Amitryn

Amitryn hydrochloride is a dibenzocycloheptene-derivative tricyclic antidepressant (TCA). TCAs are structurally similar to phenothiazines. They contain a tricyclic ring system with an alkyl amine substituent on the central ring. In non-depressed individuals, Amitryn does not affect mood or arousal, but may cause sedation. In depressed individuals, Amitryn exerts a positive effect on mood. TCAs are potent inhibitors of serotonin and norepinephrine reuptake. Tertiary amine TCAs, such as Amitryn, are more potent inhibitors of serotonin reuptake than secondary amine TCAs, such as nortriptyline. TCAs also down-regulate cerebral cortical β-adrenergic receptors and sensitize post-synaptic serotonergic receptors with chronic use. The antidepressant effects of TCAs are thought to be due to an overall increase in serotonergic neurotransmission. TCAs also block histamine-H1 receptors, α1-adrenergic receptors and muscarinic receptors, which accounts for their sedative, hypotensive and anticholinergic effects (e.g. blurred vision, dry mouth, constipation, urinary retention), respectively. See toxicity section below for a complete listing of side effects. Amitryn may be used to treat depression, chronic pain (unlabeled use), irritable bowel syndrome (unlabeled use), diabetic neuropathy (unlabeled use), post-traumatic stress disorder (unlabeled use), and for migraine prophylaxis (unlabeled use).

Depression (especially with anxiety, agitation and sleep disorders, including childhood, endogenous, involutional, reactive, neurotic, drug, and organic brain damage, alcohol withdrawal), schizophrenic psychoses, mixed emotional disorders, behavioral disorders (activity and attention), nocturnal enuresis (except in patients with hypotonia of the bladder), bulimia nervosa, chronic pain syndrome (chronic pain in cancer patients, migraine, rheumatic pain, atypical facial pain, postherpetic neuralgia, posttraumatic neuropathy, diabetic neuropathy, peripheral neuropathy), prophylaxis of migraine, peptic ulcer and duodenal ulcer.

Amitryn is a tricyclic antidepressant. Amitryn affects chemicals in the brain that may be unbalanced in people with depression.

Amitryn is used to treat symptoms of depression.

Amitryn may also be used for purposes not listed in this medication guide.

Dosage should be initiated at a low level and increased gradually, noting carefully the clinical response and any evidence of intolerance.

Initial Dosage For Adults

For outpatients 75 mg of Amitryn HCl a day in divided doses is usually satisfactory. If necessary, this may be increased to a total of 150 mg per day. Increases are made preferably in the late afternoon and/or bedtime doses. A sedative effect may be apparent before the antidepressant effect is noted, but an adequate therapeutic effect may take as long as 30 days to develop.

An alternate method of initiating therapy in outpatients is to begin with 50 to 100 mg Amitryn HCl at bedtime. This may be increased by 25 or 50 mg as necessary in the bedtime dose to a total of 150 mg per day.

Hospitalized patients may require 100 mg a day initially. This can be increased gradually to 200 mg a day if necessary. A small number of hospitalized patients may need as much as 300 mg a day.

Adolescent And Elderly Patients

In general, lower dosages are recommended for these patients. Ten mg 3 times a day with 20 mg at bedtime may be satisfactory in adolescent and elderly patients who do not tolerate higher dosages.

Maintenance

The usual maintenance dosage of Amitryn HCl is 50 to 100 mg per day. In some patients 40 mg per day is sufficient. For maintenance therapy the total daily dosage may be given in a single dose preferably at bedtime. When satisfactory improvement has been reached, dosage should be reduced to the lowest amount that will maintain relief of symptoms. It is appropriate to continue maintenance therapy 3 months or longer to lessen the possibility of relapse.

Usage In Pediatric Patients

In view of the lack of experience with the use of this drug in pediatric patients, it is not recommended at the present time for patients under 12 years of age.

Plasma Levels

Because of the wide variation in the absorption and distribution of tricyclic antidepressants in body fluids, it is difficult to directly correlate plasma levels and therapeutic effect. However, determination of plasma levels may be useful in identifying patients who appear to have toxic effects and may have excessively high levels, or those in whom lack of absorption or noncompliance is suspected. Because of increased intestinal transit time and decreased hepatic metabolism in elderly patients, plasma levels are generally higher for a given oral dose of Amitryn hydrochloride than in younger patients.

