Is Histex DM Safe To Take If You Have High Blood Pressure?

In our latest question and answer, our pharmacist discusses whether or not Histex DM is safe if you have high blood pressure.


If high blood pressure is under control, is it okay to take Histex DM cough medicine in 5ml doses every 4 hours?

Asked by TMAC On Jan 04, 2023

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Jan 05, 2023
Last updated Jan 05, 2023

Key points

  • Histex-DM contains a nasal decongestant, phenylephrine. Nasal decongestants are recommended to be used with caution in those diagnosed with high blood pressure.
  • Studies show that oral decongestants likely only increase blood pressure to a minor degree for most individuals, but longer-term studies are needed.
  • In those with well-controlled blood pressure and minimal cardiovascular risk factors, nasal decongestants are generally safe to use in the short-term, but you should speak to your doctor for specific guidance.


Thanks so much for reaching out. I'm happy to answer this for you.

First and foremost, let's list the ingredients contained in Histex-DM:

  • Dextromethorphan
  • Triprolidine
  • Phenylephrine

Dextromethorphan is a cough suppressant, triprolidine is an antihistamine and phenylephrine is a nasal decongestant.


Safe With High Blood Pressure?

In general, any medication that contains a nasal decongestant, like phenylephrine, is going to have a precaution for those who have high blood pressure or take high blood pressure medication.

This is because nasal decongestants are associated with causing small increases in blood pressure, which could put some individuals more at risk for negative outcomes.

Now, it must be said that research is quite conflicting on just how much nasal decongestants can increase blood pressure.

Some studies report that phenylephrine, at usual doses, does not increase blood pressure:

Phenylephrine showed no consistent effect on heart rate or blood pressure for doses of 25 mg or less
Ann Pharmacother . 2007 Mar;41(3):381-90

However, other studies have noted that phenylephrine may be a culprit in some case reports documenting individuals experiencing high blood pressure after taking the medication.

The consensus on the matter is that oral decongestants, like phenylephrine, could potentially increase blood pressure, but not for everyone, and generally only to a mild degree (one study noted an average increase of 1.2mmHg with a similar decongestant, pseudoephedrine).

However, and this is an important point, there aren't any long-term studies that have evaluated the safety of nasal decongestants in someone who has blood pressure, so we don't have long-term outcomes data.


I recommend talking to your doctor regarding whether or not a medication that contains a nasal decongestant is right for you, as everyone's medical situation is different.

In my experience, if someone has been diagnosed with high blood pressure, and it is controlled, and they don't have other risk factors (such as a prior heart attack), the short-term use of a nasal decongestant is generally safe.

However, as mentioned, I recommend talking to your doctor so they can provide specific guidance for you.

Final Words

Thanks for reaching out Please do so again anytime.


  • Histex-DM Monograph, PubMed
  • Efficacy and safety of oral phenylephrine: systematic review and meta-analysis, PubMed
  • Potential cardiovascular adverse events when phenylephrine is combined with paracetamol: simulation and narrative review, PubMed
  • Cold medication containing oral phenylephrine as a cause of hypertension in children, PubMed
  • Are oral decongestants safe in hypertension? An evaluation of the evidence and a framework for assessing clinical trials, PubMed
  • Clinical Inquiry: Do oral decongestants have a clinically significant effect on BP in patients with hypertension?, PubMed

About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at! You can also connect with Dr. Brian Staiger on LinkedIn.

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