We all know the feeling—a throbbing in your throat that won’t go away. Coughing offers only a momentary respite as your sore throat worsens throughout the day. At times like these, many of us reach for a soothing lozenge to calm the irritation and provide some relief, at least for a short while.
But what about when the tickle comes back and you reach for another throat lozenge? How many cough drops is too many cough drops? And what’s the worst that can happen if you go overboard?
Dr. Kait Brown, clinical managing director at America’s Poison Centers, assures that dangerous cough drop overdoses are extremely rare. But that doesn’t mean we should pop them like candy.
“What we get concerned about is the menthol within the cough drops, and rarely there may be some that have benzocaine, which is a local anaesthetic,” she says. In very high doses, these ingredients can cause symptoms, including vomiting, dizziness, and even seizures.
Menthol-based cough drops can soothe but also irritate
Menthol is an organic compound derived from peppermint or eucalyptus oils. In moderate doses, it acts as a counterirritant, producing a cooling and numbing effect on the inner throat. But if used to excess, the same compound can start to irritate the body’s mucus membranes.
One study by the Wisconsin Research and Education Network found that high menthol consumption was associated with longer-lasting coughs. Although more research is needed, this could suggest that irritation from cough drop overuse can prevent a cough from healing.
Extreme menthol overuse can also produce acute symptoms. “With larger doses, which is rare, we can see early symptoms that are more gastrointestinal in nature, so some nausea or vomiting,” Dr Brown says. “That’s from irritation of the stomach mucus membrane when you swallow those cough drops.
If these early symptoms are ignored, menthol’s pleasant numbing sensation can become dangerous.
“At really high doses it can affect neural transmission from those receptors, which could then result in neurological symptoms,” Brown explains. “Severe symptoms of a large menthol overdose would include things like confusion or changes in mental state, getting a little more sleepy or dizzy. And really severe cases would be things like seizures.”
It’s very, very hard to overdose on cough drops
Thankfully, it is not easy to consume enough cough drops to put you at risk of menthol toxicity.
A typical cough drop contains five to 10 mg of menthol. Toxicologists consider a lethal dose of menthol to be 50 to 150 mg per kilogram of body weight, although some estimates put the figure as high as 1,000 mg per kilogram.
This means that an adult weighing 170 pounds would have to eat 400 menthol-rich cough drops in a sitting to reach even the lowest threshold for a lethal dose. Considering that there’s usually only 20 to 30 cough drops in a standard bag, that’d be the equivalent of going through at least 13 full bags of lozenges.
MaxBaumann / Getty Images MaxBaumannReported deaths from menthol overdose are extremely rare. One of the only cases in the medical literature involved a worker in India who died suffering from seizures and kidney failure ten days after cleaning a tank in a peppermint factory.
Another extreme case involved an 86-year-old man who was found unconscious by neighbors and rushed to the emergency room suffering from weakness, muscle ache, disorientation, ulcers, and heartburn. He admitted to consuming two bags of cough drops a day for twenty years, suggesting potential risks from chronic overuse.
Although some unpleasant side effects could be expected at much less excessive doses, most adults are unlikely to reach this level just to get them through a cold or flu.
“There’s a relative margin of safety with the menthol-based cough drops,” Brown says. She prefers not to estimate a safe quantity, for fear of promoting unhealthy usage, but stresses that “if you follow the instructions on the packet, you’re going to be within a window of safety.”
Why benzocaine makes cough drops more dangerous
Brown cautions that particular care is necessary if using cough drops containing benzocaine or other local anaesthetics.
“We don’t largely see benzocaine in these preparations anymore because of the risk of overdose associated with it,” she says.
“You can get a condition called methemoglobinemia, which changes the capacity of your blood to carry oxygen. You can end up having too little oxygen delivered to your cells and that can result in things like bluing of the lips and hands and can be life-threatening.”
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What to do for a cough drop overdose
If anyone is worried that they’ve overused cough drops, Brown recommends contacting the America’s Poison Centers helpline at 1-800-22-1222. This is a national nonprofit service that advises Americans worried about exposure to common toxins.
“There are healthcare professionals with extra toxicology training that can walk you through that specific scenario,” Dr Brown explains. “They can recommend that you stay home, or they’ll let you know if you need to seek a higher level of care.”
During her work at America’s Poison Centers, she says she has received many calls about cough drops, mostly from people reporting mild symptoms or just wanting to discuss incidents of potential overuse.
“It’s children we get most concerns about, because they’re most likely to use the product inadvertently,” she says. Although it is rare for children to consume enough cough drops to cause acute symptoms, she advises always leaving the product out of reach of children—and sometimes adults as well.
“When people are sick, maybe they don’t have the energy to think as clearly as they normally would,” she says.
“We caution people that if you know you’re going to be using cough drops all day, take out the allotted amount that the package says you can have. That way you know you’re not exceeding the quantity you can safely use.”
But if you do have a few extra drops, there’s no need to panic—you’ll probably be just fine.
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