Amitriptyline 25mg Tablets
Out of date information, search anotherSUMMARY OF PRODUCT CHARACTERISTICS
1 NAME OF THE MEDICINAL PRODUCT
Amitriptyline 25 mg Tablets
2 QUALITATIVE AND QUANTITATIVE COMPOSITION
Each tablet contains 25 mg of Amitriptyline Hydrochloride Ph. Eur.
Also contains lactose. For excipients, see 6.1.
3 PHARMACEUTICAL FORM
Film-coated Tablet
Yellow, biconvex, film coated tablets, engraved D on one side and plain on the reverse
4 CLINICAL PARTICULARS
4.1 Therapeutic indications
Amitriptyline is indicated for the treatment of depression, especially when sedation is required.
4.2 Posology and method of administration
For oral administration
Adults
Initially 75mg/day in divided doses or as a single dose at night, increasing to 150mg/day according to clinical response, the additional doses being given in the late afternoon and/or at bedtime.
The sedative effect is usually rapidly apparent, however the antidepressant effect may be apparent within three to four days or may take up to 30 days to develop adequately.
Maintenance dose is usually 50-100mg a day given as a single dose preferably in the evening or at bedtime. When a satisfactory improvement is achieved, the dosage should be reduced to the lowest effective dose which maintains the relief of symptoms. Maintenance therapy should be continued for at least three months to reduce the likelihood of relapse.
Children
Amitriptyline should not be used for children under 16 years of age.
Elderly
10-25mg three times a day is recommended initially, and this should be increased slowly. 50mg a day may be satisfactory in the elderly, who may not tolerate higher doses. The dosage may be taken as divided doses, or as a single dose, preferably in the evening or at bedtime.
4.3 Contraindications
• hypersensitivity to tricyclic antidepressants or to any of the ingredients in the tablets
• patients who are taking monoamine oxidase inhibitors (MAOIs) or who have taken them within the last 14 days;
• a history of myocardial infarction, arrhythmias, particularly heart block of any degree, congestive heart failure, coronary artery insufficiency;
• severe liver disease;
• children under 16 years;
• during breast-feeding (see section 4.6);
• mania
4.4 Special warnings and precautions for use
Amitriptyline should be used with great caution in patients with a history of epilepsy or recent convulsions, porphyria, phaeochromocytoma, impaired liver function, blood dyscrasias, urinary retention, symptoms suggestive of prostatic hypertrophy, narrow angle glaucoma, or increased intra-ocular pressure. In patients with narrow angle glaucoma, even average doses may precipitate an attack of glaucoma.
Patients with hyperthyroidism, cardiovascular disorders, and patients receiving thyroid hormone medication or anticholinergic agents may need the dosage of all medications carefully adjusted when amitriptyline is given concurrently (see section 4.5).
Cardiac arrhythmias and severe hypotension are likely to occur with high dosages or in patients with pre-existing heart disease.
If possible amitriptyline therapy should be discontinued several days before surgery, but if emergency surgery is required, the anaesthetist should be informed that the patient is taking amitriptyline as anaesthetics may increase the risk of arrhythmias and hypotension (see section 4.5).
Hyperpyrexia has been reported when tricyclic antidepressants are administered with anticholinergic agents or neuroleptic drugs, especially in hot weather.
The elderly or debilitated are particularly liable to experience toxic effects, especially agitation, confusion and postural hypotension. The initial dose should be increased with great caution under close supervision.
Hyponatraemia (usually in the elderly and possibly due to inappropriate secretion of antidiuretic hormone) should be considered in all patients who develop drowsiness, confusion or convulsions while taking an antidepressant.
When amitriptyline is given for the depressive component of schizophrenia, psychotic symptoms may be aggravated. In manic-depressives, a shift towards the manic phase may occur; paranoid delusions, with or without associated hostility, may be aggravated. In these cases, a major tranquilliser should be given concurrently, or the dosage of amitriptyline reduced.
Suicide/suicidal thoughts or clinical worsening
Depression is associated with an increased risk of suicidal thoughts, self harm and suicide (suicide-related events). This risk persists until significant remission occurs. As improvement may not occur during the first few weeks or more of treatment, patients should be closely monitored until such improvement occurs. It is general clinical experience that the risk of suicide may increase in the early stages of recovery.
