Atropine

Registered South African indications: 

• Pre-operatively, to counteract the vagal effects that may frequently occur during anaesthesia
• Neuromuscular blockade reversal adjunct
• Initial treatment of acute myocardial infarction where excessive vagal tone causes sinus or nodal bradycardia
• Muscarinic toxicity or poisoning by organophosphate cholinesterase inhibitors or cholinomimetic alkaloid muscarine

Contraindications 

• Hypersensitivity to the active ingredient or any of its excipients
• Myasthenia gravis (except when given with an anticholinesterase)
• Paralytic ileus
• Pyloric stenosis
• Toxic megacolon
• Severe ulcerative colitis
• Reflux oesophagitis
• Narrow-angle glaucoma
• Thyrotoxicosis
• Prostatic hypertrophy

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No absolute contraindication to atropine in advanced cardiovascular life support (ACLS) or severe bradycardia

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Cautions

• Pregnancy
• Breastfeeding
• Renal impairment
• Hepatic impairment
• Elderly
• Children
• Down's syndrome
• Pre-existing diarrhoea
• Urinary retention
• Pre-existing fever
• Heart transplant patients
• Chronic obstructive pulmonary disease
• Patients whose condition may be aggravated by use of antimuscarinics
  - Reflux oesophagitis
• Toxic pyrexial children
• High ambient temperatures
• Conditions characterised by tachycardia such as thyrotoxicosis, cardiac insufficiency or failure and in cardiac surgery
• Presence of acute myocardial ischaemia or infarction
• May impair ability to drive and operate machinery

Forms avail. in SA and covered in this monograph: inj

In anaesthesia, to reduce the risk of vagal inhibition of the heart and to reduce salivary and bronchial secretions

• IV: 0.3-0.6mg, immediately before anaesthesia
• IM/SC: 0.3-0.6mg, 60min. before anaesthesia

Treatment of cholinergic crisis of myasthenia gravis 

• IV: 0.4-2mg, increase according to patient's response

In combination with neostigmine used to reverse the effects of non-depolarising muscle relaxants 

• IV: 0.6-1.2mg, given as a slow injection

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Atropine should be administered before neostigmine

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Cardiopulmonary Resuscitation

0.6mg/ml

• IV: 0.2-0.5mg, repeat if necessary

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Persistent bradycardia should be controlled by the insertion of a pacemaker as soon as possible

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1mg/ml

• IV: 3mg, as a single dose

Arrhythmias
- Bradycardia, particularly if complicated by hypertension

1mg/ml

• IV: Initial: 300μg, increasing to 1mg if necessary

Treatment of poisoning by certain cholinesterase inhibitors

• IV/SC/IM: Initial: 1.2-2mg, increase according to patient's response; Repeat every 5-10min. until signs and symptoms appear

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Admin. is by SC/IM/IV unless recommended as IV admin. only 

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Dosing varies considerably depending on the severity of poisoning

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For carbamate poisoning, the overall amount of atropine used is usually less than with organophosphate insecticide or nerve agent poisoning

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Patients who have been severely poisoned may exhibit significant tolerance to atropine therefore ≥2 times the recommended doses may be required

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IV slow injection may result in paradoxical bradycardia

Paed. forms avail. in SA and covered in this monograph: inj

In anaesthesia, to reduce the risk of vagal inhibition of the heart and to reduce salivary and bronchial secretions

Premature Infants

• IM/SC: 65μg, 30-60min. before induction of anaesthesia

Full-term Infants

• IM/SC: 100μg, 30-60min. before induction of anaesthesia

Between 6 months - 1 year

• IM/SC: 200μg, 30-60min. before induction of anaesthesia

Older than 1 year

• IM/SC: 10-20μg/kg, 30-60min. before induction of anaesthesia

Alternate dosing (by weight)

• SC: Give 30min. before induction of anaesthesia
• IM: Give 30-60min. before induction of anaesthesia

Weight	Dose
Premature infants	65μg
≤3kg	100μg
7-9kg	200μg
12-16kg	300μg
20-27kg	400μg
32kg	500μg
41kg	600μg

Antidote to cholinesterase inhibitors

1mg/ml

• IV/IM: 50μg, repeat every 5-10min. until signs of atropinisation appear

Antidote to organophosphate pesticides and in mushroom poisoning

1mg/ml

• IV/IM: 50μg, repeat every 10-30min. until muscarinic signs and symptoms subside