Elderly patients should be monitored carefully and quantitative serum levels obtained as clinically appropriate. Adjustment in dosage should be made according to the patient's clinical response and not on the basis of plasma levels.**

How supplied

10 mg tablets are blue, round, unscored, film coated tablets, debossed “2101” on one side and debossed “V” on the reverse side. They are supplied as follows:

Bottles of 30: NDC 0603-2212-16

Bottles of 90: NDC 0603-2212-02

Bottles of 100: NDC 0603-2212-21

Bottles of 1000: NDC 0603-2212-32

25 mg tablets are yellow, round, unscored, film coated tablets, debossed “2102” on one side and debossed “V” on the reverse side. They are supplied as follows:

Bottles of 90: NDC 0603-2213-02

Bottles of 100: NDC 0603-2213-21

Bottles of 1000: NDC 0603-2213-32

Bottles of 2500: NDC 0603-2213-30

50 mg tablets are beige, round, unscored, film coated tablets, debossed “2103” on one side and debossed “V” on the reverse side. They are supplied as follows:

Bottles of 100: NDC 0603-2214-21

Bottles of 1000: NDC 0603-2214-32

75 mg tablets are orange, round, unscored, film coated tablets, debossed “2104” and “V”. They are supplied as follows:

Bottles of 100: NDC 0603-2215-21

Bottles of 300: NDC 0603-2215-25

100 mg tablets are mauve, round, unscored, film coated tablets, debossed “2105” and “V”. They are supplied as follows:

Bottles of 100: NDC 0603-2216-21

Bottles of 300: NDC 0603-2216-25

150 mg tablets are blue, capsule shaped, unscored, film coated tablets, debossed “2106” on one side and debossed “V” on the reverse side. They are supplied as follows:

Bottles of 100: NDC 0603-2217-21

Bottles of 300: NDC 0603-2217-25

Storage And Handling

Storage

Store in a well-closed container. Store at 20°-25°C (68°-77°F). In addition, Amitryn tablets must be protected from light and stored in a well-closed, light-resistant container

REFERENCES

Ayd FJ Jr: Amitryn therapy for depressive reactions. Psychosomatics 1960;1:320–325.

Diamond S: Human metabolizer of Amitryn tagged with carbon 14. Curr Ther Res, Mar 1965, pp 170–175.

Dorfman W: Clinical experiences with Amitryn: A preliminary report. Psychosomatics 1960;1:153– 155.

Fallette JM, Stasney CR, Mintz AA: Amitryn poisoning treated with physostigmine. South Med J 1970;63:1492–1493.

Hollister LE, Overall JE, Johnson M, et al: Controlled comparison of Amitryn, imipramine and placebo in hospitalized depressed patients. J Nerv Ment Dis 1964;139:370–375.

Hordern A, Burt CG, Holt NF: Depressive states: A pharmacotherapeutic study, Springfield study. Springfield, Ill, Charles C. Thomas, 1965. Jenike MA: Treatment of Affective Illness in the Elderly with Drugs and Electroconvulsive Therapy. J Geriatr Psychiatry 1989; 22(1):77–112.

Klerman GL, Cole JO: Clinical pharmacology of imipramine and related antidepressant compounds. Int J Psychiatry 1976;3:267–304.

Liu B, Anderson G, Mittman N, et al: Use of selective serotonin-reuptake inhibitors or tricyclic antidepressants and risk of hip fractures in elderly people. Lancet 1998; 351(9112):1303–1307.

McConaghy N, Joffe AD, Kingston WA, et al: Correlation of clinical features of depressed out-patients with response to Amitryn and protriptyline. Br J Psychiatry 1968;114:103–106.

McDonald IM, Perkins M, Marjerrison G, et al: A controlled comparison of Amitryn and electroconvulsive therapy in the treatment of depression. Am J Psychiatry 1966;122:1427–1431.

Slovis T, Ott J, Teitelbaum D, et al: Physostigmine therapy in acute tricyclic antidepressant poisoning. Clin Toxicol 1971;4:451–459.

Symposium on depression with special studies of a new antidepressant, Amitryn. Dis Nerv Syst, (Sect 2) May 1961, pp 5–56.

*Based on a maximum recommended Amitryn dose of 150 mg/day or 3 mg/kg/day for a 50 kg patient.

