drugs that affect the respiratory system

Drugs that Affect the

Respiratory System

P. AndrewsChemeketa Community College

Paramedic ProgramFall 07

When do we consider respiratory medications?

• Asthma– Decreases pulmonary function– May limit daily activity– Presents with

• SOB• Wheezing• Coughing

Or, perhaps……

• SOB, unknown etiology• Allergic reaction• Pneumonia• Congestive heart failure• Emphysema • Others…..?

Asthma, cont.

• Has numerous components!– Bronchoconstriction– Inflammation– Edema– Mucus hypersecretion– And others….

• Usually an allergic reaction

Categories of respiratory

meds

• Bronchodilators• Beta2 specific agonists

(short-acting)• Beta2 specific agonists

(long-acting)• Methylxanthines

• Anticholinergics• Glucocorticoids• Leukotriene

antagonists• Mast-cell membrane

stabilizer

Advantages of Nebulized Meds.

• Smaller doses

• Onset Rapid

• Targeted delivery

• Less side effects

Disadvantages of Inhaled Meds

• Variables in delivery

• Usage variables– User

– Caregiver

• Requires delivery to lungs– Not always adequate depth of respiration

Remember This?

• Absorption• Distribution• Metabolism• Elimination

Absorption and Distribution

• Absorption– Ionized drugs (Ipratropium)

• Absorb poorly• Won’t distribute well to body• Mostly local effect• Used for AEROSOL

– Non-Ionized drugs (Atropine)• Absorb well• Distribute well• Systemic Effect• Poor Aerosol Drug

Quick Review of Receptors

– Sympathetic• Adrenergic

– Epinephrine or Nor-epinephrine» Primary neurotransmitters

– Parasympathetic• Cholinergic

– Acetylcholine» Primary neurotransmitter

Muscarinic

• A drug that stimulates Acetylcholine at Parasympathetic nerve endings.

• When drugs refer to muscarinic or antimuscarinic action,– It ONLY acts on Parasympathetic sites!

Adrenergic Stimulation

• Alpha 1– Vasoconstriction– Increase Blood Pressure

• Beta 1– Increase Heart Rate– Increase Force of Heartbeat

• Beta 2– Bronchial Smooth Muscle Dilation

Adrenergic Bronchodilators

• Indication– Obstructive Airway Disease

• Asthma, Bronchitis, Emphysema

• Mode of Action– Adrenergic Receptors

• Alpha 1…vasoconstriction• Beta 1…Increase HR • Beta 2…Bronchodilate (Yeah!)

Adrenergic Bronchodilators

• Adverse Effects– Dizziness, – Nausea, – Tolerance, – Hypokalemia, – Tremors– H/A

Adrenergic Bronchodilators• Nonspecific agonists

– Epinephrine (rarely used)• Beta2 Specific agonists – Short acting

– Albuterol (Ventolin, Proventil)• 2.5 mg in 3 mL NS

– Metaproterenol (Alupent)– Terbutaline (Brethine)

Bronchodilators, cont.

• Inhaled Beta2 selective (long-acting)– Salmeterol (Serevent)

Anticholinergic Bronchodilators

• Indication– Bronchoconstriction– Mainly in COPD

• Mode of Action– Competes at Muscarinic receptors– Blocks Acetylcholine at smooth muscle– Reduces Mucus Production

Anticholinergic Bronchodilators• Adverse Effects

– Watch for Cholinergic side effects– More with nebulized form than MDI

• Examples– Atrovent (ipratropium)

• 0.5 mg in 2.5 mL NS– Combivent (mixed w/ Albuterol)

• 0.5 mg Atrovent & 2.5 mg Albuterol in 3 ml NS)– Atropine

• 0.5 – 1 mg in 2 – 3 mL of NS– Robinul

• Peak effects in 1 – 2 hrs

Mucus Controlling Agents

• Indication– Excessive , thick secretions

– As in COPD and TB

• Action– Lower viscosity of mucus

Mucus Controlling Agents

• Side effects– Irritation of Airway– Bronchospasm– Pharyngitis, voice change, laryngitis– Chest pain– Rash

• Considerations– Have suction ready – Anticipate cough

Mucus Controlling Agents

• Examples– Mucomyst (Acetylcysteine)

• COPD, TB• Acetaminophen OD

– Pulmozyme• Cystic Fibrosis

– Nebulized Saline• Simple yet effective!

