Drugs List

Therapeutic Indications

Uses

Chronic tension type headache: prophylaxis
Depression - severe
Migraine (prophylaxis)
Neuropathic pain
Nocturnal enuresis

Treatment of major depressive disorder in adults

Treatment of neuropathic pain in adults

Prophylactic treatment of chronic tension type headache (CTTH) in adults

Prophylactic treatment of migraine in adults

Treatment of nocturnal enuresis in children aged 6 years and above when organic pathology, including spina bifida and related disorders, have been excluded and no response has been achieved to all other non-drug and drug treatments, including antispasmodic and vasopressin related products.

Unlicensed Uses

Abdominal pain

Contraindications

Children under 16 years - if used for the treatment of depression
Children under 2 years
Within 2 weeks of discontinuing MAOIs
Within 2 weeks of discontinuing selegiline
Atrioventricular block
Cardiac arrhythmias
Congestive cardiac failure
Ischaemic heart disease
Long QT syndrome
Mania
Porphyria
Recent myocardial infarction
Severe hepatic impairment
Torsade de pointes

Precautions and Warnings

Anaesthesia
Children aged 2 to 5 years
Elderly
Electroconvulsive therapy
Family history of long QT syndrome
Predisposition to epileptic disorder
Suicidal ideation
Bipolar disorder
Breastfeeding
Cardiovascular disorder
Diabetes mellitus
Electrolyte imbalance
Epileptic disorder
Galactosaemia
Glucose-galactose malabsorption syndrome
Haematological disorder
Hereditary fructose intolerance
History of mania
History of seizures
History of torsade de pointes
History of urinary retention
Hyperthyroidism
Lactose intolerance
Mild hepatic impairment
Narrow angle glaucoma
Phaeochromocytoma
Pregnancy
Prostate disorder
Psychosis
Raised intra-ocular pressure
Schizophrenia
Thyroid dysfunction
Urinary retention

Correct electrolyte disorders before treatment
Patients at risk of suicide should be closely supervised
Patients with diabetes may experience fluctuations in blood glucose
Advise impaired alertness may affect ability to drive or operate machinery
Not all formulations are suitable for use in children under 18 years
Oral liquid contains hydroxybenzoate: caution in hypersensitivity
Oral solution with maltitol unsuitable in hereditary fructose intolerance
Some brands contain Quinoline Yellow (E104) : May cause allergic reactions
Some brands contain Sunset Yellow (E110) - can trigger allergic reactions
Some formulations contain lactose
Some formulations contain propylene glycol
Some formulations may contain alcohol
Consider monitoring ECG in patients at risk of QT prolongation
Dental check-ups advisable during long-term treatment
Monitor for depressive disorders/suicidal ideation-consider discontinuation
Monitor patients at risk of glaucoma for increases in intraocular pressure
Monitor serum electrolytes
Nocturnal enuresis - reassess need for treatment after 3 months
Reassess need for continued treatment at regular intervals of 3-6 months
Treatment of depression - monitor initially; may take 2-4 weeks to respond
Advise patient to report any new or worsening depression/suicidal ideation
Advise patients/carers to seek medical advice if suicidal intent develops
Aggressive behaviour may occur
Consider hyponatraemia in all patients with drowsiness/confusion/seizures
Increased risk of fractures in patients over 50 years
May aggravate anxiety and agitation
May exacerbate schizophrenia
Potential for withdrawal symptoms
Treatment of children with nocturnal enuresis-behavioural changes may occur
Avoid abrupt withdrawal
Discontinue prior to surgery
Reduce dose in elderly
Advise patient not to take St John's wort concurrently
Advise patient that the effects of alcohol may be potentiated

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 self harm is highest shortly after presentation and the risk of suicide may increase again in the early stages of recovery. Furthermore, there is evidence that in children and adolescents, antidepressants may increase the risk of suicidal thoughts and self harm

Other psychiatric conditions for which amitriptyline is prescribed can also be associated with an increased risk of suicide related events. In addition, these conditions may be co-morbid with major depressive disorder. The same precautions observed when treating patients with major depressive disorder should therefore be observed when treating patients with other psychiatric disorders.

