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Monday, February 14, 2022

Amitriptyline: Uses, Indications, Dosages, Precautions, Contraindications, Side Effects & Interactions

Amitriptyline: Uses, Indications, Dosages, Precautions, Contraindications, Side Effects & Interactions

Amitriptyline

(a-mi-trip-ti-leen)
Classification 
Pharmacotherapeutic: Tricyclic
Clinical: Antidepressant, antineuralgic, antibulimic
Apo-Amitriptyline
Levate
Novo-Tryptyn
Elavil
CATEGORY AND SCHEDULE
Pregnancy Risk Category: C
Do not confuse:
amitriptyline/nortriptyline/aminophylline

General Information

Amitriptyline belongs to the tricyclic group of antidepressant drugs. They are effective for long-term depression, but are poorly tolerated and dangerous in the case of an overdose, making them second-line options after SSRI antidepressants. The sedative effect of amitriptyline is helpful when depression is accompanied by anxiety or insomnia. Taken at night, the drug promotes sleep and reduces the need for additional sleeping drugs. Amitriptyline is sometimes used to treat nocturnal enuresis (bedwetting) in children. It can also be used to treat neuropathic pain, such as postherpetic neuralgia after shingles, and to prevent migraines. In overdose, amitriptyline can cause abnormal heart rhythms, seizures and coma

Azithromycin can cause severe reactions, such as: Overdose can cause confusion, seizures, severe somnolence, arrhythmias, fever, hallucinations, agitation, dyspnea, vomiting and unusual tiredness or weakness. Abrupt discontinuation after prolonged therapy can cause headache, malaise, nausea, vomiting, and intense dreams, and blood dyscrasias and cholestatic jaundice rarely occur

Action

A tricyclic antidepressant that blocks the reuptake of neurotransmitters, including norepinephrine and serotonin, at presynaptic membranes, increasing their availability at postsynaptic receptor sites. It also has strong anticholinergic activity

Therapeutic Effect

Antidepressant effect

Availability (Rx)

Tablets: 10 mg, 25 mg, 50 mg, 75 mg, 100 mg, 150 mg

Uses

Major depression
Unlabeled uses: Neuropathic pain, related to diabetic neuropathy or postherpetic neuralgia; treatment of migraine. Treatment of depression in children, post traumatic stress disorder (PTSD), treatment of bulimia nervosa, hiccups, social phobia

Precautions

Pregnancy (C), breastfeeding, geriatric patients, seizure disorders, prostatic hypertrophy, schizophrenia, psychosis, severe depression, increased intraocular pressure, closed-angle glaucoma, urinary retention, renal/hepatic/cardiac disease, hyperthyroidism, electroshock therapy, elective surgery
Black Box Warning: Children ,12 yr, suicidal patients
Make sure to tell your doctor if:
• You have heart problems
• You have had epileptic seizures
• You have long-term liver or kidney problems
• You have glaucoma
• You have prostate trouble
• You have thyroid disease
• You have had mania or a psychotic illness
• You are taking other medicines

Indications and Dosages

‣ To Treat Depression

PO
 Adults: 25-75 mg/day as single dose at bedtime or in divided doses, may increase to 200 mg/day; max 300 mg/day (if hospitalized)
 Geriatric: 10-25 mg at bedtime, may be increased to 150 mg/day

‣ To Treat Cluster/migraine headache (unlabeled)

PO
• Adults: 10-300 mg/day

‣ To Treat Herpes labialis (cold sores), recurrent

TOPICAL (CREAM)
• Adults, Children 12 yr and older. Apply 5 times per day for 4 days (during the prodrome or when lesions appear)

‣ To Treat Pain (unlabeled)

PO
• Adults: 75-300 mg/day

‣ To Treat Fibromyalgia/insomnia (unlabeled)

PO
• Adult: 10-50 mg nightly

‣ To Treat Enuresis (unlabeled)

PO
• Child 11-14 yr: PO 50 mg at bedtime
• Child 6-10 yr: PO 25 mg at bedtime

‣ To Treat ADHD/bulimia nervosa (unlabeled)

PO
• Adult: PO 25 mg tid, titrate to 200 mg/day by 25-50 mg at weekly intervals
• Child 6-12 yr: PO 10-30 mg/day or 1-5 mg/kg/day in divided doses

Pharmacokinetics

Rapidly and well absorbed from the GI tract. Protein binding: 90%. Undergoes first-pass metabolism in the liver. Nortriptyline is an active metabolite. Metabolites excreted in urine. Minimal removal by hemodialysis. Half-life: 10-26 h

Implementation

PO route

• Give with food or milk for GI symptoms
• Crush if patient is unable to swallow medication whole
• Give dose at bedtime if oversedation occurs during day; may take entire dose at bedtime; geriatric may not tolerate once/day dosing
• Store at room temperature; do not freeze

Contraindications

Acute recovery period after MI; use within 14 days of MAOIs, hypersensitivity
Cautions: Prostatic hypertrophy, history of urinary retention or obstruction, narrow-angle glaucoma, diabetes, seizures, hyperthyroidism, cardiac/hepatic/renal disease, schizophrenia, xerostomia, visual problems, constipation or bowel obstruction, elderly, increased intraocular pressure (IOP), hiatal hernia, suicidal ideation