Patients with a history of suicide-related events, or those exhibiting a significant degree of suicidal ideation prior to commencement of treatment are known to be at greater risk of suicidal thoughts or suicide attempts, and should receive careful monitoring during treatment. A meta-analysis of placebo-controlled clinical trials of antidepressant drugs in adult patients with psychiatric disorders showed an increased risk of suicidal behaviour with antidepressants compared to placebo in patients less than 25 years old.
Close supervision of patients and in particular those at high risk should accompany drug therapy especially in early treatment and following dose changes. Patients (and caregivers of patients) should be alerted about the need to monitor for any clinical worsening, suicidal behaviour or thoughts and unusual changes in behaviour and to seek medical advice immediately if these symptoms present.
This product contains the excipient, lactose. Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.
4.5 Interaction with other medicinal products and other forms of interaction
Altretamine: there is a risk of severe postural hypotension when amitriptyline and altretamine are used concurrently.
Alpha2-adrenoceptor stimulants: Concomitant use of apraclonidine and brimonidine should be avoided.
Analgesics: nefopam side effects may be increased; the risk of convulsions with tramadol may possibly be increased. Levacetylmethadol should not be used concomitantly with amitriptyline due to the increased risk of ventricular arrhythmias.
Anaesthetics: anaesthetics may increase the risk of arrhythmias and hypotension in patients taking amitriptyline (see section 4.4)
Antiarrhythmics: there is an increased risk of ventricular arrhythmias with drugs which prolong the QT interval, including amiodarone (avoid concomitant use), disopyramide, procainamide, propafenone and quinidine.
Antibacterials: the plasma concentrations of some tricyclic antidepressants may be reduced by rifampicin, leading to a reduced antidepressant effect. Concomitant use with linezolid may result in CNS excitation and hypertension.
Antidepressants: Concomitant use of reboxetine should be with caution. The plasma concentrations of some tricyclics are increased by SSRIs.
Fluoxetine markedly inhibits Cytochrome P450 II D6, which is involved in the metabolism of a number of tricyclic antidepressants. Patients should be monitored for increased antidepressant plasma levels and toxicity when fluoxetine is used concurrently. Adjustment of the antidepressant dosage may be necessary.
Anti epileptics: amitriptyline may antagonise antiepileptics e.g. barbiturates, carbamazepine thereby reducing the convulsive threshold. The plasma concentrations of some tricyclics may be reduced resulting in a reduced antidepressant effect.
Antihistamines: antimuscarinic and sedative effects may be increased. Avoid concomitant use with terfenadine as the risk of ventricular arrhythmias may be increased.
Antihypertensives: in general the hypotensive effect is enhanced, however, amitriptyline may decrease the antihypertensive effect of guanethidine, debrisoquine, bethanidine and possibly clonidine. There is an increased risk of hypertension on withdrawal of clonidine. It is advisable to review all antihypertensive therapy during treatment with tricyclic antidepressants.
Antimuscarinics: antimuscarinic side effects may be increased. Paralytic ileus, urinary retention or acute glaucoma may occur in patients taking tricyclic antidepressants concurrently with drugs having an anticholinergic action, especially in elderly patients.
Antipsychotics: the risk of ventricular arrhythmias is increased (avoid concomitant use with pimozide or thioridazine); plasma concentrations of some tricyclics are increased. Antimuscarinic side effects may be increased with phenothiazines and possibly clozapine.
Antivirals: Based on the known metabolism of amitriptyline, the protease inhibitor, ritonavir, may increase the serum levels of amitriptyline. Therefore, careful monitoring of therapeutic and adverse effects is recommended when these drugs are administered concomitantly.
Anxiolytics and hypnotics: Concomitant use enhances the sedative effect.
Other CNS Depressants: amitriptyline may potentiate the central nervous depressant action of alcohol, barbiturates, and other CNS depressants. In turn, the antidepressant action of amitriptyline may be decreased by barbiturates. Caution is also advised in patients who receive large doses of ethchlorvynol concurrently with amitriptyline, as transient delirium has been reported in patients receiving 1 g ethchlorvynol and 75 - 150 mg of amitriptyline.