Patients with a history of suicide related events, those exhibiting a significant degree of suicidal ideation prior to commencement of treatment, and young adults, are at a greater risk of suicidal thought or suicide attempt, and should receive careful monitoring during treatment.

Patients, (and caregivers of patients) should be alerted about the need to monitor for the emergence of suicidal thoughts and behaviour, and to seek medical advice immediately if these symptoms present. The antidepressant effects of amitriptyline may not be apparent for 2 to 4 weeks. Patients should be closely monitored during this period.

Where possible, amitriptyline should be discontinued several days before surgery. If this is not possible, caution should be observed as anaesthesia may increase the risk of hypotension and arrhythmias.

Pregnancy and Lactation

Pregnancy

Use amitriptyline hydrochloride with caution in pregnancy.

Tricyclic antidepressants (TCAs), along with SSRIs, are the drug group of choice for treating depression in pregnancy. According to the Clinical Knowledge Summaries, they are well established for the management of depression in pregnancy, and have been used for a long time. Extensive epidemiological studies have not shown evidence of a causal relationship between therapeutic doses of TCAs and an increased incidence of congenital malformations or other adverse pregnancy outcomes. Amitriptyline, nortriptyline and imipramine are preferred, having the lowest known risks during pregnancy as they are least sedative and have fewest maternal adverse effects.

There have been some reports of amitriptyline-induced teratogenicity in animals, but other studies in mice, rats and rabbits did not reveal any evidence of teratogenicity with oral doses of up to 13 times the maximum recommended human dose. Some reports of limb reduction anomalies in humans have been located, but an association with amitriptyline has not been confirmed. Briggs concludes that the bulk of evidence indicates that this widely used drug is relatively safe during pregnancy.

Maternal serum levels of TCAs should be monitored, with a view to possible dose adjustment, as pharmacokinetics may be altered especially in the second and third trimesters. The usual therapeutic dose may not be sufficient to keep the mother stable, and subtherapeutic levels of TCAs have been associated with relapse. Antidepressants should not be discontinued abruptly during pregnancy. However, as chronic use or use of high doses near to term have been associated with neonatal withdrawal symptoms, it may be appropriate to taper the dose 3 to 4 weeks before delivery. In this case, it is recommended that the pre-pregnancy dose should be resumed immediately after delivery to prevent relapse. If dose is not tapered, and use continues in the latter stages of pregnancy, particularly in the third trimester, the neonate should be observed carefully for at least 2 days after delivery for withdrawal symptoms including respiratory distress, jitteriness, irritability, tremor and feeding problems.

The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14 to 17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).

Lactation

Use amitriptyline hydrochloride with caution in breastfeeding.

Amitriptyline hydrochloride is excreated into the milk. However, the LactMed database states that milk levels of amitriptyline and metabolites are low, and immediate side effects have not been reported. Limited follow-up has found no adverse effects on infant growth and development. Furthermore, use during breastfeeding would not be expected to cause any adverse effects in breastfed infants, particularly if the infant is older than 2 months. Other antidepressants with fewer active metabolites may be preferred when large doses are required, or for newborn or preterm infants.

Imipramine and nortriptyline appear to be the drugs of choice during breastfeeding, according to the UK Drugs in Lactation Advisory Service Clinical Knowledge Summaries, but other TCAs are also acceptable with compelling indication (Schaefer, 2007). According to the Clinical Knowledge Summaries, all TCAs can be given safely to breastfeeding women, providing the infant is healthy and their progress is monitored. No short-term toxicity or long-term developmental effects have been demonstrated, but there is insufficient information on the long-term effects of antidepressants during breastfeeding. The effects of exposure to small amounts of amitriptyline in milk are unknown.

Where possible, medication should be taken as a single dose before the infant's longest sleep period. Advise mothers to breastfeed immediately before a dose, and avoid breastfeeding during peak levels (i.e. 1 to 3 hours after a dose). In very young infants who feed frequently, consider substituting a bottle feed to avoid peak levels. Avoid exposing premature or low birthweight infants to antidepressants via breast milk if at all possible. All infants should be monitored for drowsiness and other behavioural changes such as feeding difficulties, poor weight gain and restlessness.

Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
Specialist advice is available from the UK Drugs in Lactation Advisory Service at https://www.midlandsmedicines.nhs.uk/content.asp?section=6&subsection=17&pageIdx=1

Side Effects

Agranulocytosis
Alopecia
Anorexia
Anxiety
Arrhythmias
Ataxia
AV conduction disorders
Behavioural disturbances
Black tongue
Blood sugar changes
Blurred vision
Bone marrow depression
Breast enlargement
Changes in hepatic function
Changes in libido
Coma
Confusion
Constipation
Convulsions
Delirium
Delusions
Diarrhoea
Difficulty in micturition
Disorientation
Disturbances in accommodation
Dizziness
Drowsiness
Dry eyes
Dry mouth
Dysarthria
ECG changes
EEG changes
Eosinophilia
Epigastric distress
Excitement
Extrapyramidal effects
Facial oedema
Fatigue
Galactorrhoea
Glaucoma (closed angle)
Gynaecomastia
Hallucinations
Headache
Heart block
Hepatitis
Hyperpyrexia
Hypersensitivity reactions
Hypertension
Hypomania
Hyponatraemia
Hypotension
Impaired concentration
Impotence
Inappropriate secretion of antidiuretic hormone
Inco-ordination
Increased appetite
Increased intra-ocular pressure
Increased risk of fractures
Increased sweating
Insomnia
Involuntary movement disorders
Jaundice
Leucopenia
Mania
Mydriasis
Myocardial infarction
Nausea
Nightmares
Numbness
Palpitations
Paraesthesia in extremities
Paralytic ileus
Parotid swelling
Peripheral neuropathy
Photosensitivity
Postural hypotension
Purpura
Rash
Restlessness
Sedation
Sexual dysfunction
Stomatitis
Stroke
Suicidal tendencies
Syncope
Tachycardia
Tardive dyskinesia
Testicular swelling
Thrombocytopenia
Tinnitus
Tongue oedema
Tremor
Unpleasant taste
Urinary frequency
Urinary retention
Urinary tract dilatation
Urticaria
Vomiting
Weakness
Weight changes

Presentation

Oral preparations containing amitriptyline hydrochloride

Drugs List

Therapeutic Indications

Uses

Chronic tension type headache: prophylaxis
Depression - severe
Migraine (prophylaxis)
Neuropathic pain
Nocturnal enuresis

Treatment of major depressive disorder in adults

Treatment of neuropathic pain in adults

Prophylactic treatment of chronic tension type headache (CTTH) in adults

Prophylactic treatment of migraine in adults

Treatment of nocturnal enuresis in children aged 6 years and above when organic pathology, including spina bifida and related disorders, have been excluded and no response has been achieved to all other non-drug and drug treatments, including antispasmodic and vasopressin related products.

Unlicensed Uses

Abdominal pain

Dosage

Adults

Elderly

Children

Additional Dosage Information

Contraindications

Children under 16 years - if used for the treatment of depression
Children under 2 years
Within 2 weeks of discontinuing MAOIs
Within 2 weeks of discontinuing selegiline
Atrioventricular block
Cardiac arrhythmias
Congestive cardiac failure
Ischaemic heart disease
Long QT syndrome
Mania
Porphyria
Recent myocardial infarction
Severe hepatic impairment
Torsade de pointes

Precautions and Warnings

Anaesthesia
Children aged 2 to 5 years
Elderly
Electroconvulsive therapy
Family history of long QT syndrome
Predisposition to epileptic disorder
Suicidal ideation
Bipolar disorder
Breastfeeding
Cardiovascular disorder
Diabetes mellitus
Electrolyte imbalance
Epileptic disorder
Galactosaemia
Glucose-galactose malabsorption syndrome
Haematological disorder
Hereditary fructose intolerance
History of mania
History of seizures
History of torsade de pointes
History of urinary retention
Hyperthyroidism
Lactose intolerance
Mild hepatic impairment
Narrow angle glaucoma
Phaeochromocytoma
Pregnancy
Prostate disorder
Psychosis
Raised intra-ocular pressure
Schizophrenia
Thyroid dysfunction
Urinary retention

