Does Propofol Cause Coughing? Anesthetic Side Effects Explained

Paradoxically, while often used to suppress airway reflexes, propofol administration can itself induce a violent, albeit brief, coughing spell in some patients [1.2.4, 1.3.1]. This article explores the question: Does propofol cause coughing, and what factors influence this common but unexpected side effect during anesthesia?

Quick Summary

An in-depth look at propofol-induced coughing, covering its incidence, the physiological mechanisms that trigger it, and the pharmacological strategies clinicians use to prevent and manage this common side effect during anesthesia.

Key Points

• Paradoxical Effect: Propofol is used to suppress airway reflexes but can also cause coughing upon induction, especially at high doses [1.3.1, 1.2.4].

• Incidence Rate: The incidence of propofol-induced cough can be as high as 70% with large doses (5 mg/kg of 2% propofol) [1.2.4].

• Primary Mechanism Theory: A leading theory suggests that sudden high concentrations of propofol in the brain trigger the cough reflex [1.5.2].

• Risk Factors: Smoking is a significant risk factor for coughing on emergence from anesthesia, regardless of the agent used [1.5.3].

• Prevention is Key: Pre-treatment with drugs like lidocaine, ketamine, or opioids can effectively reduce the incidence of anesthetic-related coughing [1.4.1, 1.4.3].

• Agent Comparison: Total intravenous anesthesia with propofol generally results in less emergence coughing compared to inhaled anesthetics like sevoflurane [1.5.3, 1.6.6].

• Administration Matters: Slower injection rates and the use of smaller, priming doses can help mitigate the cough reflex [1.2.8].

What is Propofol and Why is it Used?

Propofol is a powerful and widely used intravenous sedative-hypnotic agent essential for modern anesthesia [1.5.6]. Approved by the FDA in 1989, its popularity stems from its rapid onset of action, typically within seconds, and a short duration, allowing for smooth induction of general anesthesia and controlled sedation in intensive care units (ICU) [1.5.6]. Propofol is valued for its ability to decrease the incidence of gagging, coughing, and laryngospasm, providing intense suppression of airway reflexes during procedures like tracheal intubation [1.3.1, 1.6.3]. Beyond sedation, it also possesses anxiolytic (anxiety-reducing) and anticonvulsant properties [1.5.6].

The Paradox: Does Propofol Cause Coughing?

While propofol is known to inhibit airway reflexes, it can also paradoxically trigger a cough, sometimes a violent one, during the induction of anesthesia [1.3.1, 1.3.7]. This phenomenon is not to be confused with fentanyl-induced cough, a more widely studied reaction where propofol is actually used as a suppressant [1.2.1, 1.2.8]. The incidence of coughing specifically from propofol can be significant. One study reported a 70% incidence of coughing when using large doses of 2% propofol (5 mg/kg), though other studies with different dosages show no incidence [1.2.4]. This variability suggests that the dose and concentration play a crucial role.

Mechanisms Behind Propofol-Induced Cough

The exact reasons why propofol induces coughing are not fully understood, but several theories exist:

• High Brain Concentration: One leading hypothesis suggests that a rapid injection of high-dose propofol leads to a sudden high concentration in the brain, which may trigger the cough reflex [1.5.2, 1.5.4].
• Airway Muscle Contraction: An alternative theory proposes that propofol-induced apnea (a temporary pause in breathing) can lead to an increase in carbon dioxide levels (PaCO2) and acidemia. This change might cause airway smooth muscle contraction, stimulating irritant receptors in the tracheobronchial airways and inducing a cough [1.5.2, 1.5.4]. These irritant receptors are also sensitive to chemical and mechanical stimuli [1.5.2].
• Inhibition of NMDA Receptors: Propofol is thought to inhibit N-methyl-D-aspartate (NMDA) receptors in the brainstem. While this action is generally believed to suppress laryngeal reflexes, its complex interaction could potentially contribute to the cough reflex under certain conditions [1.3.2, 1.3.5].

Identifying Key Risk Factors

Several factors can increase a patient's risk of developing a cough during anesthesia emergence or induction:

• Smoking: Smokers are at an increased risk of coughing during emergence from anesthesia, regardless of whether propofol or another anesthetic like sevoflurane is used [1.5.3].
• Pre-existing Conditions: Patients with a history of asthma, chronic cough, or recent upper respiratory tract infections may be more susceptible [1.2.1]. Likewise, conditions like gastroesophageal reflux (GER) and snoring are considered risk factors for respiratory compromise during sedation [1.5.1].
• Anesthetic Choice and Concentration: The type and concentration of the anesthetic agent significantly influence cough probability. One study found that the incidence of severe coughing was dramatically higher with sevoflurane (59%) compared to propofol (6%) during emergence. However, higher residual concentrations of the anesthetic agent at the time of extubation tend to decrease the probability of coughing [1.5.3].

