CH. 31 Drug Therapy for Nasal Congestion and Cough

Common Cold:

viral infection of the upper respiratory tract and the most common respiratory tract infection

What is the most common virus that causes the common cold?

rhinovirus, however, many different viruses can cause a cold

How does the common cold spread?

rapid spread from infected people via nasal mucosa

• airborne: coughing, sneezing

• direct contact: can live on skin and hard surfaces for hours

How long does the common cold last?

lasts about 7 days

• incubation period is about 5 days

• most contagious period is about 3 days after start of symptoms

Why should antibiotics not be used to treat the common cold?

the common cold is caused by viruses, and antibiotics treat bacterial infections, not viral infections

Rhinosinusitis:

• combination of rhinitis and sinusitis

• both nose and sinus are inflamed

Sinusitis:

inflammation of the mucous membranes lining the paranasal sinuses

Rhinitis:

inflammation and congestion of the nasal mucosa

How does swelling affect the sinuses during rhinosinusitis?

swelling interferes with the ciliated mucous membranes, impairing mucus clearance and contributing to congestion

What happens to oxygen content in the sinuses during inflammation and blockage?

oxygen content in the sinuses decreases

Non-pharmacologic Treatment Options for Nasal Congestion and Other Respiratory Symptoms:

• adequate fluid intake

• humidifiers

• throat lozenges or hard candy

Drug Therapy Options for Nasal Congestion and Other Respiratory Symptoms:

• nasal decongestants

• antitussives

• expectorants

• mucolytics

Action of Nasal Decongestants:

temporarily relieves nasal obstruction and discharge by constricting arterioles and reducing blood flow to nasal mucosa

Pharmacokinetics of Nasal Decongestants:

• onset: 30 min

• peak: 1-2 hoAd ersurs

• half-life: 4-8 hours

• metabolized in liver to an active metabolite

• excreted by kidneys

Adverse Effects of Nasal Decongestants:

• hypotension, dysrhythmia

• impaired coordination

• dizziness, excitability, restlessness

• headache, insomnia, seizures

• dysuria, urinary retention

• thrombocytopenia

Contraindications of Nasal Decongestants:

• severe HTN or CAD

• narrow angle glaucoma

• tricyclic of MOAI antidepressants

• children under 2

• proceed with caution for

  • cardiac dysrhythmias

  • hyperthyroidism

  • DM

  • glaucoma

  • prostatic hypertrophy

  • renal impairment

  • pediatric population (<2 years)

Preventing Interactions While Using Nasal Decongestants:

• caffeine increases adverse effects

• coleus herb increases effect of drug

• herbs with tannin (tea, cloves, cumin, thyme) decreases effect

Administration of Nasal Decongestants:

• give with or without food

• do not crush extended release

What is the prototype nasal decongestant, and what is its brand name?

Pseudoephedrine (Sudafed)

What forms of pseudoephedrine tablets are available?

tablet (regular or extended-release)

Where is pseudoephedrine sold in the United States?

OTC sale restricted; behind the counter

How do most nasal decongestants work?

they cause vasoconstriction (narrowing of blood vessels), reducing swelling in the nasal passages and relieving congestion

What is another medication used as a nasal decongestant?

Phenylephrine, which is found in some decongestant products

Other Drugs in the Nasal Decongestant Class:

Oxymetazoline (Afrin)

nasal spray; acts directly on alpha receptors in nares to produce vasoconstriction

Vasocenstriction:

narrows blood vessels; reduces nasal swelling; relieves congestion

Action of Antitussives:

• suppresses non-purposeful coughing by depressing the cough center in the medulla oblongata or the cough receptors in the throat, trachea, or lungs

• local acting agents (throat lozenges and cough drops) supress cough by increasing the flow of saliva

Pharmacokinetics of Antitussives:

• duration of action: 3-8 hours

• peak: 15-30 minutes

• half-life: 1-4 hours

• first pass metabolism in liver to an active metabolite

• excreted by kidneys

Adverse Effects of Antitussives:

normal dosing

• nausea

• drowsiness

• rash

• difficultly breathing

doses exceeding recommendations:

• hallucinations and disassociation

narcotic antitussives pose a risk for respiratory depression, N/V, constipation, dizziness, drowsiness, pruritus, drug dependance, and death

Contraindications for Antitussives:

• hypersensitivity to drug

• caution in children

Preventing Interactions with Use of Antitussives:

• many medication interactions

• St. Johns wort and tryptophan (melatonin) increase the risk of serotonin syndrome

• alcohol increase CNS depression

Administration of Antitussives:

• administer undiluted

• avoid eating and drinking for 30 min after administration

What is the prototype antitussive, and what is its brand name?

Dextromethorphan (Delsym)

What type of cough is dextromethorphan best used to treat?

a nonproductive (dry) cough, which doesn’t produce mucus

What forms of dextromethorphan are available?

• liquid

• lozenges

• syrups

• sustained-action liquids

What important safety concern is associated with dextromethorphan?

it has abuse potential, especially when taken in excessive doses

Other Drugs in the Antitussives Class:

• Benzonatate (Tessalon Perles)

• peripheral acting non-narcotic antitussive; anesthetizes stretch receptors in respiratory passages

• advise patient to swallow capsule whole; no chewing or sucking

Prescription Antiitussives:

• Guaifenesin and hydrocodone (Hydro-Tussin HG) prototype

• contains an opioid; can depress CNS and related functions

• rarely prescribed due to opioid SE (side effect)

Actions of Expectorants:

liquefies respiratory secretions by irritating the gastric vagal receptors to stimulate respiratory tract fluid, increasing the volume but decreasing the viscosity of respiratory tract secretions

Pharmacokinetics of Expectorants:

• onset 4-6 hours

• duration: unknown

• half-life: 1 hour

• metabolized and excreted in urine

Adverse Effects of Expectorants:

• skin rash

• headache

• nausea

• vomiting

Contraindications of Expectorants:

hypersensitivity to drug

Administration of Expectorants:

• swallow sustained-release capsules/tablets whole

• increase water intake

• can take with or without food

Expectorants:

• prototype: Guaifenesin

• liquid, tablet, capsule, syrup

• Mucinex brand name is also used for many combination medications

Actions of Mucolytics:

liquefies mucous by disrupting the protein bonds of the mucous, therefore reducing the viscosity of mucous secretions

Pharmacokinetics of Mucolytics:

• onset: 1 min

• peak: 5-10 min

• duration of action: 2-3 hours

• metabolized in liver and excreted in urine

Adverse Effects of Mucolytics:

when inhaled:

• drowsiness

• N/V

Contraindications of Mucolytics:

hypersensitivity to drug

Administration of Mucolytics:

may give intermittent aerosol treatments via face mask, mouthpiece, or directly into tracheostomy

Mucolytics:

• prototype: Acetylcysteine (Acetadote, Parvolex)

• nebulizer, instillation

• can be used for acetaminophen overdosage (oral)

Herbal Remedies and Other Preparations Used as Cold Remedies:

Echinacea

• preparations differ in chemical composition depending on which part of the plant is used

• randomized trails have concluded echinacea products are no better than placebo in effectively treating the common cold

Herbal Remedies and Other Preparations Used as Cold Remedies:

Vitamin C

• used to reduce incidence and severity of common colds and influenza

• plays a role in the defense mechanisms of the respiratory system

• high doses can cause GI upset

Herbal Remedies and Other Preparations Used as Cold Remedies:

Zinc Sulfate

lozenges and syrup may reduce the duration and severity of cold symptoms