22. Chap 15.1, 15.2 Antihistamines and decongestants

Define an antitussive medication

A drug that reduces coughing

What are some ways that respiratory medications can be delivered? (2 ways)

Oral or injections

Inhalation

How do oral/injected meds work on the respiratory system? Why are they not favorable?

Reach lungs via pulmonary circulation, useful if airway is obstructed

Not selective for respiratory tract, so act on other tissues

Why are inhaled respiratory medications preferable? (2 reasons)

Better at delivering drug directly to lungs

Fewer systemic side effects, smaller doses

What are the main delivery options for inhaled respiratory medications? (3)

Metered dose inhalers (MDIs)

Nebulizers

Dry powder inhalers

How do MDIs work?

Push down on button and inhale the drug at the same time (asthma inhalers)

How do nebulizers work? Why are they more effective than MDIs?

Medication is aerosolized into small particles, inhale for 15-20 minutes

Smaller particles are diffused easier

Why are dry powder inhalers easier to use than MDIs?

They reduce the need for the timing effect of MDIs

What are some types of drugs that control respiratory tract irritation and secretion? (4)

Antitussives

Antihistamines

Decongestants

Mucolytics and expectorants

Most commonly, antitussives are this type of medication. Why do they work to reduce coughing?

Most commonly opioids

Suppress cough reflex at brainstem

What are some examples of opioid antitussives? (3 drug names)

Codeine

Dextromethorphane

Hydrocodone

Are antitussive opioids often combined with other drugs?

Yes, often combined with decongestants, etc in OTC products

How does Benzonatate work to reduce coughing?

Has an anesthetic effect on vagal nerve endings in airway, reduces effects of irritation that start the cough reflex

What are the primary side effects of antitussive medications? (2)

Sedation and dizziness

GI upset

What are the rehab concerns for using antitussives? (3)

Overuse and dependence

May limit a productive cough

Effectiveness unknown

Does the American College of Chest Physicians recommend that cough medications be used in children to prevent or manage cough?

No, they state that they offer no symptomatic relief and may experience dangerous side effects

How do antihistamines stop coughing caused by seasonal allergies and colds?

Block the H1 receptor in the lungs, decreasing the effects of histamine on the upper respiratory tract

What is one of the main problems with using antihistamine drugs? How is this being solved?

Often cause dizziness and sedation

New drugs being developed that cause less dizziness and sedation

Name 2 non-sedative antihistamine drugs and 2 sedative antihistamines

Non-sedative: Zyrtec, Allegra

Sedative: Dramamine, Benadryl

What are the primary side effects caused by antihistamines if the drug crosses the blood brain barrier? (meaning it's not specific to the respiratory system) (2 effects)

Sedation and fatigue

Incoordination and blurred vision

What are the rehab concerns for using antihistamines? (2)

Sedative effects

Dry out respiratory tract and limit productive coughs

How do alpha-1 receptor agonist decongestants work on the respiratory tract to decrease a runny nose?

They vasoconstrict nasal mucosa, causing a decreased release of mucous

Why is it important to administer alpha-1 receptor agonist decongestants locally whenever possible (instead of systemically)?

Because the drug mimics epi and norepi, and can cause serious side effects in the rest of the body like cardiac palpitations and increased BP

What are the primary side effects of decongestants? (2)

Headache, nausea and nervousness

CV stimulation

Define mucolytic drugs

Those that break up mucous, decreasing it's viscosity and making it easier to raise and expel secretions

Define expectorant drugs

Those that increase the production of a thinner, more liquid phlegm, enhancing the effects of mucolytics

How does Mucomyst work as a mucolytic? What other solution mimics this drug? What else can this drug be used for?

Breaks up disulfide bonds in mucous, decreasing viscosity

Same effect from breathing warm saline mist

Antidote for acetaminophen poisoning

How does Pumozyme work as a mucolytic? What condition is it helpful for?

DNA-ase that breaks up DNA "glue" that holds mucous together

Helpful in people with cystic fibrosis

How does Guaifenesin work as an expectorant? What drug is it found in?

Increases fluid content of phlegm

Found in Mucinex

What are some of the primary side effects of mucolytics and expectorants? (2)

Usually well tolerated

May have nausea, vomiting, mouth irritation

When are mucolytics and expectorants useful during PT?

During postural drainage, vibration and percussion

Are there any major concerns for using mucolytics and expectorants during rehab?

No