Beta-blockers: the risk of ventricular arrhythmias associated with sotalol is increased.
Calcium-channel Blockers: diltiazem and verapamil may increase the plasma concentration of amitriptyline.
Disulfiram: Delirium has been reported in patients taking amitriptyline with disulfiram. Concomitant use may inhibit the metabolism of tricyclics.
Increased plasma concentrations and increased disulfiram reaction has been reported in patients taking amitriptyline, alcohol and disulfiram concomitantly.
Diuretics: there is an increased risk of postural hypotension.
Dopaminergics: Concomitant use with entacapone should be avoided. CNS toxicity has been reported with selegiline.
Monoamine oxidase inhibitors (MAOIs): MAOIs can potentiate the effects of amitriptyline, and cases of hyperpyretic crises, severe convulsions and fatalities have been reported. Amitriptyline should not be given with and until a minimum of two weeks after discontinuing treatment with a monoamine oxidase inhibitor. The amitriptyline should be introduced cautiously and the dosage increased gradually. CNS excitation and hypertension have occurred with MAOIs.
Muscle Relaxants: the muscle relaxant effect of baclofen may be enhanced by concomitant use.
Nitrates: the effect of sublingual nitrates may be reduced (owing to the effect of dry mouth).
Oestrogens and Progestogens: oral contraceptives antagonise the antidepressant effect but side effects may be increased due to the increased plasma concentration of amitriptyline.
Ritonavir: based on the known metabolism of amitriptyline, the protease inhibitor ritonavir may increase the serum levels of amitriptyline. Therefore careful monitoring of therapeutic and adverse effects is recommended when these drugs are administered concomitantly.
Sibutramine: Concomitant use is not recommended due to the increased risk of CNS toxicity.
Sympathomimetic Agents: amitriptyline should not be given with sympathomimetic agents such as adrenaline, ephedrine, isoprenaline, noradrenaline, phenylephrine and phenylpropanolamine due to hypertension and arrhythmias. Local anaesthetics with adrenaline appear to be safe. Methylphenidate may inhibit the metabolism of tricyclics and therefore increase the antidepressant action of amitriptyline.
Thyroid preparations e.g. levothyroxine: the action of tricyclic antidepressants such as amitriptyline may be accelerated by the concurrent use of thyroid hormone medication (see section 4.4, Special Warnings and Special Precautions for Use).
Ulcer-healing Drugs: cimetidine is reported to reduce hepatic metabolism of certain tricyclic antidepressants when taken concurrently resulting in increased plasma concentration of amitriptyline.
Concurrent administration of amitriptyline with electroconvulsive therapy should be limited to patients for whom it is considered essential, as the hazards of each treatment may be increased.
4.6 Pregnancy and lactation
Safety in pregnancy and lactation has not been established. Do not use during the first and third trimester or in nursing mothers unless there are compelling reasons. Clinical experience of the use of amitriptyline in pregnancy is limited. Animal studies have shown harmful effects at exceptionally high doses. Withdrawal symptoms, including respiratory depression and agitation have been reported in neonates whose mothers had taken tricyclic antidepressants during the last trimester of pregnancy. Urinary retention in the neonate has also been associated with maternal use of amitriptyline.
Amitriptyline is detectable in breast milk. Because of the potential risk of serious adverse reactions to breast-fed infants, a decision should be made to either discontinue amitriptyline or breast-feeding.
4.7 Effects on ability to drive and use machines
Drowsiness (impaired alertness) is not uncommon in the early stages of treatment and patients should be warned not to drive or operate machinery until it has been established that their alertness is not impaired.
4.8 Undesirable effects
In general, amitriptyline is well tolerated. The following adverse effects although not necessarily all reported with amitriptyline, have occurred with tricyclic antidepressants.
Blood and lymphatic system disorders: bone marrow depression including agranulocytosis, leucopenia, eosinophilia, purpura, and thrombocytopenia.
Immune system disorders: Allergic reactions, oedema of the face and tongue.
Endocrine disorders: syndrome of inappropriate ADH (antidiuretic hormone) secretion (see section 4.4).
