Is It Possible to Overdose on Cough Drops?

Over-the-counter (OTC) cough drops are used to relieve coughs. They usually come in small candies or lozenges and have medicinal properties that help soothe a sore throat and reduce coughing. Due to their cooling effect, cough drops can relieve throat irritation caused by colds, inhaled irritants, and other mild to minor throat discomforts.

A common component in OTC cough drops is menthol, a white crystalline solid recognized for its peppermint odor and taste. Methanol helps soothe irritation by making you feel cool and slightly numb. It can be either synthesized or extracted from peppermint and other mint oils. Some cough drops may contain other medications that could cause problems if consumed in large quantities.

This article discusses the recommended number of cough drops you should consume, what to do if you have too many, and possible side effects.

Can You Take Too Many Cough Drops?

While cough drops can effectively ease throat discomfort, sticking to the recommended dose limits is important. As suggested by the OTC cough drop drug facts, it is advised not to consume more than 12 in 24 hours or more than one cough drop every two hours. Always check the package for dosage instructions or consult a healthcare provider for advice if you have any questions.

Cough drops vary in the amount of menthol they contain, with some common doses being 1.6 milligrams (mg), 5.4 mg, 7.5 mg, or 10 mg. Taking cough drops as recommended is safe, but large exposure to pure menthol can be risky. Even though it's rare, excessive consumption of cough drops can also lead to serious health issues.

In 2016, a tragic case was reported in which a worker sadly passed away from inhaling too much menthol while working in a peppermint factory. Another case of menthol poisoning was also discovered from an individual who had taken two bags of menthol cough drops every day for 20 years, leading to several skin, stomach, and nerve problems. If you believe you have consumed too much menthol, it's important to get medical help or call a Poison Control Center immediately.

Menthol Poisoning

Menthol poisoning can occur when someone consumes, inhales, or absorbs too much menthol, either from using products containing menthol or from accidental exposure to concentrated forms of menthol. Some examples of methanol products include cough drops and lozenges, Vicks VapoRub, Icy Hot, certain toothpaste and mouthwashes, peppermint oils, and some candies.

A potentially lethal amount of menthol can vary widely, ranging from 50 to 500 mg per kilogram (kg) of a person's body weight. For instance, a 154-pound (or 70-kg) person would need to ingest between 3,500 and 10,500 mg of menthol for it to be potentially fatal. According to The Natural Standards, an international integrative medical organization, a dose of up to 1 gram (g) per kg of body weight is considered deadly. In the case of the same individual, this equates to consuming 70,000 mg of menthol, which is seven to 20 times higher than the threshold of other cited sources. Excessive intake of menthol can lead to symptoms such as dizziness, nervousness, and nystagmus, which involves rapid and uncontrollable eye movements.

Side Effects of Taking Too Many Cough Drops

Menthol may cause side effects if taken in high doses. Side effects to look out for include feeling sick with nausea, vomiting, headaches, sleepiness, and stomach pain. Without proper and prompt treatment, an individual may risk experiencing a coma, seizures, or even death.

Here is a list of common symptoms associated with menthol toxicity:

• Nausea 
• Vomiting
• Headache
• Drowsiness
• Agitation
• Fatigue
• Stomach pain 
• Dizziness
• Nystagmus: rapid and uncontrollable eye movements
• Ataxia: poor muscle control that causes clumsy movements

Here are some severe symptoms:

• Imaginary visions or sensations
• Seizures
• Coma 
• Death
  

Allergic Reactions

Although uncommon, menthol can cause some allergic reactions. Menthol can be found in some common daily products such as cough drops, medicated creams, dental products, lip balms, medicinal rubbing oils, cigarettes, and chewing gums. While menthol is generally considered safe to apply on the skin or take by mouth under the recommended limit, exposure to menthol, whether through inhalation, ingestion, or skin contact, can lead to allergic reactions.

Typical symptoms include rash (urticaria), swelling, and skin irritations (dermatitis). Some people might be allergic to products like menthol cough drops without being aware of their allergy.

A person with pre-existing skin disorders, eye problems, or impaired respiratory function may be more susceptible to an allergy. Reports of such allergies have been documented with the use of cigarettes, toothpaste, ointments, and cough drops. Symptoms usually will go away once the use is stopped. 

Not everyone will have an allergy to menthol, but it's good to be cautious and check for allergies before using menthol products. In the event of a severe allergic reaction, such as anaphylaxis, immediately call 911 or your local medical emergency number.

When to Seek Medical Help

If there is known or suspected over-ingestion of menthol, immediate medical attention is necessary. Signs of menthol toxicity to watch for include nausea, vomiting, dizziness, nervousness, nystagmus, coma, and, in severe cases, death.

How Is Menthol Poisoning Treated?

In cases of high menthol exposure, it is critical to call 911 immediately. There is no antidote for menthol intoxication, so early recognition and supportive care are vital for recovery. Treatment primarily involves supportive measures, such as nasogastric lavage (stomach pumping) and intravenous fluids. The outcomes depend on many factors, such as how much methanol was ingested, how long the person was exposed, and how quickly the medical treatment is provided to the patient.

Summary

Cough drops should be used according to the package instructions or as advised by a healthcare professional, with a limit of 12 drops daily and no more than one drop every two hours. Always keep cough drops out of the reach of children, as they look like candy and present a choking hazard.

Excessive consumption of menthol-containing cough drops can be dangerous, potentially leading to symptoms like nausea, vomiting, headaches, and serious health issues such as seizures, coma, or even death.

If menthol poisoning is suspected from excessive use of cough drops or other products containing menthol, it is crucial to seek immediate medical help to avoid long-term health complications. If you have any questions about poison prevention, call the Poison Help Line.

The author would like to recognize and thank Norma Ponce, PharmD, MHA, for contributing to this article.