Joe asked
Hello. I took lactulose at 6pm. May I take Zzzquil tonight at 11pm? Thanks for your answer!!
Answer
There are no drug interactions between lactulose and Zzzquil
(diphenhydramine). However, lactulose can decrease the absorption of some drugs due to
the rapid increase in gut motility. In other words, it increases the speed at which drugs and food move through your GI tract. Examples of these medications include
hydrocodone and fosfomycin. There is no
evidence to suggest diphenhydramine absorption is affected by lactulose. Read
more about both lactulose and diphenhydramine below.
Information About Lactulose
Lactulose
is FDA approved for the treatment of constipation and hepatic encephalopathy, a
mental condition resulting from liver damage. Lactulose was first approved by
the FDA in 1976.
For treatment of constipation, lactulose is typically dosed
at 15 to 30 mL once daily and can be increased up to 60 mL once daily. Response
varies, but generally begins to work within 24 to 48 hours. Dosing can vary
based on the reason for being prescribed the medication.
For the treatment of hepatic encephalopathy, dosing is more
frequent at 30 to 45 mL up to 4 times daily. Many times, lactulose dosing and
frequency is adjusted based on the number of soft stools per day. Lactulose
works to improve the mental status in patients with hepatic encephalopathy by
reducing blood ammonia levels.
Information About Diphenhydramine
Diphenhydramine (Benadryl)
is a first-generation antihistamine. Antihistamines are widely used for
self-care of allergy symptoms including runny nose, watery eyes, sneezing, and
itching of the nose, throat, or eyes. Benadryl may also be used for symptoms of
the common cold, allergic reactions, occasional insomnia, and more.
Because Benadryl is a first-generation antihistamine, it is
more likely to cause sedation and drowsiness. Other first-generation
antihistamines include Dramamine (dimenhydrinate), Chlor-Trimeton (chlorpheniramine),
Tavist (clemastine), and Phenergan (promethazine), among others.
These medications cross the blood-brain barrier and have CNS effects like drowsiness and dizziness. First generation antihistamines can also cause urinary retention, GI upset, and blurry vision.
The first generation antihistamines are also listed as medications to
avoid in elderly adults by the Beers Criteria
due to the increased risk of confusion, dry mouth, and drowsiness.
Second generation antihistamines include Claritin (loratadine), Cetirizine (Zyrtec), and Allegra (fexofenadine) and are much less sedating. These antihistamines are generally only used for treatment of allergy symptoms, whereas Benadryl can be used for a variety of reasons including allergies, insect bites, poison ivy, sleep, and motion sickness.
