seen such increases when winter arrives. This section of the subcourse will discuss
some respiratory systems medications commonly seen in the pharmacy.
1-16. ANTITUSSIVE AGENTS
a. Background. Antitussives are agents that relieve or prevent coughing.
These agents, in general, act on the central nervous system to depress the cough reflex
center in the medulla of the brain. Antitussives are used to reduce respiratory irritation.
Such reduction of respiratory irritation results in the patient's being able to rest better at
night because he is not kept awake by his coughing.
b. Antitussive Agents.
(1) Codeine. Codeine is considered to be the most useful narcotic
antitussive agent. Codeine aids in relieving the pain (that is, producing analgesia)
associated with a hacking cough. The main side effects associated with codeine
include drowsiness, nausea, vomiting, and constipation. When a preparation containing
codeine is dispensed to a patient that patient should be told that the product may cause
drowsiness, and that he should not drink alcohol while taking the medication. Codeine
is a Note R drug alone and cannot be refilled. It is a Note Q item when it is found in
combination products (for example: Robitussin A-C Syrup). The usual oral dosage of
codeine alone is 15 milligrams (1/4 grain) every 4 to 6 hours as needed for cough. The
dosage can be increased but should not exceed 120 milligrams in 24 hours because of
its central nervous system (CNS) depressant effects.
(2) Benzonatate (Tessalon). Benzonatate is a nonnarcotic antitussive that
produces its effect through a CNS depressant effect similar to codeine. Furthermore, it
produces a local anesthetic effect on the stretch receptors in the lower respiratory tract,
which control coughing. Benzonatate is usually given in 100 milligram doses--three to
six times daily. This drug has few side effects except that it will numb the mouth,
tongue, and pharynx if the capsules are chewed (this is because of its topical anesthetic
effect). Benzonatate is available in the form of 100 milligram capsules.
(3) Dextromethorphan, DM (Pertussin CS). Dextromethorphan is another
non-narcotic antitussive. It is found alone or in combination--usually with expectorants.
The most common side effect associated with this drug is gastrointestinal (G.I.) upset.
Dextromethorphan is a non-legend drug, which may be written as a prescription drug or
as a hand-out item depending on the local policy of your hospital. The usual oral
dosage of this drug is 10 to 30 milligrams, every four to eight hours. Do not exceed
120mg in 24 hours. There are many products on the market, which contain
dextromethorphan in combination. Examples of such products include Robitussin-DM