Details About Overdose or Poisoning Generic Salt :: Atropine And Glycopyrrolate
Atropine and Glycopyrrolate
Drug Pharmacology ::
I. Pharmacology. Atropineand glycopyrrolate are parasympatholytic agents that competitivelyblock the action of acetylcholine at muscarinic receptors. Atropine isa naturally occurring tertiary amine that crosses the blood-brainbarrier and shares significant structural and functional similaritywith scopolamine, homatropine, and ipratropium. Glycopyrrolate is asynthetic quaternary amine that crosses the blood-brain barrier poorlyand is less likely than atropine to cause altered mental status ortachycardia. Desired therapeutic effects for treating poisoning includedecreased secretions from salivary and other glands, decreasedbronchorrhea and wheezing, decreased intestinal secretion andperistalsis, increased heart rate, and enhanced atrioventricularconduction. The elimination half-life of atropine is 2–4 hours (longerin children), with approximately 50% excreted unchanged in urine.Glycopyrrolate is excreted unchanged primarily in the bile and urine.
Drug Indications ::
Correctionof bronchorrhea and excessive oral and GI tract secretions associatedwith organophosphate and carbamate insecticide intoxication.Glycopyrrolate may be especially useful in managing peripheralcholinergic symptoms in cholinesterase inhibitor poisoning. Althoughglycopyrrolate will not reverse CNS toxicity associated withcholinesterase inhibitor poisoning, it also will not cause the CNS sideeffects seen with large doses of atropine, which are difficult todistinguish from the toxic effects of cholinesterase inhibitors.
Accelerationof the rate of sinus node firing and AV nodal conduction velocity inthe presence of drug-induced AV conduction impairment (eg, caused bydigitalis, beta blockers, calcium antagonists, organophosphorus orcarbamate insecticides, or physostigmine).
Reversalof central (by atropine) and peripheral (by atropine andglycopyrrolate) muscarinic symptoms in patients with intoxication by Clitocybe or Inocybe mushroom species.
Whenneostigmine or pyridostigmine is used to reverse nondepolarizingneuromuscular blockade, glycopyrrolate is the preferred agent to blockunwanted muscarinic effects (neuromuscular blockers, see NeuromuscularBlockers).
Drug Contra-Indications ::
All these contraindications are relative, and in some clinical situations benefit exceeds possible harm.
Patientswith hypertension, tachyarrhythmias, thyrotoxicosis, congestive heartfailure, coronary artery disease, valvular heart disease, and otherillnesses who might not tolerate a rapid heart rate. Patients withsevere cholinesterase inhibitor poisoning are often tachycardic.Atropine should not be withheld and may lower the heart rate (byimproving oxygenation). Glycopyrrolate may also be helpful (due to itslessened propensity to cause a tachycardia).
Angle-closureglaucoma in which papillary dilation may increase intraocular pressure.(May be used safely if the patient is being treated with a miotic.)
Partial or complete obstructive uropathy.
E. Obstructive diseases of the GI tract, severe ulcerative colitis, bacterial infections of the GI tract.
Drug Adverse Effects ::
IV. Adverse effects
Adverseeffects include dry mouth, blurred vision, cycloplegia, mydriasis,palpitations, tachycardia, aggravation of angina, congestive heartfailure (CHF), and constipation. Urinary retention is common, and aFoley catheter may be needed. Duration of effects may be prolonged(several hours). Additionally, CNS anticholinergic toxicity (delirium)may occur with the large doses of atropine needed to treatcholinesterase inhibitor poisoning.
Atropinedoses of less than 0.5 mg (in adults) and those administered by veryslow intravenous push may result in paradoxic slowing of heart rate.
Use in pregnancy. Atropineis FDA category C (indeterminate). It readily crosses the placenta.However, this does not preclude its acute, short-term use for aseriously symptomatic patient (see Table III–1). Glycopyrrolate is FDAcategory B and crosses the placenta poorly.
Drug Lab Interactions ::
Drug or laboratory interactions
Atropinizationmay occur more rapidly if atropine and pralidoxime are givenconcurrently to patients with organophosphate or carbamate insecticidepoisoning.
Atropine and glycopyrrolate have an additive effect with other antimuscarinic and antihistaminic compounds.
Slowing of GI motility may delay absorption of orally ingested materials.
Drug Dose Management ::
Dosage and method of administration
Cholinesterase inhibitor poisoning (eg, organophosphate or carbamate insecticides, “nerve agents”).
1. Atropine. Foradults, begin with 0.5–2 mg IV; for children, give 0.02 mg/kg IV. (Thedrug may also be given via the intratracheal route; dilute the dose innormal saline to a total volume of 1–2 mL.) Double the dose every 5minutes until satisfactory atropinization is achieved. (Decreasedsecretions and wheezing, increased heart rate.) Severely poisonedpatients may require very large doses (eg, up to 100 mg over a fewhours) of atropine determined by chemical titration and control ofmuscarinic symptoms. In mass-casualty situations, atropine can be givenIM. It may also be administered by ophthalmic and inhalation routes forreversal of topical effects from gas or mist exposures.
2. Glycopyrrolate. Initial IV dose for adults is 1–2 mg (children: 0.025 mg/kg).
3. Other agents. Ifmass-casualty situation depletes the local supply of atropine andglycopyrrolate, other muscarinic receptor antagonist agents such asscopolamine (tertiary) and ipratropium (quaternary) may be considered.
4. Therapeutic endpoints. Thegoal of therapy is the drying of bronchial secretions (this endpointmay be reached prematurely if the patient is dehydrated) and reversalof wheezing and significant bradycardia. Recrudescence of symptoms mayoccur, and in severe poisonings several grams of atropine may berequired and may be administered by constant IV infusion or with largerbolus doses and/or more frequent intervals (eg, 3–5 minutes).
Drug-induced bradycardia. Atropineis usually the drug of choice in this circumstance. For adults, give0.5–1 mg IV; for children, give 0.02 mg/kg IV up to a maximum of 0.5 mgand 1 mg in adolescents. Repeat as needed. Note that 3 mg is a fullyvagolytic dose in adults. If a response is not achieved by 3 mg, thepatient is unlikely to benefit from further treatment unlessbradycardia is caused by excessive cholinergic effects (eg, carbamateor organophosphate overdose).
Drug Chemical Formulations ::
Parenteral. Atropinesulfate injection, 0.05-, 0.1-, 0.3-, 0.4-, 0.5-, 0.6-, 0.8-, 1-, and1.2-mg/mL solutions. (Atropine has been stockpiled by the StrategicNational Stockpile (SNS) program as 20-mL vials of the 0.4 mg/mLsolution and combined (2 mg per dose) with pralidoxime (600 mg perdose) in the Mark 1 autoinjector kits.) Use preservative-freeformulations when massive doses are required. Glycopyrrolate injection(Robinul, others), 0.2 mg/mL in 1-, 2-, 5-, and 20-mL vials (some with0.9% benzyl alcohol).
The suggested minimum stocking levelto treat a 70-kg adult for the first 24 hours is 1 g atropine and 20 mgglycopyrrolate (higher amounts may be needed if this is the soleantimuscarinic agent).