Cardiopulmonary Resuscitation

1mg/ml

• IV: 20μg, as a single dose

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Dosing varies considerably depending on the severity of poisoning

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For carbamate poisoning, the overall amount of atropine used is usually less than with organophosphate insecticide or nerve agent poisoning

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IV slow injection may result in paradoxical bradycardia

Pregnancy

• Caution; no evidence of risk in studies
• Atropine sulfate crosses the placenta. Studies in humans have not been done and only limited information is available from animal studies. Animal studies are insufficient with respect to reproductive toxicity
• Intravenous administration of atropine during pregnancy or at term may cause tachycardia in foetus. Atropine should only be administered to pregnant women if the benefits outweigh the risks to the foetus

Breastfeeding 

• Caution
• Trace amounts of atropine appear in the breast milk and may cause antimuscarinic effects in the infant; lactation may be inhibited

Fertility

• There are no adequate preclinical fertility data with atropine, and no epidemiological data

Renal Impairment

• Caution; no information available

Hepatic Impairment

• Caution; no information available

Elderly

• Caution; no dose adjustment recommended

Porphyria Information

• Probably not porphyrinogenic (PNP)

Drugs in Sport

• Permitted - No warnings

Central Nervous System Disorders

• Confusion (especially in the elderly)
• Hallucinations
• Drowsiness
• Restlessness
• Delirium
• Dizziness
• Excitement

Cardiovascular Disorders

• Paradoxical atrioventricular block, especially after heart transplantation
• Transient bradycardia followed by tachycardia, palpitations, arrhythmias
• Exacerbation of myocardial ischaemia or myocardial infarction
• Flushing

Respiratory Disorders

• Reduced bronchial secretion

Gastrointestinal Disorders

• Dry mouth
• Dysphagia
• Constipation
• Nausea and vomiting
• Inhibition of gastric secretion
• Retrosternal pain due to gastric reflux

Genitourinary Disorders

• Difficulty with micturition
• Urinary retention

Endocrine and Metabolic Disorders

• Thirst

Skin and Subcutaneous Tissue Disorders

• Dry skin
• Urticaria
• Rash
• Skin exfoliation

Immune, Blood and Lymphatic System Disorders

• Anaphylaxis
• Fever

Sensory Disorders

• Dilatation of the pupils with loss of accommodation
• Blurred vision
• Photophobia
• Raised intraocular pressure

• Antihistamines
• Tricyclic antidepressants
• Monoamine oxidase (MAO) inhibitors
• Disopyramide
• Domperidone
• Phenothiazines
• Amantadine
• Butyrophenones
• Antispasmodics
• Anti-parkinsonian agents
• Quinidine
• Beta-blockers
• Ketoconazole
• Chlorpromazine
• Olanzapine
• Clozapine
• Mexiletine
• Sublingual agents, such as nitrates
• Gastrointestinal prokinetic agents
• Metoclopramide
• Neostigmine

• Vital signs
• Heart rate
• Blood pressure
• Pulse
• Mental status

Specific cases may require

• ECG

Atropine is an antimuscarinic agent which competitively antagonizes acetylcholine at postganglionic nerve endings, thus affecting receptors of the exocrine glands, smooth muscle, cardiac muscle and the central nervous system. Peripheral effects include tachycardia, decreased production of saliva, sweat, bronchial, nasal, lachrymal and gastric secretions, decreased intestinal motility and inhibition of micturition. Atropine increases sinus rate and sinoatrial and AV conduction. Usually, heart rate is increased but there may be initial bradycardia. Atropine inhibits secretions throughout the respiratory tract and relaxes bronchial smooth muscle producing bronchodilatation.

Injection (per ml) 0.5mg

• Atropine Sulphate Fresenius (Fresenius Kabi)
• Pharma-Q Atropine (Pharma-Q)
• Sabax Atropine (Adcock Ingram) originator

Injection (per ml) 0.6mg

• Atropine Sulphate Fresenius (Fresenius Kabi)

Injection (per ml) 1mg

• Atropine Sulphate Fresenius (Fresenius Kabi)
• Pharma-Q Atropine (Pharma-Q)
• Sabax Atropine (Adcock Ingram) originator

Also available in the following form: Eye drop.