DESCRIPTION

Guaifenesin is an oral expectorant used in the treatment of cough.

FORMS AND USES

• Guaifenesin is available as Anti-Tuss, Breonesin, Diabetic Tussin Ex, Fenesin, Gee-Gee, Genatuss, GG-Cen, Glyate, Glycotuss, Glytuss, GuiaCough Expectorant, Guiatuss, Halotussin, Humibid LA, Humibid Sprinkle, Hytuss, Luquibid, Malotuss, Medi-Tuss, Mytussin, Naldecon Senior EX, pneumomist, Respa-GF, Robitussin, Scot-Tussin, Silutussin, Sinumist-SR Capsulets, TouroEx, and Uni-Tussin.
• Many products contain alcohol, dextromethorphan, or opioids in addition to guaifenesin.

TOXIC DOSE

The toxic dose for guaifenesin alone is unknown, but it is very high.

PATHOPHYSIOLOGY

Guaifenesin acts by stimulating respiratory tract secretions.

PREGNANCY

US FDA Pregnancy Category C. The drug exerts animal teratogenic or embryocidal effects, but there are no controlled studies in women, or no studies are available in animals or women.

Section Outline:

• DESCRIPTION
• FORMS AND USES
• TOXIC DOSE
• PATHOPHYSIOLOGY
• PREGNANCY

DIFFERENTIAL DIAGNOSIS

Other toxic causes of CNS depression include opioids, ethanol and many other agents.

SIGNS AND SYMPTOMS

Nausea, vomiting and lethargy may be observed. In severe cases, depression and coma may develop.

LABORATORY TESTS

Essential Tests

• No tests may be needed for asymptomatic patients.
• Serum electrolytes, BUN, glucose and creatinine are ordered to assess causes of altered mental status.
• ECG, serum acetaminophen and aspirin levels should be determined to detect occult overdose.

Section Outline:

• DIFFERENTIAL DIAGNOSIS
• SIGNS AND SYMPTOMS
• LABORATORY TESTS
  • Essential Tests

• Treatment should focus on decontamination and supportive care of respiration.
• Dose and time of ingestion must be determined for all substances involved.

DIRECTING PATIENT COURSE

The health-care professional should call the poison control center when:

• Toxic effects are not consistent with gold toxicity.
• Coingestant, drug interaction, or underlying disease presents an unusual problem.

The patient should be referred to a health-care facility when:

• Suicide or homicide attempt is possible.
• Coingestant, drug interaction, or underlying disease presents an unusual problem.

DECONTAMINATION

Out of Hospital

Emesis need not be induced unless toxic coingestant is present.

In Hospital

• Emesis should not be induced.
• Gastric lavage would not be expected to be helfpul, because these products are typically liquids.
• One dose of activated charcoal (1-2 g/kg) should be considered if a substantial ingestion has occurred within the past hour.

ANTIDOTES

There is no specific antidote for guaifenesin poisoning.

ADJUNCTIVE TREATMENT

General supportive care is provided.

Section Outline:

• DIRECTING PATIENT COURSE
• DECONTAMINATION
  • Out of Hospital
  • In Hospital
• ANTIDOTES
• ADJUNCTIVE TREATMENT

PATIENT MONITORING

In severe cases, heart rate, blood pressure, ECG, serum electrolytes, arterial blood gases, and serum creatinine should be monitored.

EXPECTED COURSE AND PROGNOSIS

Symptoms rarely appear unless large amounts are ingested. Prognosis is excellent, and recovery is expected within 24 hours with supportive treatment.

DISCHARGE CRITERIA/INSTRUCTIONS

Patients may be discharged from the emergency department or hospital provided they do not develop symptoms of toxicity after 6 hours of observation and have undergone a psychiatric evaluation, if needed.

Section Outline:

• PATIENT MONITORING
• EXPECTED COURSE AND PROGNOSIS
• DISCHARGE CRITERIA/INSTRUCTIONS

Guaifenesin-containing products often also contain alcohol, dextromethorphan, or opioids.

Poisoning by agents primarily affecting skin and mucous membrane: ophthalmologic, otorhinolaryngologic, and dental drugs.

Author: Kevin M. Lier

Reviewer: Richard C. Dart