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Respiratory stimulants: Nursing Pharmacology

Notes

Notes

RESPIRATORY STIMULANTS
DRUG NAME
doxapram, caffeine (Cafcit, NoDoz), theophylline (Elixophylline, Theo-24), aminophylline
CLASS
Respiratory stimulants
MECHANISM of ACTION
  • Stimulate respiratory center in the brainstem and medulla  → respiratory stimulation
  • Phosphodiesterase enzyme inhibitors → bronchodilation
INDICATIONS
  • Asthma
  • Respiratory depression
  • Apnea of prematurity
ROUTE(S) of ADMINISTRATION
  • PO
  • IV
SIDE EFFECTS
  • Muscle tremors
  • Agitation, anxiety, irritability, insomnia
  • Hypertension, heart palpitations, tachycardia, ECG abnormalities
  • Gastrointestinal disturbances: nausea, vomiting, diarrhea
  • Theophylline overdose: arrhythmias, seizures
  • Caffeine (high doses to premature infants): intracranial hemorrhage
CONTRAINDICATIONS and CAUTIONS
  • Arteriosclerosis, cardiovascular disease, hypertension
  •  Pregnancy and breastfeeding
  • History of seizures
  • Hepatic or renal disease
  • Theophylline: drug interactions with beta blockers, phenytoin, beta adrenergic agonists, antidepressants, cimetidine, ciprofloxacin, tobacco smoke, and marijuana
NURSING CONSIDERATIONS
Assessment and monitoring 
Assessment
  • Vital signs, especially respiratory rate; SpO2, lung sounds
  • Laboratory test results: renal and hepatic function

Monitoring
  • Vital signs 
  • Serum drug concentration levels; not to exceed 20 mcg/mL
  • Side effects 
  • Evaluate therapeutic response: improved airflow and decreased respiratory effort

Client education
  • Purpose of medication: help them to breathe easier
  • Take medication in the morning, with or without food
    • Avoid taking at bedtime
  • Avoid smoking, alcohol, and dietary sources of caffeine, like coffee, tea, soda, and chocolate
  • Side effects to report
    • Nausea, irritability, anxiety, tachycardia, palpitations, insomnia, nausea
      • If side effects are persistent or severe
    • Symptoms of toxicity: dizziness, lightheadedness, fatigue, weakness, shortness of breath
Transcript

Respiratory stimulants are a group of medications that can be administered to clients with asthma, chronic obstructive pulmonary disease or COPD for short, or respiratory depression; as well as to treat apnea of prematurity.

Respiratory stimulants include doxapram, which is administered intravenously, as well as certain phosphodiesterase enzyme inhibitors, also known as methylxanthines, such as caffeine, theophylline, and aminophylline, which are most often taken orally, but they can also be given intravenously.

Once administered, these medications primarily work on the brainstem and medulla by stimulating the respiratory center, and thus act as respiratory stimulants.

In addition, methylxanthines can also act on the lungs by inhibiting the phosphodiesterase enzyme, and ultimately cause bronchodilation.

Side effects commonly caused by respiratory stimulants include muscle tremors, agitation, anxiety, irritability, and insomnia. Clients might also experience gastrointestinal disturbances like nausea, vomiting, and diarrhea.

These drugs may also cause hypertension, heart palpitations, tachycardia, and ECG abnormalities.

In addition, theophylline has a very narrow therapeutic window, meaning it's very easy to overdose, and can cause arrhythmias or seizures.

Finally, administering high doses of caffeine to premature infants can lead to intracranial hemorrhage.

As far as contraindications go, respiratory stimulants are contraindicated in clients with severe arteriosclerosis, symptomatic cardiovascular disease, and moderate to severe hypertension.

Respiratory stimulants should also be avoided in clients with a history of seizures, as well as hepatic or renal disease.

Additional precautions should be taken during pregnancy and breastfeeding. Regarding interactions, theophylline and phenytoin should not be used together, as they decrease each other’s effects.

Finally, theophylline should not be combined with beta blockers, beta adrenergic agonists, antidepressants, H2 blockers like cimetidine, or certain antibiotics like ciprofloxacin, as well as tobacco smoke and marijuana, since these medications can increase the levels of theophylline and result in toxicity. Due to the dangerous potential side effects, theophylline is now rarely used.

Now, when caring for a client who is prescribed a respiratory stimulant like theophylline to improve their respiratory function, first perform a baseline assessment, including vital signs, especially respiratory rate, as well as SpO2, and lung sounds. Then, review your client’s recent laboratory test results, including renal and hepatic function.

Sources
  1. "Focus on Nursing Pharmacology" LWW (2019)
  2. "Pharmacology: A Patient-Centered Nursing Process Approach (8e)" Elsevier Health Sciences (2014)
  3. "Mosby's 2021 Nursing Drug Reference" Mosby (2020)
  4. "Saunders Comprehensive Review for the NCLEX-RN® Examination (7e)" Saunders (2017)
  5. "Goodman & Gilman’s The Pharmacological Basis of Therapeutics, 13th ed." McGraw-Hill Education (2018)