Please explain the difference between pseudoephedrine and phenylephrine, in particular why one works better than the other at different times.
Pseudoephedrine vs. Phenylephrine?
Question posted by GKDdrugs on 13 Jan 2010
Last updated on 21 September 2017
This question has also been asked and answered here: Phenylephrine vs Pseudoephedrine - How do they compare?
4 Answers
sewillerton
14 Sep 2016
From a pharmacist at Walgreens:
What's the difference between phenylephrine and pseudoephedrine? Do they work the same?
Both pseudoephedrine and phenylephrine are decongestants used to treat nasal congestion due to allergies, colds, sinus infections, etc. Since pseudoephedrine can be made into methamphetamine, the U.S. Senate passed a bill restricting its sale. Pseudoephedrine products can still be purchased in limited quantities, but identification and signatures are required. Some states also require a prescription for pseudoephedrine products.
Unfortunately, no studies have been done to confirm whether these two decongestants are equally effective. There are some differences in the way the drugs are absorbed by the body:
The intestines will absorb only about 38% of the amount of phenylephrine in one tablet, while pseudoephedrine is 100% absorbed.
The effects of phenylephrine do not last as long as pseudoephedrine. Therefore, phenylephrine needs to be taken every four hours, while pseudoephedrine can be taken every four to six hours.
On another note, I don't mind "coughing up" my drivers license, it is the exorbitant price that gets me. Pseudoephedrine used to be so inexpensive, and now even for the off brand it's anywhere from $1-$3 PER PILL! My doc put me on Allegra D for chronic sinusitis and migraine control, and $45 a month for an OTC med is just insane. I'll give you my drivers license, birth certificate, divorce decree, marriage certificate, SS #, even a DNA sample EVERY TIME, just drop the price to where it's a manageable amout for people.
winkie_pinkie
21 Sep 2017
I bought Kroger brand pseudoephedrine from behind the pharmacy counter and it wasn't anywhere near $1 per pill! A 48 pack was about $12, so closer to $0.25 a pill?
maevian31
9 Feb 2012
When you try taking one and then the other you can usually feel a difference right away. My favourite cold formula contains pseudoephedrine and it brings a huge relief (you can really feel it starting to work) to my runny nose + watery, itchy eyes. It does make my mouth dry a bit too much, but I can go to work without sneezing all over my colleagues and customers.
I was tempted to try phenylephrine of course, but then one capsule didn't do anything. I tried to pair it with an antihistamine - again, it only stopped the sneezing and I had hard time at work. Pseudoephedrine wins and it's sad to see it disappear.
CaseyBear
26 May 2012
Maevian, I am not a medical professional, but it seems to me you are describing the effects of an ANTIHISTAMINE, rather then the effects of the DECONGESTANTS phenylephrine and pseudoephedrine. Antihistamines relieve sneezing and itchy, watery eyes. Decongestants help relieve congestion in the nasal passages and make breathing easier. I suspect you are using combination products which contain different ingredients besides that of the decongestant.
bluejeni
8 Dec 2013
2 10mg phenylephrine hci at bedtime works great for me as a preventive for waking up with a sore throat due to drainage.
I cannot take pseudoephedrine, even 15mg makes me want to climb the wall...
aicohn
4 Feb 2012
Pseudoephedrine works, phenylephrine is no better than placebo. Found that out with a web search after suffering through a sleepless night with a badly congested head & vastly exceeding recommended dose for phenylephrine.
FDA is willfully incompetent as usual in maintaining the charade oral phenylephrine does anything at all. It's inactivated my MAO inhibitors in the stomach & does nothing. If you want relief of your congestion, bite the bullet, cough up your drivers license & get the pseudoephedrine from behind the counter.
Signed an MD.
cosmowgirl
5 April 2013
Thank you for that answer, I live in Mississippi where we can no longer get pseudoephedrine without a prescription, which means I have to go to the doctor and spend $90 to see the doctor just to get a prescription for Sudafed. Normally, as much as I work, and don't have time to go to the doctor for a minor cold, I would go to the pharmacy and get a box of Sudafed and it would help my symptoms until the virus was gone. NOW, I go to the doctor when I am absolutely incapacitated, I'm driving with104 fever, mind you, and am usually diagnosed with walking phenomena by the time it gets bad enough for me to go to the doctor. Which is more apprehensive? Having a minor cold and driving 6 hours to get an over the counter drug that works, or having to go the doctor by the time you can't function and getting antibiotic shots, dodecahedron shots, and an oral antibiotic as well as cough meds? I spend more now that I ever did when I could control my own symptoms!
aicohn
6 April 2013
I'm sorry for you. The only reason for controlling pseudoephedrine is that it can be & is used to synthesize MDMA (known as "ecstasy"). In Texas, you have to get it from behind the pharmacist's counter & cough up a driver's license. And I suppose if you go from pharmacy to pharmacy hoarding pseudoephedrine, you may get a knock on the door. MDMA can be syntehsized from other things also (as a college student many moons ago --- statute of limitations long since run!) I used to do it from piperonal (my grades in organic chemistry were "A" and "A+" which helped with med school admissions. But it seems to me the whole thing is a ridiculous throwback to the days of the "reefer madness" movies. I don't know what to suggest other than moving to a more reasonable state. I know how I feel with a head cold, and how I get. Nose spray has substantial downsides, like rebound. But I'm afraid that little else taken orally really works at all.
