptyline and ramelteon both increase sedation. Use Caution/Monitor.ranolazineprotriptyline and ranolazine both increase QTc interval. Modify Therapy/Monitor Closely.rapacuroniumrapacuronium and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.remimazolamremimazolam, protriptyline. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.rifabutinrifabutin decreases levels of protriptyline by increasing metabolism. Use Caution/Monitor.rilpivirinerilpivirine increases toxicity of protriptyline by QTc interval. Use Caution/Monitor. Rilpivirine should be used with caution when co-administered with a drug with a known risk of Torsade de Pointes.risperidoneprotriptyline and risperidone both increase QTc interval. Modify Therapy/Monitor