Atropine dose , mechanism of action and side effects...phrmacyteach.com

Drug profile of Atropine

  

Atropine dose , mechanism of action and side effects...phrmacyteach.com 

 

Introduction 

Atropine is a naturally occurring anticholinergic drug that blocks the action of acetylcholine, a neurotransmitter responsible for transmitting nerve impulses. It has been used extensively in the medical field due to its ability to affect various systems of the body.

Generic Name:-

·         Atropine (sulfate )

Structure of atropine:-

·         Chemically, atropine (sulfate) is designated as 1 H,5 H-Tropan-3 –ol (±) –tropate. Its empirical formula is C₁₇H₂₃NO₃ and its structural formula is:

 

Brand Names with Manufacturer:-

1)      Anespin (Oriental Chemical Works) 

2)      Atrospan (Fischer) 

3)      Bellapan (Farmapol) 

4)       Antol (Ying Yuan) 

5)      AtroPen (Meridian) 

6)       Atropt (Sigma) 

7)      Dysurgal (MaxMedic) 

 

Dosage Forms of atropine:-

Available is available in numerous dosage forms including

·       oral tablet,

·       solution for injection,

·       ophthalmic solution,

·       and ophthalmic ointment.

 

Strength:-

 

intramuscular device

·       0.25mg/0.3mL

·       0.5mg/0.7mL

·       1mg/0.7mL

·       2mg/0.7mL

 

 

injectable solution

·       0.05mg/mL

·       0.1mg/mL

·       0.4mg/mL

·       0.8mg/mL

·       1mg/mL

 

 

Dose of atropine for adult and pediatric:-

·        Dosing atropine in adults to greater than 0.5 mg and slow IV.

·         The dose for atropine is 0.02 mg/kg; therefore, the lowest dose recommendation affects infants with a body weight of <5 kg.

 

Pharmacodynamics of atropine:-

Drug class	Anti-muscarinic (anticholinergic drug)
Mechanism Of Action	Atropine competitively antagonist the effects of acetylcholine, atropine also inhibits excess acetylcholine due to organophosphorus poisoning, apart from this atropine also block the action of acetylcholine at; ·       muscarinic cholinergic receptors on smooth muscle, ·       cardiac muscle, ·       secretory gland cells, ·       and in peripheral autonomic ganglia and the central nervous system.
site of action of atropine	Site of action of Atropine is the same as acetylcholine.  Atropine competes for the muscarinic acetylcholine receptor types M1, M2, M3, M4, and M5.
Therapeutic Action of Atropine	Atropine block gland secretions in the mouth and respiratory passages, cause mydriasis, cause bronchodilation, and urine retention in elder males, decrease acid secretions in the stomach, and cause tachycardia.
Secondary pharmacodynamics responses	In addition to therapeutical activity in some individuals, atropine can cause complete heart block, and atropine can accelerate the idioventricular rate.   postural hypotension may be developed by atropine. It is due to Systemic doses of atropine which marginally elevate systolic and lower diastolic pressures.

 

 

                 

Pharmacokinetics of atropine:-

o   Atropine is well absorbed from g.i.t and after intramuscular administration.

o    Distribution occurs throughout the body tissues and fluids.

o   Much of the drug is metabolized in the liver by enzymatic hydrolysis,  noratropine, tropine, and tropic acid are major metabolites of atropine. Organophosphate pesticides inhibit the metabolism of atropine.

o   Atropine excreted From 13 to 50% in unchanged form in the urine.it is also reported that  Atropine is excreted in human milk.

o   Atropine can enter the fetal circulation by crossing the placental barrier.

 

Pharmacokinetic of atropine  in table form;

Bioavailability	25%
Metabolism	≥ 50%  hydrolyzed to tropine and tropic acid
Elimination half-life	2 hours
Duration of action	30 to 60 mints
Excretion	15–50% excreted unchanged in the urine

 

What Are the Uses of Atropine?