Metabolism and nutrition disorders: increased appetite and weight gain may be a drug reaction or due to relief of depression.
Psychiatric disorders: confusional states, disorientation, delusions, hallucinations, hypomania, excitement, anxiety, restlessness, drowsiness, insomnia, nightmares.
Cases of suicidal ideation and suicidal behaviours have been reported during amitriptyline therapy or early after treatment discontinuation (see section 4.4).
Nervous system disorders: Dizziness, headache, drowsiness, disturbed concentration, numbness, tingling and paraesthesiae of the extremities, peripheral neuropathy, incoordination, ataxia, tremors, coma, convulsions, alteration of the EEG, extrapyramidal symptoms, including abnormal involuntary movements and tardive dyskinesia, dysarthria.
Ear and labyrinth disorders: tinnitus
Anticholinergic effects reported are dry mouth, blurred vision, mydriasis, disturbance of accommodation, increased intra-ocular pressure, constipation, paralytic ileus, hyperpyrexia, urinary retention, and urinary tract dilatation.
Cardiac disorders: syncope, tachycardia, palpitations, myocardial infarction, arrhythmias, heart block, stroke, and non-specific ECG changes in AV conduction. Cardiac arrhythmias and severe hypotension are likely to occur with high dosage or in deliberate overdosage. They may also occur in patients with pre-existing heart disease taking normal dosage.
Vascular disorders: hypotension, postural hypotension, hypertension
Gastrointestinal disorders: nausea, epigastric distress, vomiting, anorexia, stomatitis, taste disturbance, diarrhoea, parotid swelling, black tongue.
Hepato-biliary disorders: Rarely hepatitis (including altered liver function and jaundice).
Skin and subcutaneous tissue disorders: skin rash, urticaria, photosensitisation, increased perspiration and alopecia.
Renal and urinary disorders: Urinary frequency.
Reproductive system and breast disorders: testicular swelling, gynaecomastia, breast enlargement, galactorrhoea, increased or decreased libido, impotence, interference with sexual function.
General disorders and administration site conditions: fatigue, weakness
Investigations: elevation or lowering of blood sugar levels, weight gain may be a drug reaction or due to relief of depression
Confusion may occur at high doses or in elderly patients requiring reduction of dosage.
Withdrawal symptoms which may occur on abrupt cessation of therapy include nausea, headache and malaise. Gradual withdrawal is associated with reports of transient symptoms including irritability, restlessness, as well as dream and sleep disturbances during the first two weeks of dosage reduction. These symptoms are not indicative of addiction.
There have also been reports of withdrawal symptoms, respiratory depression and agitation in neonates, whose mothers received tricyclic antidepressants.
Mania or hypomania has been reported rarely within 2 - 7 days of stopping chronic treatment with tricyclic antidepressants.
Class effects
Epidemiological studies, mainly conducted in patients 50 years of age and older, show an increased risk of bone fractures in patients receiving SSRIs and TCAs. The mechanism leading to this risk is unknown.
4.9 Overdose
High dosage may cause transient visual hallucinations, temporary confusion and disturbed concentration. Overdosage may cause tachycardia, other arrhythmic abnormalities such as bundle branch block, ECG evidence of impaired conduction, congestive heart failure, severe hypotension, dilated pupils, drowsiness, hypothermia, convulsions, stupor and coma. Other symptoms may include agitation, hyperactive reflexes, muscle rigidity, vomiting, hyperpyrexia, or any of the other side effects listed previously.
There is no specific antidote for tricyclic antidepressant poisoning. Patients should be hospitalised and treatment should be symptomatic and based on cardiac (including ECG monitoring) and respiratory support.
The stomach should be emptied as quickly as possible by emesis, followed by gastric lavage and aspiration. Following lavage, activated charcoal at a dose of 20-30g every four to six hours may be given for the first 24-48 hours. An open airway and an adequate fluid intake should be maintained, and body temperature regulated.
Intravenous physostigmine salicylate, 1-3mg has been reported to reverse the symptoms of tricyclic antidepressant poisoning. As physostigmine is rapidly metabolised, the dosage should be repeated as required, particularly if life-threatening signs such as arrhythmias, convulsions and deep coma recur or persist after the initial dose. As physostigmine itself may be toxic, it is not recommended for routine use.
