DESCRIPTION

Ethchlorvynol (Placidyl) is a sedative-hypnotic agent that is neither a barbiturate nor benzodiazepine.

FORMS AND USES

Available as 200-, 500-, or 750-mg capsules.

TOXIC DOSE

Acute ingestion of several grams may result in death.

PATHOPHYSIOLOGY

• Habituation occurs with chronic use.
• Withdrawal may last as long as 2 weeks following cessation of ethchlorvynol use and is similar in presentation and management to withdrawal from other sedative-hypnotic agents.

EPIDEMIOLOGY

Poisoning is uncommon.

CAUSES

• The drug is most commonly encountered as a drug of abuse.
• Child neglect should be considered if the patient is under 1 year of age; suicide attempt if the patient is over 6 years of age.

PREGNANCY AND LACTATION

• 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 either animals or women.
• Withdrawal syndrome may occur in neonates born to mother who uses ethchlorvynol.

DRUG AND DISEASE INTERACTIONS

CNS depression from ethchlorvynol is enhanced by the use of other sedative-hypnotic agents.

Section Outline:

• DESCRIPTION
• FORMS AND USES
• TOXIC DOSE
• PATHOPHYSIOLOGY
• EPIDEMIOLOGY
• CAUSES
• PREGNANCY AND LACTATION
• DRUG AND DISEASE INTERACTIONS

DIFFERENTIAL DIAGNOSIS

Any cause of CNS and respiratory depression.

SIGNS AND SYMPTOMS

• Patients typically present with varying degrees of sedation following ethchlorvynol use.
• The patient often has a characteristic odor that is similar to a new car or shower curtain vinyl odor.
• Characteristic pink or green pills and gastric aspirate may help identify the presence of ethchlorvynol.

Vital Signs

• Hypothermia and coma may occur with severe overdose.
• Coma and respiratory depression may last several days.

HEENT

Mydriasis is common.

Dermatologic

Bullous dermal lesions also may occur.

Cardiovascular

• Tachycardia is common, but bradycardia may develop if hypertension occurs.
• Hypotension may occur with severe overdose.

Pulmonary

Respiratory depression, apnea, aspiration pneumonia, and pulmonary edema may occur with severe overdose.

Fluids and Electrolytes

Following severe overdose, patients are often dehydrated.

Musculoskeletal

Rhabdomyolysis may occur with severe overdose.

Neurologic

• CNS depression leading to coma occurs commonly following overdose.
• Delirium also may occur during recovery.

PROCEDURES AND LABORATORY TESTS

Essential Tests

No tests are usually needed in asymptomatic patients.

Recommended Tests

• Pulse oximetry or arterial blood gas to evaluate oxygenation
• Serum electrolytes, BUN, creatinine, and glucose in patients with altered mental status
• ECG, serum acetaminophen, and aspirin levels in an overdose setting to screen for occult ingestion
• Head CT, lumbar puncture, bacterial cultures, and other tests in patients with altered mental status of unknown etiology

Section Outline:

• DIFFERENTIAL DIAGNOSIS
• SIGNS AND SYMPTOMS
  • Vital Signs
  • HEENT
  • Dermatologic
  • Cardiovascular
  • Pulmonary
  • Fluids and Electrolytes
  • Musculoskeletal
  • Neurologic
• PROCEDURES AND LABORATORY TESTS
  • Essential Tests
  • Recommended Tests

Treatment should focus on supportive and symptomatic care.

• Oxygen should be administered and the airway closely monitored.
• The patient should be intubated if respiratory compromise occurs.
• Intravenous access must be established following severe overdose.

DIRECTING PATIENT COURSE

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

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

Admission Considerations

Admit patients who cannot care for themselves safely.

DECONTAMINATION

Out of Hospital

Emesis should not be induced.

In Hospital

One dose of activated charcoal (1-2 g/kg) should be administered without a cathartic if a substantial ingestion has occurred within the previous few hours.

ANTIDOTE

There is no specific antidote for ethchlorvynol.

ADJUNCTIVE TREATMENT

• Patients with hypotension, bradycardia, and hypothermia typically respond readily to securing the airway, administering intravenous fluids, and passive rewarming.
• Hypotension should be treated with isotonic fluid infusion and the Trendelenburg position. A vasopressor may be needed; dopamine is preferred. Norepinephrine may be added for refractory hypotension.

Section Outline:

• DIRECTING PATIENT COURSE
  • Admission Considerations
• DECONTAMINATION
  • Out of Hospital
  • In Hospital
• ANTIDOTE
• ADJUNCTIVE TREATMENT

PATIENT MONITORING

It is important to continuously monitor cardiovascular function and oxygen saturation.

EXPECTED COURSE AND PROGNOSIS

• Patients who have not suffered sequelae such as anoxia prior to access to medical care typically recover uneventfully.
• Withdrawal syndrome may last up to 2 weeks.

DISCHARGE CRITERIA AND INSTRUCTIONS

Patients may be discharged from the emergency department or hospital when toxic effects resolve or stabilize following decontamination, and after psychiatric evaluation, if needed.

Section Outline:

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

Patient may have a flat EEG and yet fully recover.

FOLLOW-UP

Coma and respiratory compromise from ethchlorvynol poisoning may last for days following severe overdose.

Poisoning by sedatives and hypnotics.

RECOMMENDED READING

Teehan BP, Maher JF, Carey JJ, et al. Acute ethchlorvynol (Placidyl) intoxication. Ann Intern Med 1970;72:875-882.

Author: Lada Kokan

Reviewer: Richard C. Dart