nortriptyline hydrochloride

nortriptyline hydrochloride

(nor trip' ti leen)

Aventyl, Pamelor, PMS-Nortriptyline (CAN)

Pregnancy Category C

Drug class

TCA (secondary amine)

Therapeutic actions

Mechanism of action unknown; the TCAs are structurally related to the phenothiazine antipsychotic drugs (eg, chlorpromazine), but inhibit the presynaptic reuptake of the neurotransmitters norepinephrine and serotonin; anticholinergic at CNS and peripheral receptors; sedating; the relationship of these effects to clinical efficacy is unknown.

Indications

·        Relief of symptoms of depression (endogenous depression most responsive)

·        Unlabeled uses: Treatment of panic disorders (25–75 mg/day), premenstrual depression (50–125 mg/day), dermatologic disorders (75 mg/day), chronic pain, headache prophylaxis

Contraindications and cautions

·        Contraindicated with hypersensitivity to any tricyclic drug; concomitant therapy with an MAOI; recent MI; myelography within previous 24 hr or scheduled within 48 hr; pregnancy (limb reduction abnormalities); lactation.

·        Use cautiously with EST (increased hazard with TCAs); preexisting CV disorders (possibly increased risk of serious CVS toxicity); angle-closure glaucoma, increased IOP; urinary retention, ureteral or urethral spasm (anticholinergic effects may exacerbate these conditions); seizure disorders; hyperthyroidism (predisposes to CVS toxicity, including cardiac arrhythmias); impaired hepatic, renal function; psychiatric patients (schizophrenic or paranoid patients may exhibit a worsening of psychosis); manic-depressive disorder (may shift to hypomanic or manic phase); elective surgery (discontinued as long as possible before surgery).

Available forms

Capsules—10, 25, 50, 75 mg; solution—10 mg/5 mL

Dosages

ADULTS

25 mg tid–qid PO. Begin with low dosage and gradually increase as required and tolerated. Doses > 150 mg/day are not recommended.

PEDIATRIC PATIENTS > 12 YR

30–50 mg/day PO in divided doses.

PEDIATRIC PATIENTS < 12 YR

Not recommended.

GERIATRIC PATIENTS

30–50 mg/day PO in divided doses.

Pharmacokinetics

Route	Onset	Peak	Duration
Oral	Varies	2–4 hr	2–4 wk

Metabolism: Hepatic; T_1/2: 18–28 hr

Distribution: Crosses placenta; enters breast milk

Excretion: Urine

Adverse effects

·        CNS: Sedation and anticholinergic (atropine-like) effects (dry mouth, blurred vision, disturbance of accommodation for near vision, mydriasis, increased IOP), confusion (especially in elderly), disturbed concentration, hallucinations, disorientation, decreased memory, feelings of unreality, delusions, anxiety, nervousness, restlessness, agitation, panic, insomnia, nightmares, hypomania, mania, exacerbation of psychosis, drowsiness, weakness, fatigue, headache, numbness, tingling, paresthesias of extremities, incoordination, motor hyperactivity, akathisia, ataxia, tremors, peripheral neuropathy, extrapyramidalsymptoms, seizures, speech blockage, dysarthria

·        CV: Orthostatic hypotension, hypertension, syncope, tachycardia, palpitations, MI, arrhythmias, heart block, precipitation of CHF, stroke

·        Endocrine: Elevated or depressed blood sugar; elevated prolactin levels; inappropriate ADH secretion

·        GI: Dry mouth, constipation, paralytic ileus, nausea, vomiting, anorexia, epigastric distress, diarrhea, flatulence, dysphagia, peculiar taste, increased salivation, stomatitis, glossitis, parotid swelling, abdominal cramps, black tongue, hepatitis; elevated transaminase, altered alkaline phosphatase

·        GU: Urinary retention, delayed micturition, dilation of the urinary tract, gynecomastia, testicular swelling; breast enlargement, menstrual irregularity andgalactorrhea; increased or decreased libido; impotence

·        Hematologic: Bone marrow depression, including agranulocytosis; eosinophilia; purpura; thrombocytopenia; leukopenia

·        Hypersensitivity: Rash, pruritus, vasculitis, petechiae, photosensitization, edema (generalized, facial, tongue), drug fever

·        Withdrawal: Symptoms with abrupt discontinuation of prolonged therapy: nausea, headache, vertigo, nightmares, malaise

·        Other: Nasal congestion, excessive appetite, weight gain or loss; sweating, alopecia, lacrimation, hyperthermia, flushing, chills

Interactions

Drug-drug

·        Increased TCA levels and pharmacologic (especially anticholinergic) effects with cimetidine, fluoxetine

·        Altered response, including arrhythmias and hypertension with sympathomimetics

·        Risk of severe hypertension with clonidine

·        Hyperpyretic crises, severe seizures, hypertensive episodes, and deaths when MAOIs are given with TCAs

·        Decreased hypotensive activity of guanethidine

Note: MAOIs and TCAs have been used successfully in some patients resistant to therapy with single agents; however, case reports indicate that the combination can cause serious and potentially fatal adverse effects.

Nursing considerations

Assessment

·        History: Hypersensitivity to any tricyclic drug; concomitant therapy with an MAOI; recent MI; myelography within previous 24 hr or scheduled within 48 hr; pregnancy; lactation; EST; preexisting CV disorders; angle-closure glaucoma, increased IOP, urinary retention, ureteral or urethral spasm; seizure disorders; hyperthyroidism; impaired hepatic, renal function; psychiatric patients; manic-depressive patients; elective surgery

·        Physical: Weight; T; skin color, lesions; orientation, affect, reflexes, vision and hearing; P, BP, orthostatic BP, perfusion; bowel sounds, normal output, liver evaluation; urine flow, normal output; usual sexual function, frequency of menses, breast and scrotal examination; LFTs, urinalysis, CBC, ECG

Interventions

·        WARNING: Limit drug access to depressed and potentially suicidal patients.

·        When doses of > 100 mg/day are given, plasma levels of nortriptyline should be monitored and maintained in the range of 50 to 150 ng/mL.

·        Give major portion of dose hs if drowsiness, severe anticholinergic effects occur.

·        Reduce dosage if minor side effects develop; discontinue if serious side effects occur.

·        Arrange for CBC if patient develops fever, sore throat, or other sign of infection.

Teaching points

·        Take drug exactly as prescribed; do not stop taking this drug abruptly or without consulting your health care provider.

·        Avoid alcohol, other sleep-inducing, over-the-counter drugs.

·        Avoid prolonged exposure to sunlight or sunlamps; use a sunscreen or protective garments if possible.

·        You may experience these side effects: Headache, dizziness, drowsiness, weakness, blurred vision (reversible; use safety measures if severe; avoid driving or performing tasks that require alertness); nausea, vomiting, loss of appetite, dry mouth (eat frequent small meals, perform frequent mouth care, and suck sugarless candy); nightmares, inability to concentrate, confusion; changes in sexual function.

·        Report dry mouth, difficulty in urination, excessive sedation.

Adverse effects in Italic are most common; those in Bold are life-threatening.