The only F I can think of is Flagyl also known as Metronidazole. Here are the side effects, lethargy isn't mentioned.
What are the possible side effects of metronidazole?
If you experience any of the following serious side effects, stop taking metronidazole and seek emergency medical attention:
an allergic reaction (swelling of your lips, tongue, or face; shortness of breath; closing of your throat; or hives);
seizures;
numbness or tingling;
dizziness or loss of coordination; or
severe diarrhea.
Other, less serious side effects may be more likely to occur. Continue to take metronidazole and talk to your doctor if you experience
darkening of your urine;
nausea, vomiting, or loss of appetite;
an unpleasant metallic taste in your mouth;
constipation or mild diarrhea;
headache; or
swollen or sore tongue.
Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome. |