Common Antitussives and Generic Names
- benzonatate (Tessalon)
- codeine
- dextromethorphan (Benylin)
- hydrocodone (Hycodan)
Disease Spotlight: The Common Cold
Cold viruses invade the upper respiratory tract and trigger histamine and prostaglandin release, driving an inflammatory response. Mucous membranes engorge with blood, tissues swell, and goblet cells ramp up mucus production. The patient complains of sinus pain, nasal congestion, runny nose, sneezing, watery eyes, scratchy throat, and headache. If the swelling blocks the eustachian tube outlet (which drains the inner ear and equalizes pressure across the tympanic membrane), expect ear stuffiness and pain.
What Antitussives Do
Antitussives act on the cough-control center in the medulla to suppress the cough reflex. Reach for them when the cough is nonproductive and irritating.
Therapeutic Action
These drugs act directly on the medullary cough center to depress the cough reflex. Because they are centrally acting, they are not the drugs of choice for anyone with a head injury or anyone who could be impaired by CNS depression.
Indications
- Local anesthetic on the respiratory passages, lungs, and pleurae, blocking the stretch receptors that trigger the cough reflex.
- Relief of moderate to moderately severe pain.
- Treatment of dry cough, drug withdrawal syndrome, opioid-type drug dependence, and pain.
Pharmacokinetics
Codeine, hydrocodone, and dextromethorphan are rapidly absorbed, metabolized in the liver, and excreted in urine. They cross the placenta and enter breast milk.
Contraindications and Cautions
- Patent airways. Patients who need to cough to maintain the airway (postoperative patients, abdominal or thoracic surgery) risk respiratory distress.
- Asthma and emphysema. Cough suppression can lead to secretion buildup and loss of respiratory reserve.
- Addiction. Patients hypersensitive to narcotics or with a history of addiction. Codeine is a narcotic and carries addiction potential.
- Sedation. Patients who need to drive or stay alert should use codeine, hydrocodone, and dextromethorphan with extreme caution. These drugs cause sedation and drowsiness.
- Pregnancy and lactation. Risk of adverse effects on the fetus or baby, including sedation and CNS depression.
Adverse Effects
- CNS: drowsiness, sedation.
- GI: nausea, constipation, dry mouth, GI upset.
Interactions
- MAOIs. Do not combine dextromethorphan with MAOIs. Hypotension, fever, nausea, myoclonic jerks, and coma can occur.
Nursing Considerations
Assessment
- Screen for contraindications and cautions: drug allergy, cough lasting more than 1 week, pregnancy, and lactation.
- Perform a physical exam for baseline data.
- Monitor temperature to catch an underlying infection.
- Assess respirations and adventitious sounds.
- Evaluate orientation and affect.
Nursing Diagnoses
- Ineffective airway clearance related to excessive drug effects.
- Disturbed sensory perception related to CNS effects.
- Deficient knowledge regarding drug therapy.
Interventions
- Prevent overdose. Do not let the patient take the drug longer than recommended. Overuse risks serious adverse effects and worsening respiratory tract problems.
- Assess underlying problems. Arrange further medical evaluation for coughs that persist or come with high fever, rash, or excessive secretions, so the underlying cause gets treated.
- Offer other relief. Humidify the room, push fluids, use lozenges, and cool the room temperature.
- Teach the patient. Cover the drug name, prescribed dose, how to avoid adverse effects, and warning signs that signal a problem.
- Support the patient. Help them cope with the illness and the regimen.
Evaluation
- Monitor response (control of nonproductive cough).
- Monitor for adverse effects (respiratory depression, dizziness, sedation).
- Evaluate the teaching plan.
- Check that other cough-relief measures are working.
Frequently Asked Questions
How do antitussives suppress a cough? Centrally acting agents like dextromethorphan and the opioids (codeine, hydrocodone) work in the cough center of the brainstem; dextromethorphan blocks NMDA-type glutamate receptors in the medullary pathways that drive the cough reflex (StatPearls). Benzonatate works peripherally, anesthetizing the stretch receptors in the lungs and airways.
When should a cough not be suppressed? When it is productive. Coughing clears the airway of secretions, so suppressing a wet, productive cough can trap mucus and worsen the patient. Antitussives are for the dry, hacking, nonproductive cough that exhausts the patient and irritates the airway.
Why is dextromethorphan preferred over codeine for routine cough? Dextromethorphan controls cough without the analgesia, sedation, or dependence risk of opioids. Codeine and hydrocodone are reserved for situations where a stronger agent is justified and are watched for respiratory depression.
Why must benzonatate capsules be swallowed whole? Benzonatate numbs on contact. If chewed or sucked, it can anesthetize the mouth and throat and suppress the gag reflex, risking choking. Teach the patient to swallow it intact.
What teaching prevents masking a serious problem? A cough lasting more than about a week, or one with high fever, rash, or persistent headache, should be evaluated rather than self-treated, since it may signal an infection or other condition needing treatment (StatPearls).
What comfort measures help alongside the drug? Humidified air, increased fluids, sugarless lozenges, and avoiding airway irritants like smoke ease a dry cough and reduce reliance on the suppressant.