One of the most popular cough medicines in pharmacies for over 100 years was terpin hydrate. It was an expectorant, meaning that it was prescribed by physicians to loosen mucus and ease congestion. It was derived from compounds found in plants like oregano, thyme and eucalyptus. It was also manufactured from oil of turpentine. This was obtained from the resin of pine trees and used to be applied topically to joints and muscles to ease pain and inflammation. Many readers who remember terpin hydrate want to know what happened to it and how to obtain it. One reader offered this:
What Happened to Terpin Hydrate?
Q. Most people think that the old-fashioned cough medicine terpin hydrate has been banned. That’s not true. Although it’s no longer kept in stock at pharmacies, it can be special ordered from a compounding pharmacy.
Four years ago I came down with a bad cold and wicked cough. I asked my doctor if he could write a prescription for terpin hydrate and was surprised that he was willing to do so. I contacted my local compounding pharmacy and they said they don’t carry it in stock but they would place a special order. They filled my prescription.
Last week I came down with another bad cold and was coughing constantly. I went back to my doctor, who asked if the terpin hydrate had worked. When I said yes, he rewrote the prescription and the pharmacy filled it. Within 48 hours it made a HUGE difference, instead of taking three weeks for the cough to run its course.
A. Terpin hydrate was a popular cough medicine in the early 1900s. By the late 1980s, however, the FDA found inadequate evidence to support continued sales.
Update from the FDA:
On April 1, 2016 the FDA stated:
“A number of active ingredients have been present in OTC drug products for various uses, as described below. However, based on evidence currently available, there are inadequate data to establish general recognition of the safety and effectiveness of these ingredients.”
Under the category of “Expectorant drug products” is “Terpin hydrate preparations.”
As a result of an FDA ruling terpin hydrate pretty much disappeared from pharmacy shelves in the 1980s. An FDA staffer confided to me decades ago that he personally used terpin hydrate and found it helpful. Nevertheless, the agency decided it was inappropriate for OTC cough and cold remedies. There just wasn’t adequate data demonstrating effectiveness. Apparently no drug company was willing to invest in new research.
We’re Left with Guaifenesin:
Pretty much the only expectorant left on pharmacy shelves was guaifenesin. It can be found in lots of cough and cold remedies. The independent Cochrane Collaboration reviews the evidence behind many drugs. In its analysis of OTC cough medicine (Cochrane Database of Systematic Reviews, Nov. 24, 2014) it reported:
“Three trials compared the expectorant guaifenesin with placebo; one indicated significant benefit, whereas the other two did not…There is no good evidence for or against the effectiveness of OTC medicines in acute cough.”
That’s hardly a ringing endorsement. One might go so far as to wonder how the FDA gave guaifenesin the green light if the data were equivocal.
Another article in the journal Respiratory Care (July, 2007) noted:
“Although expectorants, such as guaifenesin (eg, Robatussin or Mucinex), are sold over the counter, there is no evidence that they are effective for the therapy of any form of lung disease, and when administered in combination with a cough suppressant such as dextromethorphan (the “DM” in some medication names) there is a potential risk of increased airway obstruction.”
What About Terpin Hydrate?
As the reader reported, terpin hydrate disappeared from pharmacy shelves but compounding pharmacies may still make and dispense it. Many readers remember it to be quite helpful for calming a hard-to-treat cough.
Other comments from readers:
Emily shared this story:
“I used to carry Terpin Hydrate Elixir in my music bag and found it very helpful before voice lessons and singing engagements. It was available at the time at pharmacies w/o Rx (non-codeine), and 1 tsp in a glass of water, or even undiluted tasted like Cointreau (orange liqueur)! I hoarded the last bit when it became unavailable — I may even still have a bottle with dregs in it!”
Brian from the UK offers this:
“Terpin Hydrate and Codeine is still available from chemists [pharmacists] without prescription over here in England. Having had a deep chesty cough for the last fortnight, I found the terpin & codeine mixture was far more soothing, especially at night, than just codeine on its own. Apart from the physical sensation of cooling my throat and lungs I couldn’t really say if it was overly effective in producing anything more than short-term relief.
“The authorities must think that terpin does something, as the daily dosage for terpin & codeine is three eighths of the dosage of codeine on its own. So, effective or otherwise, I’m grateful that they haven’t yet banned it on this side of the water!”
What Else Can you Do for a Cough?
We are not big defenders of terpin hydrate. We agree with the folks at Cochrane that data are lacking to prove effectiveness. What we do like is thyme tea. We brew up a cup with half a teaspoon of dried thyme leaves from our kitchen spice rack. We let the thyme leaves steep for several minutes, remove and add a bit of honey. We find this old-fashioned cough remedy to be quite helpful.
If you would like to learn more about other ways to calm a cough we recommend our Guide to Colds, Coughs & the Flu. You will find other suggestions for kicking a cough.
Share your own experience with terpin hydrate, thyme or other remedies below in the comment section.