From the Guidelines
Benzonatate's common side effects include drowsiness, dizziness, headache, mild stomach upset, constipation, and a temporary numbing sensation in the mouth or throat. According to a case study by Doona and Walsh [@48@], benzonatate has been shown to improve cough symptoms in patients with advanced cancer. The medication works by numbing stretch receptors in the lungs, reducing the cough reflex. Less common but more serious side effects may include confusion, hallucinations, allergic reactions (rash, itching, swelling), and chest tightness.
Some key points to consider when taking benzonatate include:
- The capsules should never be chewed or dissolved in the mouth, as this can cause severe numbing of the throat and potential choking.
- If you experience difficulty breathing, severe dizziness, or allergic reaction symptoms, seek immediate medical attention.
- The medication typically begins working within 15-20 minutes and its effects last for 3-8 hours.
- Benzonatate is generally taken three times daily as directed by a healthcare provider, and it's essential to swallow the capsules whole with water to avoid the numbing sensation in the mouth.
It's worth noting that while the evidence for benzonatate's efficacy and side effects is largely based on case studies and lower-quality trials [@48@, @47@], the available data suggest that it can be an effective and relatively safe option for managing cough symptoms in certain patient populations. However, as with any medication, it's crucial to carefully weigh the potential benefits and risks and to closely monitor patients for any adverse effects.
From the FDA Drug Label
ADVERSE REACTIONS Potential Adverse Reactions to BENZONATATE may include: Hypersensitivity reactions including bronchospasm, laryngospasm, cardiovascular collapse possibly related to local anesthesia from chewing or sucking the capsule. CNS: sedation; headache; dizziness; mental confusion; visual hallucinations. GI: constipation; nausea; GI upset. Dermatologic: pruritus; skin eruptions. Other: nasal congestion; sensation of burning in the eyes; vague "chilly" sensation; numbness of the chest; hypersensitivity. WARNINGS Hypersensitivity Severe hypersensitivity reactions (including bronchospasm, laryngospasm and cardiovascular collapse) have been reported which are possibly related to local anesthesia from sucking or chewing the capsule instead of swallowing it. The common side effects of benzonatate include:
- Hypersensitivity reactions: bronchospasm, laryngospasm, cardiovascular collapse
- CNS effects: sedation, headache, dizziness, mental confusion, visual hallucinations
- GI effects: constipation, nausea, GI upset
- Dermatologic effects: pruritus, skin eruptions
- Other effects: nasal congestion, sensation of burning in the eyes, vague "chilly" sensation, numbness of the chest, hypersensitivity 1 1
From the Research
Common Side Effects of Benzonatate
The common side effects of benzonatate are not well-documented in the provided studies, as they primarily focus on the toxicity and overdose effects of the medication. However, based on the available information, some possible side effects of benzonatate include:
- Seizures 2, 3, 4
- Cardiac arrest 2, 3, 4
- Dysrhythmias 2
- Coma 3
- Brain edema or anoxic encephalopathy 3
- Apnea 3
- Tachycardia 3
- Respiratory arrest 3
Overdose Symptoms
In cases of overdose, benzonatate can cause severe symptoms, including:
- Rapid onset of toxicity, often within 15 minutes of ingestion 3
- Seizures and cardiac arrest 2, 3, 4
- Neurologic devastation and poor outcome in resuscitated patients 2
Safety Concerns
The provided studies highlight the safety concerns associated with benzonatate, particularly in children and adults who intentionally or unintentionally ingest the medication. The studies suggest that:
- Benzonatate can be lethal in acute overdose, even in small amounts 2
- Children under the age of 10 are at risk of accidental ingestion and overdose 3
- Intentional ingestion of benzonatate is increasing among children aged 10-16 years old 5
- Rational prescribing and improved provider and caregiver awareness of benzonatate toxic effects may reduce risks associated with benzonatate exposure 5