Correct electrolyte disorders before treatment
Patients at risk of suicide should be closely supervised
Patients with diabetes may experience fluctuations in blood glucose
Advise impaired alertness may affect ability to drive or operate machinery
Not all formulations are suitable for use in children under 18 years
Oral liquid contains hydroxybenzoate: caution in hypersensitivity
Oral solution with maltitol unsuitable in hereditary fructose intolerance
Some brands contain Quinoline Yellow (E104) : May cause allergic reactions
Some brands contain Sunset Yellow (E110) - can trigger allergic reactions
Some formulations contain lactose
Some formulations contain propylene glycol
Some formulations may contain alcohol
Consider monitoring ECG in patients at risk of QT prolongation
Dental check-ups advisable during long-term treatment
Monitor for depressive disorders/suicidal ideation-consider discontinuation
Monitor patients at risk of glaucoma for increases in intraocular pressure
Monitor serum electrolytes
Nocturnal enuresis - reassess need for treatment after 3 months
Reassess need for continued treatment at regular intervals of 3-6 months
Treatment of depression - monitor initially; may take 2-4 weeks to respond
Advise patient to report any new or worsening depression/suicidal ideation
Advise patients/carers to seek medical advice if suicidal intent develops
Aggressive behaviour may occur
Consider hyponatraemia in all patients with drowsiness/confusion/seizures
Increased risk of fractures in patients over 50 years
May aggravate anxiety and agitation
May exacerbate schizophrenia
Potential for withdrawal symptoms
Treatment of children with nocturnal enuresis-behavioural changes may occur
Avoid abrupt withdrawal
Discontinue prior to surgery
Reduce dose in elderly
Advise patient not to take St John's wort concurrently
Advise patient that the effects of alcohol may be potentiated

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 self harm is highest shortly after presentation and the risk of suicide may increase again in the early stages of recovery. Furthermore, there is evidence that in children and adolescents, antidepressants may increase the risk of suicidal thoughts and self harm

Other psychiatric conditions for which amitriptyline is prescribed can also be associated with an increased risk of suicide related events. In addition, these conditions may be co-morbid with major depressive disorder. The same precautions observed when treating patients with major depressive disorder should therefore be observed when treating patients with other psychiatric disorders.

Patients with a history of suicide related events, those exhibiting a significant degree of suicidal ideation prior to commencement of treatment, and young adults, are at a greater risk of suicidal thought or suicide attempt, and should receive careful monitoring during treatment.

Patients, (and caregivers of patients) should be alerted about the need to monitor for the emergence of suicidal thoughts and behaviour, and to seek medical advice immediately if these symptoms present. The antidepressant effects of amitriptyline may not be apparent for 2 to 4 weeks. Patients should be closely monitored during this period.

Where possible, amitriptyline should be discontinued several days before surgery. If this is not possible, caution should be observed as anaesthesia may increase the risk of hypotension and arrhythmias.

Pregnancy and Lactation

Pregnancy

Use amitriptyline hydrochloride with caution in pregnancy.

Tricyclic antidepressants (TCAs), along with SSRIs, are the drug group of choice for treating depression in pregnancy. According to the Clinical Knowledge Summaries, they are well established for the management of depression in pregnancy, and have been used for a long time. Extensive epidemiological studies have not shown evidence of a causal relationship between therapeutic doses of TCAs and an increased incidence of congenital malformations or other adverse pregnancy outcomes. Amitriptyline, nortriptyline and imipramine are preferred, having the lowest known risks during pregnancy as they are least sedative and have fewest maternal adverse effects.

There have been some reports of amitriptyline-induced teratogenicity in animals, but other studies in mice, rats and rabbits did not reveal any evidence of teratogenicity with oral doses of up to 13 times the maximum recommended human dose. Some reports of limb reduction anomalies in humans have been located, but an association with amitriptyline has not been confirmed. Briggs concludes that the bulk of evidence indicates that this widely used drug is relatively safe during pregnancy.

Maternal serum levels of TCAs should be monitored, with a view to possible dose adjustment, as pharmacokinetics may be altered especially in the second and third trimesters. The usual therapeutic dose may not be sufficient to keep the mother stable, and subtherapeutic levels of TCAs have been associated with relapse. Antidepressants should not be discontinued abruptly during pregnancy. However, as chronic use or use of high doses near to term have been associated with neonatal withdrawal symptoms, it may be appropriate to taper the dose 3 to 4 weeks before delivery. In this case, it is recommended that the pre-pregnancy dose should be resumed immediately after delivery to prevent relapse. If dose is not tapered, and use continues in the latter stages of pregnancy, particularly in the third trimester, the neonate should be observed carefully for at least 2 days after delivery for withdrawal symptoms including respiratory distress, jitteriness, irritability, tremor and feeding problems.