 

Let’s talk about atropine uses. This drug has a long and complicated history, but its main use is to treat certain types of poisoning.

 

Atropine was first used as a poison antidote in the 1800s, and it’s still used for that purpose today. It’s also used to treat heart problems, stomach cramps, and other issues.

 

One of the atropine’s most common uses is to stop someone from vomiting. It’s also used to dilate the pupil, which can help with eye problems. And finally, atropine can be used as a muscle relaxant.

 

Indications ( pharmacotherapeutic application) of atropine:-

Atropine (sulfate) is primarily indicated in conditions like anesthesia, arrhythmias after myocardial infarction, as an antidote to organophosphorus (insecticides)p poisoning, asthma, cardiopulmonary resuscitation, choroiditis, control of muscarinic side effects of neostigmine, diarrhea, drying secretions, dysenteries, intra-operative, bradycardia, iridocyclitis, irritable colon syndrome, myocardial infarction, peptic ulcer, poisoning, pyloric disease, tetanus.

Here we will see the action of atropine on different systems of the body.

1 . Effect of atropine on CNS:-

As we see atropine is an anticholinergic drug which means atropine decreases parasympathetic activities and increases sympathetic activities. so the action of atropine on CNS is a stimulant. A low dose of atropine normally does not produce this action because atropine is very poor brain permeability.

Atropine suppressed tremor and rigidity of Parkinsonism by blocking over activity of cholinergic in the basal ganglia.

High doses of atropine can cause over-excitation, hallucinations, restlessness, and delirium that is followed by respiratory depression and coma.

   2. Effect of atropine on CVS:-

The most prominent effect of atropine on the heart is tachycardia (increase heart rate). It is due to the blockage action of atropine on the SA node of the heart.

At low dose; atropine cause bradycardia it is due to the blocking of the M1 receptor of pre-synaptic neurons of the heart.

At high dose; Atropine cause tachycardia it is due to the blocking of M2 receptors of the heart.

   3. Effect of Atropine on the eye:-

 Atropine sulfate drops are used to develop mydriasis( dilation of the pupil ) before eye examinations.

Atropine can cause blurring of near vision, and increase intraocular tension. Therefore Atropine is contraindicated in glaucoma.

    4. Effect of Atropine on smooth muscle:- 

The relaxation effect comes in smooth muscle by atropine due to M3 receptor blockage.

 

Drug-Drug interaction of atropine:-

 

What Are the Drug-Drug Interactions of Atropine?

Let’s talk about the drug-drug interactions of atropine. This is an important topic, because atropine can interact with other medications you might be taking.

 

Some of the most common drug-drug interactions are with medications that are used to treat psychiatric conditions, like haloperidol or clozapine. Atropine can also interact with antihistamines and drugs that are used to treat Parkinson’s disease. So if you’re taking any of these medications, be sure to tell your doctor before you start taking atropine.

 

Your doctor will need to know all of the medications you’re taking because atropine can also interact with over-the-counter and herbal products. So be sure to tell your doctor about every medication, supplement, and vitamin you’re taking.

Drugs	Interactions
1,2-benzodiazepine	1,2-Benzodiazepine may increase the central nervous system depressant (CNS depressant) activities of Atropine.
Acebutolol	Atropine may increase the arrhythmogenic activities of Acebutolol.
Aceclofenac	The risk or severity of hypertension can be increased when Atropine is combined with Aceclofenac
Acemetacin	The risk or severity of hypertension can be increased when Atropine is combined with Acemetacin.
Acetazolamide	Acetazolamide may increase the central nervous system depressant (CNS depressant) activities of Atropine.
Acetyldigitoxin	Acetyldigitoxin may increase the arrhythmogenic activities of Atropine.

 

Drug-food interaction

Some food interferes in absorption, such as green tea, black tea,  black walnut, red raspberry, oak, and witch hazel, when atropine is taken by mouth.

 

Drug-disease interaction

Atropine can increase the risk of developing acute angle glaucoma, pyloric obstruction, and other related diseased.