Prevention and Management Strategies

Clinicians employ several techniques to mitigate the risk of coughing associated with propofol and other anesthetic agents:

• Pharmacological Interventions: Pre-treatment with certain drugs is a common strategy. Intravenous lidocaine, opioids like fentanyl and remifentanil, dexmedetomidine, and ketamine have all been shown to reduce the incidence of coughing [1.4.1, 1.4.3, 1.4.5]. Combining a small dose of propofol with ketamine has also been found to be effective, particularly in decreasing severe coughing fits [1.2.5].
• Dose and Administration Technique: Slower injection speeds and using a priming dose—a small initial dose administered before the main induction dose—can help suppress the cough reflex. One study found that a priming dose of propofol (1.5 mg/kg) was effective in suppressing fentanyl-induced cough in a dose-dependent manner [1.2.8].
• Anesthetic Choice: Using total intravenous anesthesia (TIVA) with propofol has been associated with a lower prevalence of coughing during emergence compared to balanced anesthesia using inhaled agents like sevoflurane [1.4.2, 1.6.6].

Anesthetic Agent Comparison Table

Feature	Propofol	Ketamine	Sevoflurane (Inhaled)
Cough Suppression	Generally high, effective at suppressing airway reflexes [1.6.3].	Can reduce coughing, but some studies show it is less effective than propofol [1.6.2].	Associated with a higher incidence of severe coughing upon emergence compared to propofol [1.5.3].
Analgesic Effect	No [1.6.5].	Yes [1.6.5].	No.
Side Effects	Respiratory depression, potential for crying and coughing during procedure [1.6.5].	Can cause delirium, nausea, and muscle spasms during recovery [1.6.5].	Higher risk of emergence coughing, especially in smokers [1.5.3].
Use in Children	A small dose is effective in reducing emergence cough after tonsillectomy [1.6.2].	Less effective than propofol for preventing emergence cough in children [1.6.2].	Often used for maintenance of anesthesia [1.6.1].

Conclusion

Propofol holds a dual role concerning the cough reflex. While it is a potent suppressant of airway reflexes and is even used to prevent coughing caused by other drugs like fentanyl, it can paradoxically cause coughing itself, particularly with high doses or rapid administration [1.2.4, 1.4.6]. The mechanism is complex and likely involves a combination of high brain concentrations and stimulation of airway irritant receptors [1.5.2]. Factors like smoking and the choice of anesthetic agent significantly impact this risk [1.5.3]. Fortunately, anesthesiologists have a range of effective prevention strategies, including pharmacological pre-treatments with agents like lidocaine or ketamine and adjustments to the dose and rate of administration, to ensure patient safety and comfort during anesthesia [1.4.3, 1.4.5].

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For further reading on anesthetic pharmacology, consider this authoritative resource:

Propofol Infusion Syndrome in Adults: A Clinical Update

Frequently Asked Questions

Can propofol cause a cough even though it's supposed to suppress it?

Yes, paradoxically, propofol can induce a cough, particularly when administered in high doses or very rapidly. This is thought to be caused by a sudden high concentration of the drug in the brain or stimulation of airway irritant receptors [1.5.2, 1.5.4].

Is coughing from propofol dangerous?

While the cough is typically brief, it can be violent. This may be undesirable in patients with certain conditions like cerebral aneurysms, head trauma, or open eye injuries, where increases in pressure can be harmful [1.2.1].

How common is coughing with propofol?

The incidence varies widely depending on the dose and concentration. One study noted a 70% incidence with a high dose of 2% propofol, while other studies using different dosages reported no coughing episodes [1.2.4].

Are there ways to prevent a cough when getting propofol?

Yes, anesthesiologists use several methods, including slower injection speeds, administering a small 'priming' dose first, or pre-treating with medications like lidocaine, fentanyl, or ketamine to suppress the reflex [1.2.8, 1.4.3, 1.4.5].

Does smoking make coughing from anesthesia worse?

Yes, studies show that smokers are at an increased risk of coughing when emerging from general anesthesia, regardless of the primary anesthetic agent used [1.5.3].

Is propofol better or worse than other anesthetics for coughing?

Propofol is generally associated with a lower incidence of coughing upon emergence compared to inhaled anesthetics like sevoflurane. Studies show sevoflurane can lead to a significantly higher rate of severe coughing [1.5.3, 1.6.6].

What is the difference between fentanyl-induced cough and propofol-induced cough?

Fentanyl-induced cough is a known side effect of the opioid fentanyl. Propofol is actually used as an effective treatment to suppress fentanyl-induced cough [1.2.1]. Propofol-induced cough is a separate, paradoxical effect caused by the propofol itself [1.3.1].