The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14 to 17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).

Lactation

Use amitriptyline hydrochloride with caution in breastfeeding.

Amitriptyline hydrochloride is excreated into the milk. However, the LactMed database states that milk levels of amitriptyline and metabolites are low, and immediate side effects have not been reported. Limited follow-up has found no adverse effects on infant growth and development. Furthermore, use during breastfeeding would not be expected to cause any adverse effects in breastfed infants, particularly if the infant is older than 2 months. Other antidepressants with fewer active metabolites may be preferred when large doses are required, or for newborn or preterm infants.

Imipramine and nortriptyline appear to be the drugs of choice during breastfeeding, according to the UK Drugs in Lactation Advisory Service Clinical Knowledge Summaries, but other TCAs are also acceptable with compelling indication (Schaefer, 2007). According to the Clinical Knowledge Summaries, all TCAs can be given safely to breastfeeding women, providing the infant is healthy and their progress is monitored. No short-term toxicity or long-term developmental effects have been demonstrated, but there is insufficient information on the long-term effects of antidepressants during breastfeeding. The effects of exposure to small amounts of amitriptyline in milk are unknown.

Where possible, medication should be taken as a single dose before the infant's longest sleep period. Advise mothers to breastfeed immediately before a dose, and avoid breastfeeding during peak levels (i.e. 1 to 3 hours after a dose). In very young infants who feed frequently, consider substituting a bottle feed to avoid peak levels. Avoid exposing premature or low birthweight infants to antidepressants via breast milk if at all possible. All infants should be monitored for drowsiness and other behavioural changes such as feeding difficulties, poor weight gain and restlessness.

Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
Specialist advice is available from the UK Drugs in Lactation Advisory Service at https://www.midlandsmedicines.nhs.uk/content.asp?section=6&subsection=17&pageIdx=1

Side Effects

Agranulocytosis
Alopecia
Anorexia
Anxiety
Arrhythmias
Ataxia
AV conduction disorders
Behavioural disturbances
Black tongue
Blood sugar changes
Blurred vision
Bone marrow depression
Breast enlargement
Changes in hepatic function
Changes in libido
Coma
Confusion
Constipation
Convulsions
Delirium
Delusions
Diarrhoea
Difficulty in micturition
Disorientation
Disturbances in accommodation
Dizziness
Drowsiness
Dry eyes
Dry mouth
Dysarthria
ECG changes
EEG changes
Eosinophilia
Epigastric distress
Excitement
Extrapyramidal effects
Facial oedema
Fatigue
Galactorrhoea
Glaucoma (closed angle)
Gynaecomastia
Hallucinations
Headache
Heart block
Hepatitis
Hyperpyrexia
Hypersensitivity reactions
Hypertension
Hypomania
Hyponatraemia
Hypotension
Impaired concentration
Impotence
Inappropriate secretion of antidiuretic hormone
Inco-ordination
Increased appetite
Increased intra-ocular pressure
Increased risk of fractures
Increased sweating
Insomnia
Involuntary movement disorders
Jaundice
Leucopenia
Mania
Mydriasis
Myocardial infarction
Nausea
Nightmares
Numbness
Palpitations
Paraesthesia in extremities
Paralytic ileus
Parotid swelling
Peripheral neuropathy
Photosensitivity
Postural hypotension
Purpura
Rash
Restlessness
Sedation
Sexual dysfunction
Stomatitis
Stroke
Suicidal tendencies
Syncope
Tachycardia
Tardive dyskinesia
Testicular swelling
Thrombocytopenia
Tinnitus
Tongue oedema
Tremor
Unpleasant taste
Urinary frequency
Urinary retention
Urinary tract dilatation
Urticaria
Vomiting
Weakness
Weight changes

Overdosage

It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

The following number will direct the caller to the relevant local centre (0844) 892 0111

Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).

