Ch 36 Antihistamines, Decongestants, Antitussives and Expectorants Flashcards
What are the primary anticholinergic actions of Histamines?
They affect the secretions of lacrimal, salivary and respiratory mucosal glands.
What are the functions of the bodily substance: Histamine?
- Nerve impulses in CNS
- Dilation of capillaries
- Contraction of smooth muscles
- Stimulation of gastric secretions
- ⬆ of HR
To regulate the actions of histamine, antihistamine drugs can be administered. What are their functions?
Antihistamines:
- Relax the extravascular smooth muscle of the respiratory tract
- Prevent or alleviate itching
- Prevent the release and actions of histamine
What are the indications of Antihistamines?
- Nasal allergies
- Seasonal or perennial allergic rhinitis (hay fever)
- Relief of some of the typical symptoms of the common cold
- Allergic reactions
- Motion sickness
- Parkinson’s disease (anticholinergic effects)
- Vertigo
- Sleep aid
What are the contraindications with the use of Antihistamines?
- Narrow angle glaucoma
- ❤ disease
- Kidney disease
- Hypertension
- Bronchial asthma
- COPD
- Peptic ulcer
- Seizure disorder
- Benign prostatic hyperplasia
- Pregnancy
What are the adverse effects of Antihistamines?
- Drowsiness
- Dry mouth
- Changes in vision
- Difficulty urinating
- Constipation, diarrhea
- ❤ dysrhythmias
What are some drug interactions w/ Antihistamines that the nurse should be aware of?
- Alcohol
- MAOIs
- CNS depressants
- Apple, grapefruit and orange juices
- St John’s wort
What are the 2 advantages and 1 disadvantage of oral decongestants?
Advantages:
- Oral route decongestants produce prolonged effects
- No rebound congestion
Disadvantage:
- Onset of action is more delayed and effect less potent
What are the 1 advantage and the 1 disadvantage of topical decongestants?
Advantage:
- Quick onset of action
Disadvantage:
- Rebound congestion
What are the advantages of inhaled decongestants?
Advantages:
- No rebound congestion
- Prevention of nasal congestion in pts w/ URI symptoms
What is the mechanism of action of the adrenergic nasal decongestants?
They shrink nasal mucous membranes and relieve nasal stuffiness by constricting the small arterioles of the upper respiratory tract (nasal sinuses).
What is the mechanism of action of steroid nasal decongestants?
They reduce the inflammatory response elicited by invading organisms (viruses + bacteria)
–> result = modulation of inflammatory symptoms to improve patient comfort and air exchange
What are the indications of nasal decongestants?
- Acute or chronic rhinitis
- Common cold
- Sinusitis
- Hay fever
- Other allergies
*Can also be used prior to surgery to facilitate nasal visualization
What are the contraindications of nasal decongestants?
- Narrow angle glaucoma
- Uncontrolled cardiovascular disease
- Hypertension
- Diabetes
- Hyperthyroidism
- Prostatitis
- Post CVA
What are the adverse effects of nasal decongestants?
1) Adrenergics
2) Steroids
1) Adrenergics:
- Nervousness
- Insomnia
- Palpitations
- Tremors (due to stimulation of the ❤, blood vessels and CNS)
2) Steroids:
- Local mucosal dryness and irritation
What drug interactions can be seen w/ decongestants?
- Systemic sympathomimetic drugs and sympathomimetic nasal decongestants are more likely to cause drug toxicity when given together.
- MAOIs may result in additive pressor effects
What are the 2 main category of Antitussives?
1) Opioid
2) Nonopioid
What are the only 2 opioids given as Antitussives?
- Codeine
- Semisynthetic derivative hydrocodone
What is the difference between opioid and nonopioid Antitussives?
Nonopioids are less effective and can be taken alone or in combo w/ other OTC cold and cough preparations.
How are the opioid and nonopioid Antitussives effective?
Opioids provide analgesia and have a drying effect –> ⬆ viscosity of respiratory secretions.
Nonopioids do the same w/out the analgesic effect
Result = ⬇ of symptoms such as runny nose and postnasal drip
What is the main indication of Antitussives?
To stop the cough reflex when the cough is nonproductive and/or harmful.
What are 2 examples of nonopioid Antitussives?
- Benzonatate (Tessalon Perles)
- Dectromethorphan (Vicks Formula, Robitussin-DM)
What are the adverse effects of Antitussives?
1) Benzonatate:
- Dizziness, headache, sedation, nausea
2) Dextromethorphan:
- Dizziness, drowsiness, nausea
3) Opioids (Codeine + Hydromorphone):
- Sedation, nausea, vomiting, lightheadedness, constipation
What is the primary function of the expectorants?
To break down and thin out the secretions.
