How Long Before Bedtime Can I Take Sudafed?

In our latest question and answer, the pharmacist discusses how long before bedtime Sudafed (pseudoephedrine) should be taken to avoid issues with insomnia.

Question

How long before bedtime should I take my last dose of Sudafed? I am taking Sudafed for a cold/flu (Not sure which). I want to be able to sleep so I was wondering how long Sudafed keeps me awake. What is the half-life?

Asked by Richard On Sep 20, 2022

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Sep 20, 2022
Last updated Apr 18, 2024

Key points

  • Sudafed immediate-release products should be taken at least 2 hours before bedtime to avoid issues with insomnia. Certain individuals may need to take their last dose 4-6 hours before bedtime.
  • Extended-release Sudafed products should be taken t least 4 to 6 hours before bedtime to avoid issues with insomnia.

Answer

Sudafed (pseudoephedrine) is an oral nasal decongestant that is used to treat nasal congestion due to the common cold and allergies. It is also helpful in relieving congestion of the eustachian (i.e. auditory) tubes in the ears. 

It does have a mild stimulant effect and can cause insomnia, especially if taken too close to bedtime. Therefore, you want to be sure to take it long enough before bed to avoid this problem.

How Does Sudafed Work?

Sudafed works by producing vasoconstriction, shrinking swollen nasal membranes, and opening nasal passages to ease airflow. It can also facilitate the drainage of sinus secretions.

Sudafed is classified as a sympathomimetic and has mild stimulatory effects. As such, it is recommended to avoid taking it before bedtime as it can cause insomnia, trouble sleeping, and a general feeling of awakeness. Below are the commonly reported central nervous system effects:

  • Restlessness
  • Headache
  • Lightheadedness
  • Dizziness
  • Insomnia

Data indicate that both children and the elderly are more susceptible to the stimulating effects of Sudafed than adults.

There are a variety of Sudafed products available and administration recommendations vary per product. Available Sudafed products include:

  • Sudafed (Immediate Release)
  • Sudafed 12 Hour
  • Sudafed 24 Hour
  • Sudafed PE (family of products)

Sudafed Timing Before Bedtime Recommendations

Sudafed (Pseudoephedrine) Immediate Release Products

Studies show that after taking immediate-release Sudafed products by mouth, the effects begin within 30 minutes. The duration of action can vary depending on the person but generally lasts around four to six hours. The half-life of Sudafed is reported to be anywhere from 9-16 hours but can vary.

Although the nasal decongestant effects of immediate-release Sudafed products can last 4-6 hours (with the half-life

being even longer), the stimulatory effects aren't expected to last that length of time. The manufacturer of Sudafed recommends that the product should be administered at least two hours before bedtime. Some patients may be more sensitive to the stimulatory effects of Sudafed. If this is the case, plan on taking Sudafed at least 6 hours before bedtime

Sudafed (Pseudoephedrine) Extended Release Products

In addition to the immediate release product, Sudafed is also available in 12 and 24 hours formulations. For both, it is recommended to take them as far away from bedtime as possible. The 24-hour formulations should be taken first thing in the morning. Although the nasal decongestant effects will last about one day, the stimulatory effects should subside (if they occur at all), within a few hours. 

The 12 hours product should generally not be dosed within four to six hours of bedtime. Like the 24-hour products, the stimulatory effects shouldn't be an issue if spaced far enough from the time you go to bed.

Sudafed PE (Phenylephrine) Products

Sudafed PE products do not contain the active ingredient pseudoephedrine. They contain phenylephrine, which typically is associated with less stimulatory effects in users. However, the same recommendation is in place in regard to administration. Separate from bedtime by at least 2 hours for immediate-release products and longer for extended-release products.

Final Words

To summarize, the following recommendations should be considered when dosing Sudafed in regard to insomnia concerns:

  • Per the manufacturer, dose Sudafed immediate-release products at least 2 hours before bedtime to avoid issues with insomnia. Certain individuals may need to take their last dose 4-6 hours before bedtime.
  • Dose extended-release products at least 4 to 6 hours before bedtime to avoid issues with insomnia.

References

  • Pseudoephedrine Monograph, PubChem
  • Pseudoephedrine—Benefits and Risks, 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 [email protected]! You can also connect with Dr. Brian Staiger on LinkedIn.

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