Inhaled Corticosteroids

• Indications– Asthma– Anti-Inflammatory MAINTENANCE– Require Hours to Act! Preventative drug

• Mode of Action– Modifies RNA/DNA action in Cells– Complicated Stuff

Inhaled Corticosteroids

• Adverse Effect– Small incidence with nebulized

• Oral doses have high incidence

• Considerations– Not valuable in Acute Care– Watch for these in Pt Drug Lists

Corticosteroids

• Examples– Beclovent, Vanceril– Azmacort– Aerobid– Flovent– Pulmicort– Advair®

• fluticasone (steroid) and salmeterol (bronchodialator)

Glucocorticoids

• Indications– Prophylactic treatment of Asthma

– Hayfever

Glucocorticoids (cont)

• Mode of Action– Lowers release of Histamine in Mast Cells– Lowers release of Inflammatory Response

• Prevents Bronchospasm, airway inflammation– Acts in allergic and non-allergic asthma– Not a bronchodilator!

• Not for use in acute setting• Controllers, not relievers

Glucocorticoids (cont)

• Adverse Effects– Include

• H/A

• Nausea

• Diarrhea

Cromolyn sodium

• Similar to glucocorticoids

• Adverse Effects

– Only coughing or wheezing

Anti-inflammatory Agents, cont.

• Corticosteroids - Injected– Methylprednisolone (Solu-Medrol)

• Children; 0.25 mg/kg (max dose 125 mg IVP)• Adults; 125 mg IVP

– Dexamethasone (Decadron)

Nasal Decongestants

• Alpha1 agonist– Phenylephrine– Pseudoephedrine– Phenylpropanolamine

• Administered as mist or drops• Side Effects – rebound congestion (use

greater than 7 days)

Antihistamines• Blocks histamine receptors• Common 1st generation – cause sedation

– Chlor-Trimeton– Benadryl– Phenergan

• Common 2nd generation – does not cause sedation– Seldane– Claritin– Allegra

• Caution: thickens bronchial secretions – do not use in Asthma!

Cough Suppressants

• Antitussive meds – suppress cough stimulus in CNS– Codeine, hydrocodone

A couple of ‘odd’ ones

Epinephrine Racemic Epinephrine

(microNEFRIN)• Class

– Bronchodilator (adrenergic agonist)• Action

– Affects both beta1 and beta2 receptors sites. Bronchodilation, reduces subglottic edema

– Also increases pulse rate and strength– Also Alpha effects, vasoconstriction, Increased

BP

Epinephrine

• Indications– Croup, Epiglottitise

• Bronchospasm

• Absorption – Absorption occurs following inhalation

• Half-life– Unknown

Epinephrine

• Contraindications– Hypersensitivity

• Precautions– Watch for Rebound Worsening– Watch ECG for changes– Increases Myocardial O2 demand

• Side effects– Nervousness, restlessness, tremor, arrhythmias,

hypertension, tachycardia

Epinephrine

• Interactions– Beta blockers may negate effects

• Route and dosage– Inhalation

• One time Only• 1 mg Epinephrine, 1:1000 in 3 mL NS

• Considerations– Give ENROUTE– ONLY if patient in Extreme Distress

Epi, cont.

• May also consider Epi SQ – Patients who can’t cope with aerosol admin.– 0.3 – 0.5 mg SQ, then Neb treatment once

patient can move air• Or Infusion;

– 1 mg Epinephrine 1:1000 in 250 mL NS (concentration 4 mcg/mL) infuse at 1 mcg/min, titrating to effect

Magnesium Sulfate

• Not usually admin. in pre-hospital setting• Can be used to treat moderate to severe

asthma in patients who respond poorly to beta-agonists

• Don’t use in patients with heart blocks, myocardial damage, or hypertension

• 2 gm in 100 mL NS, given over 2 – 5 min.

Status Asthmaticus

•