Standard measures should be used to manage circulatory shock and metabolic acidosis. Cardiac arrhythmias may be treated with neostigmine, pyridostigmine or propranolol. Should cardiac failure occur, use of digitalis should be considered. Close monitoring of cardiac function for not less than five days is advisable.
If convulsions occur, they should be treated with paraldehyde, diazepam or an inhalation anaesthetic. Barbiturates should not be used because amitriptyline increases their CNS-depressant action.
Dialysis is of no value because of low plasma concentrations of amitriptyline.
Since overdosage is often deliberate, patients may attempt suicide by other means during the recovery phase. Deaths by deliberate or accidental overdosage have occurred with this class of medicament.
5 PHARMACOLOGICAL PROPERTIES
5.1 Pharmacodynamic properties
ATC Code: NO6A AO9 Antidepressants
Amitriptyline is a tricyclic antidepressant. These drugs block the re-uptake of noradrenaline and serotonin (5HT) into presynaptic nerve terminals and this has been thought to be their mode of action. However the antidepressant effect does not appear until 10-14 days after starting treatment whereas a block in activity can be shown within an hour. This suggests that other pharmacological actions may also contribute.
5.2 Pharmacokinetic properties
Amitriptyline is readily absorbed from the GI tract, peak plasma levels occurring within approximately 6 hours of oral administration. The bioavailability of amitriptyline is 48 ± 11%, it is 94.8 ± 0.8% plasma bound. Neither parameter is age dependant. Half-life is 16 ± 6 hours with a volume of distribution of 14 ± 2 L/kg. Both of these parameters will significantly increase with age.
Amitriptyline is extensively demethylated in the liver to its primary metabolite, nortriptyline. Paths of metabolism include hydroxylation, N-oxidation and conjugation with glucuronic acid. It is excreted in the urine, mainly in the form of its metabolites, either free or in conjugated form. Clearance is 12.5 ± 2.8ml/min/kg (not age dependant) and less than 2% in excreted in the urine.
5.3 Preclinical safety data
Preclinical information has not been included because the safety profile of amitriptyline has been established after many years of clinical use. Please refer to section 4.
6 PHARMACEUTICAL PARTICULARS
6.1 List of excipients
Tablet core:
Lactose monohydrate Maize starch
Calcium hydrogen phosphate dihydrate Silica colloidal anhydrous Magnesium stearate Sunset yellow (E110)
Tablet coating:
Hypromellose (E464)
Polyethylene glycol Quinoline yellow (E104)
Titanium dioxide (E171)
Carnauba wax
6.2 Incompatibilities
None known
6.3 Shelf life
Blister strips: 36 months
Polypropylene containers with caps/child resistant caps: 36 months HDPE containers with caps/child resistant caps: 36 months Polythene buckets: 60 months
Amber glass bottles with plastic screw caps: 24 months
6.4 Special precautions for storage
No special storage precautions
6.5 Nature and contents of container
Blister strips in packs of 7, 10, 14, 21, 28, 30, 56, 60, 84, 90, 100, 110, 112, 120, 150, 160 or 168 tablets with a shelf life of 36 months.
Polypropylene containers with caps or child resistant caps, in pack sizes of 500 tablets with a shelf life of 36 months.
HDPE containers with caps or child resistant caps, in pack sizes of 25 or 500 tablets with a shelf-life of 36 months.
Polythene buckets containing 15000 tablets with a shelf life of 60 months.
Amber glass bottles with plastic screw caps, in a pack size of 25 tablets with a shelf life of 24 months.
Not all pack sizes may be marketed.
6.6 Special precautions for disposal
Not applicable
7 MARKETING AUTHORISATION HOLDER
TEVA UK Limited Brampton Road Hampden Park Eastbourne East Sussex BN22 9AG
8 MARKETING AUTHORISATION NUMBER(S)
PL 00289/0179
9 DATE OF FIRST AUTHORISATION/RENEWAL OF THE AUTHORISATION
22/07/1991
10 DATE OF REVISION OF THE TEXT
12/12/2012