adrenergic and anticholinergic, Slides of Pharmacology

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RES

Anticholinergic

(Parasympatholytic)

Bronchodilators

Chapter 7

Objectives (1 of 2)

▪ Define terms that pertain to anticholinergic

bronchodilators

▪ Differentiate between parasympathomimetic/

parasympatholytic, cholinergic/anticholinergic,

and muscarinic and antimuscarinic

▪ Explain the difference between tertiary and

quaternary ammonium compounds.

▪ List all available anticholinergic agents used in

respiratory therapy

Objectives (2 of 2)

▪ Discuss the indication for anticholinergic

agents

▪ Explain the mode of action for anticholinergic

agents (antimuscarinic)

▪ Identify the route of administration available

for anticholinergic agents

▪ Discuss adverse effects for anticholinergic

agents

▪ Discuss the clinical application for

anticholinergic agents

▪ Memorize any drug highlighted in turquoise

Terminology and method of action review Anticholinergics - what do they do? Which receptors do they target? Are they agonists or antagonists? Are they long-acting or short acting?

Muscarinic Receptor Subtypes

▪ M 1 ▪ Parasympathetic ganglia ▪ Facilitate neurotransmission and bronchoconstriction ▪ Cause secretion and rhinitis in the nose ▪ M 2 ▪ Inhibit continued use of acetylcholine ▪ May enhance acetylcholine release, counteracting bronchodilation (tiotropium is selective for M 1 and M 3 ) causing bronchoconstriction ▪ M 3 ▪ Smooth airway muscle and submucosal glands ▪ Cause bronchoconstriction ▪ Cause secretion production and rhinitis in the nose

Pharmacological Effects

Background on anticholinergic (antimuscarinic) agents:

▪ Previous anticholinergics were tertiary ammonium

compounds. They were easily absorbed across mucosal membranes causing many systemic side effects.

▪ Respiratory tract: inhibits and reduces mucociliary clearance

▪ Central nervous system-crosses blood brain barrier: restlessness, irritability drowsiness or alternately, mild excitement ▪ Eyes-pupil dilation, blurred vision ▪ Cardiac: decrease or increase HR depending upon dose ▪ Gastrointestinal: dry mouth, slowing GI motility ▪ Genitourinary: urinary retention ▪ We now give quaternary ammonium compounds that do not generally cross lipid membranes easily, resulting in less systemic and more local/topical effects. ▪ Respiratory tract – bronchodilation ▪ Gastrointestinal – dry mouth, cough

Anticholinergic/antimuscarinic

Subclasses

If it is less than 12 hours (Ipratropium Bromide) it is a Short-Acting Muscarinic Antagonist or SAMA All of the other anticholinergics are long-acting agents (12 or more hours). So, they would be called…. wait for it…

Clinical Indications for Use ▪ Indication for anticholinergic bronchodilator

▪ Bronchospasm, acute treatment

▪ COPD maintenance

▪ Asthma ▪ Nocturnal asthma – those who wake up wheezing ▪ Asthmatics being treated for another condition with β-blockers ▪ When adrenergic bronchodilators are contraindicated

▪ Cardiac conditions or tachycardia

▪ Because these target parasympathetic receptors- there are minimal cardiac side effects

Bring out your drug cards or use this

template

As we go through this PPT, I will pause occasionally and have you and your neighbors fill in the different fields. By the end of this PPT, I want you to have a completed card on Ipratropium Bromide and Albuterol

▪ Indication for combined anticholinergic and

β-agonist bronchodilators

▪ COPD maintenance with patients who continue to have evidence of airflow obstruction/bronchospasm ▪ Also used in cases of severe asthma not responsive to β-agonist therapy

Clinical Indications for Use – Adjunctive therapy

Vagally Mediated (Parasympathetic) Reflex Bronchoconstriction Anticholinergics can be especially helpful with Sensory C fiber bronchoconstriction

▪ Sensory C-fibers respond to irritant aerosols, cold air,

high airflow rates, smoke, fumes, histamine release

▪ When activated, they send *afferent impulse to CNS

which sends an efferent cholinergic impulse to M

receptors resulting in constriction of airway smooth

muscle mucus and cough

▪ Can be blocked by competitive inhibitors of

acetylcholine (Anticholinergics)

*What does this mean again * Going towards the CNS?

Contraindications for Use

Anticholinergic bronchodilators are generally safe so there are no absolute (never give) contraindications. Relative(use your discretion)contraindications:

▪ History of hypersensitivity to any of the ingredients

▪ When taking a LAMA, avoid administering other

anticholinergic agents as they have additive

effects.

▪ Regular long-term use of short and long-acting

agents should be regularly assessed

▪ Use of anticholinergic agents in patients who have

vision problems, such as glaucoma, should be

closely monitored

Drug Interactions

Monotherapy (just anticholinergic):

▪ May interact additively with concomitantly used anticholinergic medications. Avoid administration with other anticholinergic-containing drugs.

Combination medication with an adrenergic medication:

Add these interactions as well

▪ Use of other adrenergic by any route may potentiate the effect. Use with caution. ▪ Monoamine oxidase inhibitors and tricyclic antidepressants: Use with extreme caution. May potentiate effect of adrenergics on cardiovascular system. ▪ Beta-blockers: Use with caution and only when medically necessary. ▪ Sympathomimetics should be used with caution in patients with cardiovascular disorders, tachycardia, coronary insufficiency, cardiac arrhythmias, and hypertension ▪ As with any adrenergic medication, stop treatment if HR increases by 20%