Cold-Cough

Benzonatate

Guaifenesin

Promethazone

Phenylephrine

Expectorants

• Indication: can be considered for productive coughs

• Mechanism of action

  • Increase bronchial fluid to reduce viscosity of mucus (no cough suppression)

  • The exact mechanism is unknown.

• Guaifenesin

  • Side effects include nausea and headache

  • Symptoms of overdose include vomiting, altered mental status (due to depression of the central nervous system)

Can be considered for nocturnal dry cough

• Peripherally acting: suppress peripheral triggers of the cough reflex arc by anesthetizing respiratory stretch receptors

  • Benzonatate

    • A local anesthetic with cough suppressing properties which is administered as capsules

    • Side effects: e.g., nausea, dizziness, headache, altered mental status

    • Symptoms of overdose: visual disturbances, tremor, seizures

First-generation H1 antihistamine

Promethazine also acts as a low-potency antipsychotic, because it antagonizes dopamine D2 receptors. In addition, it has nominal alpha blocker and local anesthetic action. Contraindicated in children < 2 years of age, as it may lead to fatal respiratory depression.

Direct sympathomimetic drug

• Raises BP (through vasoconstriction α1 > α2)

• Lowers HR

• No change or decrease in CO

Indication:

• Hypotension

• Rhinitis, obstructed Eustachian tubes

• Phenylephrine acts as a nasal decongestant by reducing hyperemia and mucosal edema

• Allergic conjunctivitis

• Open-angle glaucoma

• Ischemic priapism (high-dose intracavernosal phenylephrine injection)