**Hollister LE: Monitoring Tricyclic Antidepressant Plasma Concentrations. JAMA 1979; 241(23):2530–2533.

Amitryn 25 mg tablets are yellow, round, unscored, film coated tablets, debossed “2102” on one side and debossed “V” on the reverse side. They are supplied as follows: Bottles of 100: NDC 69874-422-10

Manufactured by: Qualitest Pharmaceuticals/Vintage Pharmaceuticals, Huntsville, AL 35811. Manufactured for: Thompson Medical Solutions, Birmingham, AL 35242. Revised: Apr 2016

See also:
What is the most important information I should know about Amitryn?

Amitryn hydrochloride is contraindicated in patients who have shown prior hypersensitivity to it.

It should not be given concomitantly with monoamine oxidase inhibitors. Hyperpyretic crises, severe convulsions, and deaths have occurred in patients receiving tricyclic antidepressant and monoamine oxidase inhibiting drugs simultaneously. When it is desired to replace a monoamine oxidase inhibitor with Amitryn hydrochloride, a minimum of 14 days should be allowed to elapse after the former is discontinued. Amitryn hydrochloride should then be initiated cautiously with a gradual increase in dosage until optimum response is achieved.

Amitryn hydrochloride should not be given with Cisapride due to the potential for increased QT interval and increased risk for arrhythmia.

This drug is not recommended for use during the acute recovery phase following myocardial infarction.

Use Amitryn as directed by your doctor. Check the label on the medicine for exact dosing instructions.

• Amitryn comes with an additional patient information sheet called a Medication Guide. Read it carefully and reread it each time you get Amitryn refilled.
• Amitryn may be taken with food or on an empty stomach.
• Amitryn may take up to 30 days to control symptoms of depression. Continue to use Amitryn even if you feel well. Do not miss any doses.
• If you miss a dose of Amitryn, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use Amitryn.

This medication is used to treat mental/mood problems such as depression. It may help improve mood and feelings of well-being, relieve anxiety and tension, help you sleep better, and increase your energy level. This medication belongs to a class of medications called tricyclic antidepressants. It works by affecting the balance of certain natural chemicals (neurotransmitters such as serotonin) in the brain.

OTHER USES: This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

This medication may also be used to treat nerve pain (such as peripheral neuropathy, postherpetic neuralgia), eating disorder (bulimia), other mental/mood problems (such as anxiety, panic disorder), or to prevent migraine headaches.

How to use Amitryn

Read the Medication Guide provided by your pharmacist before you start taking Amitryn and each time you get a refill. If you have any questions, consult your doctor or pharmacist.

Take this medication by mouth, usually 1 to 4 times daily or as directed by your doctor. If you take it only once a day, take it at bedtime to help reduce daytime sleepiness. The dosage is based on your medical condition and response to treatment.

To reduce your risk of side effects (such as drowsiness, dry mouth, dizziness), your doctor may direct you to start this medication at a low dose and gradually increase your dose. Follow your doctor's instructions carefully.

Take this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time(s) each day. Do not increase your dose or use this drug more often or for longer than prescribed. Your condition will not improve any faster, and your risk of side effects will increase.

It is important to continue taking this medication even if you feel well. Do not stop taking this medication without consulting your doctor. Some conditions may become worse when this drug is suddenly stopped. Also, you may experience symptoms such as mood swings, headache, tiredness, and sleep change. To prevent these symptoms while you are stopping treatment with this drug, your doctor may reduce your dose gradually. Consult your doctor or pharmacist for more details. Report any new or worsening symptoms right away.

This medication may not work right away. You may see some benefit within a week. However, it may take up to 4 weeks before you feel the full effect.

Tell your doctor if your condition persists or worsens (such as your feelings of sadness get worse, or you have thoughts of suicide).

See also:
What other drugs will affect Amitryn?

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug include: arbutamine, disulfiram, thyroid supplements, other drugs that can cause bleeding/bruising (including antiplatelet drugs such as clopidogrel, NSAIDs such as ibuprofen, "blood thinners" such as warfarin), anticholinergic drugs (such as benztropine, belladonna alkaloids), certain drugs for high blood pressure (drugs that work in the brain such as clonidine, guanabenz, reserpine).

Taking MAO inhibitors with this medication may cause a serious (possibly fatal) drug interaction. Avoid taking MAO inhibitors (isocarboxazid, linezolid, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, selegiline, tranylcypromine) during treatment with this medication. Most MAO inhibitors should also not be taken for two weeks before and after treatment with this medication. Ask your doctor when to start or stop taking this medication.