The MHRA have produced 'generic' overdose sections for the top ten drugs for which the NPIS received the greatest number of queries about management of overdose in 2002. This information is attached below:

Ingestion of 750 mg or more by an adult may result in severe toxicity. The effects in overdose will be potentiated by simultaneous ingestion of alcohol and other psychotropic drugs.

Overdose effects are mainly due to anticholinergic (atropine-like) effects at autonomic nerve endings and in the brain. There is also a quinidine-like effect on the myocardium.

Signs and Symptoms

Peripheral symptoms:
Commonly include sinus tachycardia, hot dry skin, dry mouth and tongue, dilated pupils and urinary retention. The most important ECG feature of toxicity is prolongation of the QRS interval, which indicates a high risk of ventricular tachycardia. In very severe poisoning the ECG may be bizarre. Rarely, prolongation of the PR interval or heart block may occur. QT interval prolongation and torsade de pointes has also been reported. Central symptoms:
Commonly include ataxia, nystagmus and drowsiness, which may lead to deep coma and respiratory depression. Increased tone and hyperreflexia may be present with extensor plantar reflexes. In deep coma all reflexes may be abolished. A divergent squint may be present. Hypotension and hypothermia may occur. Fits occur in over 5% of cases. During recovery confusion, agitation and visual hallucinations may occur.

Treatment

An ECG should be taken and in particular the QRS interval should be assessed since prolongation signifies an increased risk of arrhythmia and convulsions. Give activated charcoal by mouth or naso-gastric tube if more than 4 mg/kg has been ingested within one hour, provided the airway can be protected. A second dose of charcoal should be considered after two hours in patients with central features of toxicity who are able to swallow. Tachyarrhythmias are best treated by correction of hypoxia and acidosis. Even in the absence of acidosis 50 millimoles of sodium bicarbonate should be given by intravenous infusion to adults with arrhythmias or clinically significant QRS prolongation on the ECG. Control convulsions with intravenous diazepam or lorazepam. Give oxygen and correct acid base and metabolic disturbances. Phenytoin is contraindicated in tricyclic overdosage, because, like tricyclic antidepressants, it blocks sodium channels and may increase the risk of cardiac arrhythmias. Glucagon has been used to correct myocardial depression and hypotension.

Further Information

Last Full Review Date: November 2014

Reference Sources

Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 2nd edition (2007) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 9th edition (2011) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.

Summary of Product Characteristics: Amitriptyline oral solution 10mg/5ml. Wockhardt UK Ltd. Revised August 2014
Summary of Product Characteristics: Amitriptyline oral solution 25mg/5ml. Rosemont Pharmaceuticals. Revised July 2013
Summary of Product Characteristics: Amitriptyline oral solution 50mg/5ml. Rosemont Pharmaceuticals. Revised July 2013

Summary of Product Characteristics: Amitriptyline tablets 10mg. Actavis UK Ltd. Revised March 2011
Summary of Product Characteristics: Amitriptyline tablets 25mg. Actavis UK Ltd. Revised March 2014
Summary of Product Characteristics: Amitriptyline tablets 50mg. Actavis UK Ltd. Revised March 2011

Clinical Knowledge Summaries - Depression: antenatal and postnatal
Available at: https://cks.nice.org.uk/depression-antenatal-and-postnatal
Last accessed: 26 May, 2015

MHRA 4th February 2008
https://www.mhra.gov.uk/NewsCentre/Pressreleases/CON2033960
Last accessed: 26 May, 2015

MHRA 22nd January 2007
https://www.mhra.gov.uk/Howweregulate/Medicines/Licensingofmedicines/Informationforlicenceapplicants/Guidance/OverdosesectionsofSPCs/Genericoverdosesections/Amitriptyline/index.htm
Last accessed: 26 May, 2015

MHRA Drug Safety Update May 2010
https://www.mhra.gov.uk
Last accessed: 26 May, 2015

NICE - Evidence Services
Available at: www.nice.org.uk
Last accessed: 14 September 2018

UK Drugs in Lactation Advisory Service.
Available at: https://www.midlandsmedicines.nhs.uk/content.asp?section=6&subsection=17&pageIdx=1
Last accessed: 26 May, 2015

US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
Available at: https://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT
Amytriptyline Last revised: 10 March, 2015
Last accessed: 26 May, 2015