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pamela_hart2026-04-18

I've been dealing with some really bad diarrhea, and I was prescribed Loperamide/simethicone 2-125mg Tabs. The doctor said it would help with the cramps and gas. I took my first dose about an hour ago, and I'm feeling a bit lightheaded and sleepy. Is this normal? Before this happened I was not taking any other medications. I'm a little worried because I have to drive to work tomorrow. Are these side effects I should be concerned about? And if so, how long do they last? This is my first time taking this med, so any advice would be helpful.

1 min read
last active 4/18/2026
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Comments (10)

J
joyce_murray4/17/2026

I've had severe allergic reactions in the past, and with any med it's best to take the first dose when you won't need to drive, so you can see how it affects you. A lot of people get sleepy and dizzy the first time. So if you can, take the next dose when you know you can rest.

N
nancy_herrera4/17/2026

I've had this before, and it definitely made me feel tired. I just made sure to stay hydrated and avoid driving until I knew how it affected me. Also, if you feel like you have to run to the bathroom, don't hold it in.

P
priya_sharma4/17/2026

I've taken this before and felt a bit tired, but it went away after a few hours. Just make sure to stay hydrated and avoid driving if you feel too drowsy. If you get any allergic reactions like swelling in the face or trouble breathing then definitely seek help.

T
timothy_thompson4/17/2026

I had a similar experience. The dizziness and fatigue lasted about 3-4 hours for me. Took another after that and I was mostly fine with no diarhea. Also it made me constipated but that was ok because of the diarrhea. I would also just try to rest and see if it goes away. If it persists, contact your doctor.

R
ralph_andrews4/17/2026

Why didn't you ask the pharmacist about side effects when you picked up the prescription?

H
hannah_washington4/17/2026

I've had similar side effects with some meds. If it gets worse or persists, it might be worth calling your doctor just to be safe, especially since you have to drive.

M
martha_fox4/17/2026

Feeling lightheaded and sleepy is not uncommon with this med.

K
kathryn_peters4/17/2026

I'm not sure how long it takes for the side effects to subside; I never experienced them, but didn’t you get instructions on when to take it and what to expect?

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teresa_henry4/17/2026

This reminder has me wanting to look at the side effects page for all my meds.

J
judy_berry4/17/2026

Make sure to drink plenty of fluids and eat light, bland foods to help your body adjust. Avoid heavy meals or alcohol, and if the side effects worsen or you experience any severe symptoms, go to the ER.