Other medications can affect the removal of Amitryn from your body, thereby affecting how Amitryn works. These drugs include cimetidine, terbinafine, drugs to treat irregular heart rate (such as quinidine/propafenone/flecainide), antidepressants (such as SSRIs including paroxetine/fluoxetine/fluvoxamine). This is not a complete list.

Many drugs besides Amitryn may affect the heart rhythm (QT prolongation in the EKG), including amiodarone, cisapride, dofetilide, pimozide, procainamide, quinidine, sotalol, macrolide antibiotics (such as erythromycin), among others. Therefore, before using Amitryn, report all medications you are currently using to your doctor or pharmacist.

Tell your doctor or pharmacist if you are taking other products that cause drowsiness, including alcohol, antihistamines (such as cetirizine, diphenhydramine), drugs for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants, and narcotic pain relievers (such as codeine).

Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain decongestants or ingredients that cause drowsiness. Ask your pharmacist about using those products safely.

Aspirin can increase the risk of bleeding when used with this medication. However, if your doctor has directed you to take low-dose aspirin for heart attack or stroke prevention (usually at dosages of 81-325 milligrams a day), you should continue taking it unless your doctor instructs you otherwise. Ask your doctor or pharmacist for more details.

Amitryn is very similar to nortriptyline. Do not use medications containing nortriptyline while using Amitryn.

See also:
What are the possible side effects of Amitryn?

Within each category the following adverse reactions are listed in order of decreasing severity. Included in the listing are a few adverse reactions which have not been reported with this specific drug. However, pharmacological similarities among the tricyclic antidepressant drugs require that each of the reactions be considered when Amitryn is administered.

Cardiovascular: Myocardial infarction; stroke; nonspecific ECG changes and changes in AV conduction; heart block; arrhythmias; hypotension, particularly orthostatic hypotension; syncope; hypertension; tachycardia; palpitation.

CNS and Neuromuscular: Coma; seizures; hallucinations; delusion; confusional states; disorientation; incoordination; ataxia; tremors; peripheral neuropathy; numbness, tingling and paresthesias of the extremities; extrapyramidal symptoms including abnormal involuntary movements and tardive dyskinesia; dysarthria; disturbed concentration; excitement; anxiety; insomnia; restlessness; nightmares; drowsiness; dizziness; weakness; fatigue; headache; syndrome of inappropriate ADH (antidiuretic hormone) secretion; tinnitus; alteration in EEG patterns.

Anticholinergic: Paralytic ileus; hyperpyrexia; urinary retention; dilatation of the urinary tract; constipation; blurred vision, disturbance of accommodation, increased ocular pressure, mydriasis; dry mouth.

Allergic: Skin rash; urticaria; photosensitization; edema of face and tongue.

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

Gastrointestinal: Rarely hepatitis (including altered liver function and jaundice); nausea; epigastric distress; vomiting; anorexia; stomatitis; peculiar taste; diarrhea; parotid swelling; black tongue.

Endocrine: Testicular swelling and gynecomastia in the male; breast enlargement and galactorrhea in the female; increased or decreased libido; impotence; elevation and lowering of blood sugar levels.

Other: Alopecia; edema; weight gain or loss; urinary frequency; increased perspiration.

Withdrawal Symptoms: After prolonged administration, abrupt cessation of treatment may produce nausea, headache, and malaise. Gradual dosage reductions have been reported to produce, within two weeks, transient symptoms including irritability, restlessness, and dream and sleep disturbance.

These symptoms are not indicative of addiction. Rare instances have been reported of mania or hypomania occurring within 2 to 7 days following cessation of chronic therapy with tricyclic antidepressants.

Causal Relationship Unknown: Other reactions, reported under circumstances where a causal relationship could not be established, are listed to serve as alerting information to physicians.

Body as a Whole: Lupus-like syndrome (migratory arthritis, positive ANA and rheumatoid factor).

Digestive: Hepatic failure, ageusia.

Postmarketing Adverse Events: A syndrome resembling neuroleptic malignant syndrome (NMS) has been very rarely reported after starting or increasing the dose of Amitryn hydrochloride, with and without concomitant medications known to cause NMS. Symptoms have included muscle rigidity, fever, mental status changes, diaphoresis, tachycardia, and tremor.

Very rare cases of serotonin syndrome (SS) have been reported with Amitryn hydrochloride in combination with other drugs that have a recognized association with SS.

Very rare cases of cardiomyopathy have been reported with Amitryn.