Adverse Effects of Co-trimoxazole (SMZ-TMP)

Q: Hello, I am a 28 year old female who was put on an antibiotic, SMZ-TMP DS, on the 24th. I started taking it on the 25th and began having flu like symptoms. I had severe headaches, neck stiffness, uncontrollable tremors, joint pain, muscle weakness, pain, dizziness, dark pink eyes, loss of appetite, and unusual fatigue. I thought I was really sick but the second day same thing happened. I realized it was the antibiotic, so I stopped taking it. I had the same symptoms for 3 days after that.

I figured I needed to let the medicine flush out of my system. It has been 5 days and it seems like the headache is returning primarily in my temporal and occipital regions. The neck stiffness is worse; it never truly went away, but today it is really bothering me. Also, the joint aches are back.

I’m pretty certain I am allergic to the medication, so could it still be in my system? Should I go to the hospital? I need help please. Thank you in advance.
– By Beatrice


Looks like an adverse reactions to the drug.

The reaction is pretty severe. We would suggest you to visit the hospital at the earliest. Symptoms like neck stiffness make it essential to rule out meningitis. You may need to take some medical help to overcome the reaction.

You need to keep a close watch on your symptoms. If you see anything serious (life threatening) go to the ER immediately.

Nothing can be precisely said about the time the reaction will take to wane off.

The drug is eliminated via the kidney. It may take 3-5 days to get flushed out. However, the reaction, once triggered, may still persist. It may even take 15 days to go.

Take Care,

Buddy M.D.

Medical Advice (Q&As) on “A Case of Side Effects of Trimethoprim Sulfamethoxazole

    1. Buddy M.D. Post author

      It is difficult to quantify the exat dose. This largely depends upon the individual taking the medication, his previous cardiac status.

      However, commonly, such effects are seen when the patient takes the drug for long durations, 3 years or more. A regular ECG testing is recommended.

  1. Preet

    Hi, I have eye floater and sometime I get some frickle in eye and after this I get severe sharp pain in other side of brain, I also have buzzing in ear for several year.

    1. Buddy M.D. Post author

      You need to visit an ophthalmologist for examination. It is quite likely that the small muscles inside your eyes are weak and need some strengthening exercises.


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