NORTRIPTYLINE HYDROCHLORIDE

NORTRIPTYLINE HYDROCHLORIDE
(nor-trip'ti-leen)
Aventyl, Pamelor
Classifications: psychotherapeutic; tricyclic antidepressant;
Therapeutic: tricyclic antidepressant
Prototype: Imipramine
Pregnancy Category: D

Availability

10 mg, 25 mg, 50 mg, 75 mg capsules; 10 mg/5 mL solution

Action

Secondary amine derivative of amitriptyline that enhances action of norepinephrine and serotonin by blocking their reuptake at the neuronal membrane. Nortriptyline is more likely to inhibit the reuptake of serotonin than norepinephrine.

Therapeutic Effect

Mood elevation may be due to its inhibition of reuptake of serotonin at the presynaptic membrane.

Uses

Endogenous depression. Similar in actions, uses, limitations, and interactions to imipramine.

Unlabeled Uses

Nocturnal enuresis in children.

Contraindications

Hypersensititivity to tricyclic antidepressants; acute recovery period after MI; AV block; history of QT prolongation; suicidal ideation; during or within 14 d of MAO inhibitor therapy. Children <12 y, pregnancy (category D), lactation.

Cautious Use

Narrow-angle glaucoma, cardiac disease; hyperthyroidism, concurrent administration of thyroid medications, concurrent use with electroshock therapy; history of suicides; Parkinson's disease; asthma; bipolar disorder.

Route & Dosage

Antidepressant
Adult: PO 25 mg t.i.d. or q.i.d., gradually increased to 100–150 mg/d
Geriatric: PO Start with 10–25 mg h.s., increase by 25 mg q3d to 75 mg h.s. (max: 150 mg/d)
Adolescent: PO 30–50 mg/d in divided doses
Child (6–12 y): PO 10–20 mg/d in 3–4 divided doses

Nocturnal Enuresis
Child: PO 6–7 y, 10 mg/d; 8–11 y, 10–20 mg/d; >11 y, 25–35 mg/d given 30 min before h.s.

Administration

Oral

Give with food to decrease gastric distress.
In older adults, total daily dose may be given once a day h.s. (preferred).
Be aware that Aventyl is a 4% alcohol solution.
Supervise drug ingestion to be sure patient swallows medication.
Store at 15°–30° C (59°–86° F) in tightly closed container.

Adverse Effects (≥1%)

Body as a Whole: Tremors, hyperhydrosis. CV: Orthostatic hypotension. GI: Paralytic ileus, dry mouth. Hematologic: Agranulocytosis (rare). CNS: Drowsiness, confusional state (especially in older adults and with high dosage). Skin: Photosensitivity reaction. Special Senses: Blurred vision. Urogenital: Urinary retention.

Interactions

Drug: May decrease response to antihypertensives; cns depressants, alcohol, hypnotics, barbiturates, sedatives potentiate CNS depression; may increase hypoprothrombinemic effect of oral anticoagulants; levodopa, sympathomimetics (e.g., epinephrine, norepinephrine) pose possibility of sympathetic hyperactivity with hypertension and hyperpyrexia; mao inhibitors pose possibility of severe reactions: toxic psychosis, cardiovascular instability; methylphenidate increases plasma TCA levels; thyroid drugs may increase possibility of arrhythmias; cimetidine may increase plasma TCA levels. Herbal: Ginkgo may decrease seizure threshold. St. John's wort may cause serotonin syndrome (see Appendix F).

Pharmacokinetics

Absorption: Rapidly from GI tract. Peak: 7–8.5 h. Duration: Crosses placenta; distributed in breast milk. Metabolism: In liver (CYP2D6). Elimination: Primarily in urine. Half-Life: 16–90 h.

Nursing Implications

Assessment & Drug Effects

Be aware that nortriptyline has a narrow therapeutic plasma level range, or "therapeutic window." Drug levels above or below the therapeutic window are associated with decreased rate of response.
Therapeutic response may not occur for 2 wk or more.
Monitor carefully for signs and symptoms of suicidality in children and adults.
Monitor BP and pulse rate during adjustment period of TCA therapy. If systolic BP falls more than 20 mm Hg or if there is a sudden increase in pulse rate, withhold medication and notify the physician.
Notify physician if psychotic signs increase. Because of the small therapeutic window, a substitute TCA may be prescribed rather than an increase in dosage.
Inspect oral membranes daily if patient is on high doses of TCA. Urge outpatient to report stomatitis or dry mouth. Sore mouth can be a major cause of poor nutrition and noncompliance. Consult physician about use of a saliva substitute (e.g., VA-Oralube, Moi-Stir).
Monitor bowel elimination pattern and I&O ratio. Urinary retention and severe constipation are potential problems, especially in older adults. Advise increased fluid intake; consult physician about stool softener.
Observe patient with history of glaucoma. Symptoms that may signal acute attack (severe headache, eye pain, dilated pupils, halos of light, nausea, vomiting) should be reported promptly.
Report reduction or alleviation of fine tremors.
Be aware that alcohol potentiation may increase the danger of overdosage or suicide attempt.

Patient & Family Education

Be aware that your ability to perform tasks requiring alertness and skill may be impaired.
Do not use OTC drugs unless physician approves.
Consult physician about safe amount of alcohol, if any, that can be ingested. Alcohol and nortriptyline both have increased effects when used together and for up to 2 wk after the TCA is discontinued.
Nortriptyline enhances the effects of barbiturates and other CNS depressants are enhanced.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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