 

Side effects of atropine:-

Adverse reactions to atropine include;

·       ventricular fibrillation

·       supraventricular or ventricular tachycardia

·       Dizziness

·       Nausea

·       blurred vision

·       loss of balance

·       dilated pupils

·       Photophobia

·       dry mouth and potentially extreme confusion

·       deliriant hallucinations

·       and excitation especially among the elderly.

 

These latter effects are because atropine is able to cross the blood–brain barrier. Because of the hallucinogenic properties, some have used the drug recreationally, though this is potentially dangerous and often unpleasant

 

What Are the Contraindications of Atropine?

 

When it comes to atropine, there are a few contraindications you should be aware of. First and foremost, atropine should not be given to people who are pregnant or breastfeeding. It can also have harmful effects on young children, so it’s important to keep this in mind if you have kids in your life.

 

Additionally, atropine should not be given to people who are allergic to it, and it should not be taken with other medications, such as tricyclic antidepressants or phenothiazine. If you’re taking any of these medications, be sure to speak with your doctor before taking atropine.

 

Toxicity of atropine:-

What Is the Toxicity of Atropine?

Atropine can cause blurred vision, dilated pupils, dry mouth, difficulty urinating, and constipation.

In high doses, it can also lead to hallucinations, tremors, confusion, delirium, and ataxia. And in extreme cases, atropine can be fatal.

Severe intoxication can cause death due to circulation collapse, as a result, leading to a decrease in blood pressure and respiratory failure.

So it’s important to always follow the dosage instructions carefully and to never take more atropine than prescribed. And if you experience any of these side effects, be sure to speak to your doctor right away.

 

Toxicity Management of Atropine:-

Ø Physostigmine or pilocarpine is used as an antidote for atropine poisoning.

Ø Supportive treatment should be performed such as  Providing artificial respiration for preventing respiratory depressants.

Ø In case of atropine-induced photophobia, the room should be darkened.in case of photophobia induced by atropine.

Ø A short-acting barbiturate or diazepam may be used to reduce marked excitement and convulsions.

 

Precaution for atropine:-

 

Do not drive after the use of this medication because this medication causes blurry vision due to pupil dilation.

 Avoided in patients with glaucoma,, thyrotoxicosis, pyloric stenosis, fever, and urinary tract obstruction.

 

 

Storage conditions:-

Atropine, epinephrine, and lidocaine can be stored at room temperatures of  28.9 C for up to 45 days and bearable temperature points of up to 51.7 C for 13.25 hours without undertaking degradation

 

 

Conclusion

Atropine is a versatile medication widely used in various medical fields. Its ability to dilate pupils, increase heart rate, and alleviate gastrointestinal spasms has made it invaluable in ophthalmology, cardiology, and gastroenterology. However, it is essential to be aware of the potential side effects and take necessary precautions when using atropine. Always consult with a healthcare professional for guidance and supervision.

  FAQs (Frequently Asked Questions)

Can atropine be used for pain relief?

Atropine is not typically used for pain relief. Its primary applications are in dilating pupils, increasing heart rate, and treating gastrointestinal disorders.

Can atropine be purchased over the counter?

No, atropine is a prescription medication and should only be used under the supervision of a healthcare professional.

Are there any alternatives to atropine for dilating pupils?

Yes, there are alternative medications and techniques for dilating pupils, such as phenylephrine eye drops or specialized contact lenses. Your eye care provider can determine the most suitable option for your specific needs.

Can atropine be used during pregnancy?

The use of atropine during pregnancy should be carefully considered, weighing the potential benefits against possible risks. It is essential to consult with a healthcare provider before using atropine or any other medication during pregnancy.

 Are there any long-term side effects of atropine?

Prolonged use of atropine may lead to tolerance, where higher doses are needed to achieve the same effect. Additionally, chronic use can result in dry eyes and an increased risk of developing narrow-angle glaucoma. Regular monitoring and appropriate dosage adjustments are necessary for long-term atropine use.