Interactions

Individual drugs

• Alcohol: increased CNS depression
• Amiodarone, procainamide, quiNIDine: increased QT prolongation
• CarBAMazepine: increased amitriptyline levels, increased toxicity
• Cimetidine, fluoxetine: increased levels, increased toxicity
• CloNIDine: decreased effects
• Guanethidine: decreased effects
• Linezolid, methylene blue: increased serotonin syndrome, use cautiously

Drug classifications

• Antidepressants, antidysrhythmics (class IC), phenothiazines: increased amitriptyline levels, toxicity
 Antidysrhythmics (class IA, III), tricyclic antidepressants: increased QT prolongation
 Antithyroid agents: increased risk of agranulocytosis 
 Barbiturates, benzodiazepines, CNS depressants, opioids, sedative/hypnotics, sympathomimetics (direct acting): increased CNS effects
 MAOIs: hypertensive crisis, seizures, hyperpyretic crisis, do not use 14 days of MAOIs
 Oral contraceptives: increased effects, toxicity
 Sympathomimetics (indirect acting): decreased effects

Drug/laboratory tests

• May alter EKG readings (flattened T wave), serum glucose
(increase or decrease). 
• Therapeutic serum level: Peak: 120–250 ng/mL; toxic serum level: greater than 500 ng/mL

Drugs/food

• None known

Herbal

• None significant

Side effects

CNS:  Anxiety, ataxia, coma, chills, delusions, disorientation, drowsiness, extrapyramidal reactions, fatigue, fever, headache, insomnia, nightmares, peripheral neuropathy, suicidal ideation, tremor
 CV: Arrhythmias (including prolonged AV conduction, heart block, and tachycardia), cardiomyopathy, hypertension, MI, nonspecific ECG changes, orthostatic hypotension, palpitations
 EENT: Abnormal taste, black tongue, blurred vision, dry mouth, increased salivation, nasal congestion, tinnitus
 ENDO: Gynecomastia, increased or decreased blood glucose level, increased prolactin level, syndrome of inappropriate ADH secretion
 GI: Abdominal cramps, constipation, diarrhea, flatulence, ileus, increased appetite, nausea, vomiting
 GU: Impotence, libido changes, menstrual irregularities, testicular swelling, urinary hesitancy, urine retention
 HEME: Agranulocytosis, bone marrow depression, eosinophilia, leukopenia,
thrombocytopenia
 SKIN: Alopecia, flushing, purpura Other:Weight gain
 

Nursing considerations

Baseline assessment

• Observe and record behavior. 
 Assess psychological status, thought content, suicidal ideation, sleep patterns, appearance, interest in environment. For pts on long-term therapy, hepatic/renal function tests, blood counts should be performed periodically

Intervention/evaluation

• Supervise suicidal-risk pt closely during early therapy (as depression lessens,
energy level improves, increasing suicide potential)
 Assess appearance, behavior, speech pattern, level of interest, mood. Monitor B/P for hypotension, pulse, arrhythmias. Therapeutic serum level: Peak: 120–250 ng/mL; toxic serum level: greater than 500 ng/mL

Equipment must be available for anaphylaxis

• Monitor B/P (with patient lying, standing), pulse q4hr; if systolic B/P drops 20 mm Hg, hold product, notify prescriber; take VS q4hr in patients with cardiovascular disease
• Monitor blood studies: CBC, leukocytes, differential, cardiac enzymes if patient is receiving long-term therapy, thyroid function tests 
• Monitor hepatic studies: AST, ALT, bilirubin
• Check weight weekly; appetite may increase with product
• Assess ECG for flattening of T wave, bundle branch block, AV block, prolongation of QTc interval, dysrhythmias in cardiac patients, avoid use immediately after MI
• Assess for EPS primarily in geriatric: rigidity, dystonia, akathisia
• Assess mental status: mood, sensorium, affect, suicidal tendencies; increase in psychiatric symptoms: depression, panic
• Monitor urinary retention, constipation; constipation is more likely to occur in children or geriatric
• Assess for paralytic ileus, glaucoma exacerbation
• Assess for withdrawal symptoms: headache, nausea, vomiting, muscle pain, weakness; do not usually occur unless product was discontinued abruptly
• Identify alcohol consumption; if alcohol is consumed, hold dose until morning
• Assess for sexual dysfunction: erectile dysfunction, decreased libido; usually resolves after discontinuing product

Evaluation

Positive therapeutic result
• Decreased depression
• Absence of suicidal thoughts

Patient/family teaching

• Instruct patient to take amitriptyline at bedtime to avoid daytime drowsiness.
• Instruct patient to avoid using alcohol or OTC drugs that contain alcohol during
amitriptyline therapy because alcohol enhances CNS depressant effects
• Tell patient to sips of water may relieve dry mouth
• Tell patient to go slowly from lying to standing
• Tell patient to report visual disturbances
• Tell patient do not abruptly discontinue medication
• Inform patient to avoid tasks that require alertness, motor skills until response to drug is established
• Inform patient to tolerance to postural hypotension, sedative and anticholinergic effects usually develops during early therapy
• Inform patient that maximum therapeutic effect may be noted in 2–4 wks
• Tell patient do Sensitivity to sun may occur
• Tell patient do urge family or caregiver to watch the patient closely for suicidal tendencies, especially when therapy starts or dosage changes and particularly if patient is a child, teenager, or young adult

Treatment of Overdose:

ECG monitoring, lavage, administer anticonvulsant, sodium bicarbonate

1 comment:

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