3. Atropine
Pharmacological actions/Mechanism of action
Atropine is a highly selective competitive blocker of muscarinic
receptor. It blocks all subtypes of muscarinic receptors.
Heart Causes tachycardia by blocking M2receptor
on SA node
Temperature Increases
Blood
pressure
No marked effect, vasodilation at high
doses
Smooth
muscles
Tone & contractility of smooth muscles are
reduced
Eye Mydriasis (Dilation of pupils), cyclopegia
(paralysis of accommodation)
4. Indication
• Analgesic spasmolytic in the treatment of gastro-intestinal spasms and
biliary or hepatic colic
• Antispasmodic in asthma
• Cough medicine (with codeine mixture)
• Treatment of tremor and rigidity in Parkinson's disease
• Mydriatic and during ophthalmic surgery
• Pre-anesthetic (to inhibit salivation and respiratory secretions and to
prevent the risk of vagal inhibition of the heart)
• Treatment of bradycardia and cardiac arrest in intensive care medicine
• Antidote to nerve agent poisoning (organophosphates poisoning)
Contraindication
• Patients with chronic respiratory disease because of it it acts on
parasympathetic nervous system in which inhibit salivary and mucus
secretion.
• It also contraindicated to patients with glaucoma, thyrotoxicosis, pyloric
stenosis (narrowing of opening of stomach), UTI obstruction and
hypersensitivity reactions.
5. Side Effects
Allergic reaction Dysphagia
Restlessness
Constipation Arrhythmias Confusion
Excitement Headache Dizziness
Blurred vision Respiratory depression
Photosensitivity reaction
Dose:
• For bradycardia- 500mcg IV push, may repeat every 3 to 5
minutes up to a total dose of 3 mg (maximum 0.04 mg/kg)
• For dilation of pupil- 1 drop of a 1% solution BID for 1 to 2 day,
0.5% solution for children.
• For pre-anaesthesia- 300 to 600 mcg S/c or I/M injection,
usually 30 to 60 minutes before anaesthesia.
8. Mydriatics Dilation Potency
Atropine 30-40 mins Potent
Homatropine 45-60 mins Less potent
Cyclopentolate 30-60 mins Potent &
rapidly acting
Tropicamide 20-40 mins Quickest &
briefest
9.
10. • Parkinson's disease (PD) is a neurodegenerative
disorder that affects predominately dopamine-
producing neurons in a specific area of the brain called
substantia nigra. Symptoms of Parkinsons’s disease
includes tremor, slowness of movements, limb rigidity,
etc.
• Anti-Parkinsonian drugs:
• Trihexphenidyl (Benzhexol) 2-10mg/day
• Procyclidine
• Biperiden
Levodopa + Carbidopa (dopa decarboxylase inhibitor)
12. Adverse Effects:
ANTI-CHOLINERGIC TOXIDROMES
• Symptoms: Agitated Delirium Signs Of Peripheral
Muscarinic Blockade: Blurred Vision, Coma, Decreased
Bowel Sounds, Delirium, Dry Skin, Fever, Flushing,
Hallucinations, Ileus, Memory Loss, Mydriasis (Dilated
Pupils), Myoclonus, Psychosis, Seizures, & Urinary
Retention
• Substances: The four "anti"s: Antihistamines,
Antipsychotics, Antidepressants & Antiparkinsonian
• Atropine, Benztropine, Datura, and Scopolamine.
“Blind as a bat, mad as a hatter, red as a beet, hot as Hares,
dry as a bone, the bowel and bladder lose their tone, and
the heart runs alone.”- Atropine Poisoning
Complications: Hypertension, Hyperthermia, Tachycardia
13.
14. Resuscitation
• ABCDE
Risk Assessment
• Agent(s), Dose(s), Time since
ingestion
• Clinical features and progress
• Patient factors and co-morbidities
Investigations
• Screening: ECG
• Specific: Drug levels,
Electrolytes, renal function,
ABG
Supportive Care
•Quiet, Well lit Room
•Intravenous Fluids
•Catheterization
•Diazepam for agitation
Decontamination
•Activated Charcoal
ANTI-CHOLINERGIC TOXIDROME MANAGEMENT
Antidotes
•Physostigmine 1-3mg i.v.