AMothersDaughter
15 April 2013
Just to respond to aicohn above: the drug that can be made from Sudafed is not MDMA (ecstasy) but methamphetamine (crystal meth). I'm happy to submit my drivers license for real pseudoephedrine because it works & I'd hate to see it taken off the market!
dwsimy
3 May 2015
MY VA provider decided to take me off the medication that worked well when taken with the cetirizine, that I was already taking. I asked for pseudoephedrine, which she wrote take one every six hours. Only once did I take more than one a day, and found out one was enough. I told her that two weeks ago.
People with agendas should keep them to themselves, and being in the
health care field is the wrong place to manipulate people because some low life decided to play cook with chemicals, NOT MY PROBLEM.
thisonelow
16 Feb 2017
Cant be used... easily or cost effectively, to produce MDMA. Thats insane. The reagents alone would cost more let alone the time.
mitjason
13 Jan 2010
Pharmacists Leslie Hendeles and Randy Hatton of the University of Florida suggested in 2006 that oral phenylephrine is ineffective as a decongestant at the 10-mg dose used, arguing that the studies used for the regulatory approval of the drug in the United States in 1976 were inadequate to prove effectiveness at the 10-mg dose and safety at higher doses. Other pharmacists have expressed concerns over phenylephrine's effectiveness as a nasal decongestant, and other clinicians have indicated concern for regulatory actions that reduced the availability of pseudoephedrine.
A subsequent meta-analysis by the same researchers concluded that there is insufficient evidence for its effectiveness, though another meta-analysis published shortly thereafter by researchers from GlaxoSmithKline found the standard 10 mg dose to be significantly more effective than a placebo.Additionally, two studies published in 2009 examined the effects of phenylephrine on symptoms of allergic rhinitis by exposing sufferers to pollen in a controlled, indoor environment. Neither study was able to distinguish between the effects of phenylephrine or a placebo. Pseudoephedrine and loratadine-montelukast therapy were found to be significantly more effective than both phenylephrine and placebo.
The Food and Drug Administration has stood by its 1976 approval of phenylephrine for nasal congestion as the debate continues.
So basically they changed to formulation of Pseudoephedrine to Phenylephrine because Phenylephrine can't be used in producing Methamphetamine. I personally think that Pseudoephedrine is a much better drug but it's limited depending on where you live in the country. In Utah everything that has Pseudoephedrine in it has to be purchased through the pharmacy and you can only get so much of it. This is to prevent to making of Methamphetamine which I think is ridiculous. I hope this answers your question! Good Luck!
ceadill
3 April 2011
the manufacturing of methamphetamine is relocated mainly in mexico now so i think they should give us more freedom with the one that realy works
Nick Novicky
1 Sep 2014
I was very sick on my trip to Philippines in 2014, I went to Watson pharmacy over there, and Pharmacist give me 10 tablets of Neozep's Phenylphrine.HCl 10 mg with paracetamol 500 mg... The product work as CHARM... I was OK after using only 3 tablets... Your findings is very inaccurate and politically motivated... Nick Novicky
Grant Strachan
27 Nov 2014
Nick's comment is anecdotal and therefore irrelevant due to the obvious patient bias.
Statik2083
14 Jan 2015
As to Nicky's comment
1) "I was sick" does not describe your conditions or why you where given phenylephrine.
2) "Sick" is definitely not "allergic rhinitis" which is the primary condition most people who regularly take drugs like Loratadine-Pseudoephedrine (i.e. Claritin D) or any other second generation allergy drug with the -d
3) you make no actual comparison or site any data that compares Pseudophedrine to phenylephrine.
I could equally point out how Loratadine-Pseudoephedrine treated my allergy issues quite well in the 90s. I eventually weaned off of it to using Loratadine, Cetirizine and most recently Fexofenadine.
After a particularly nasty bout of aggravated allergic rhinitis (to the point where I thought I'd had a cold for a month) I switched to Fexofenadine-Pseudophedrine and my symptoms immediately ceased.
Incidentally when I was treating it as a cold I consumed a generic version of Nyquil, which reading the bottle used Phenylephrine rather than Pseudoephedrine. It did not do anything for the primary symptoms (Congestion with Post-nasal drip and irritation caused by post-nasal drip)
Again, my views are entirely anecdotal and quite possibly biased, I am neither a doctor nor any form of clinician, I'm simply some poor guy who regularly suffers from rhinitis and sinusitis caused by allergies.
The OP at least gives studies and information to back up his critique with hard data.
thisonelow
16 Feb 2017
Nick Novicky... truly anectodal and potentially placebo. Phenylephrine, more properly known as para-hydroxyephedrine, is a metabolite of pseudoephedrine. The primary metabolite. So, to out body, it is at best, second best.
Related topics
phenylephrine, pseudoephedrine
Further information
Similar questions
Search for questions
Still looking for answers? Try searching for what you seek or ask your own question.
