Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
More common
Black, tarry stools
blistering, peeling, or loosening of the skin
changes in skin color
chest pain
chills
cough or hoarseness
dark urine
diarrhea
dizziness
fever
general feeling of tiredness or weakness
headache
itching
joint or muscle pain
light-colored stools
loss of appetite
lower back or side pain
nausea
pain, tenderness, or swelling of the foot or leg
painful or difficult urination
pale skin
rash
red skin lesions, often with a purple center
red, irritated eyes
sore throat
sores, ulcers, or white spots in the mouth or on the lips
stomach pain
swollen or painful glands
tightness in the chest
trouble breathing
unpleasant breath odor
unusual bleeding or bruising
vomiting of blood
yellow eyes or skin
Incidence not known
Back, leg, or stomach pains
bleeding gums
blindness or vision changes
blisters, hives, or itching
bloating
blood in the urine or stools
bluish-colored lips, fingernails, or palms
burning, crawling, itching, numbness, painful, prickling, "pins and needles", or tingling feelings
burning of the face or mouth
cloudy urine
confusion
constipation
continuing ringing or buzzing or other unexplained noise in the ears
convulsions
cracks in the skin
decreased frequency or amount of urine
difficulty with swallowing
fainting spells
general body swelling
general feeling of discomfort or illness
hair loss
hearing loss
increased thirst
indigestion
irregular heartbeat
large, flat, blue, or purplish patches in the skin
large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
loss of heat from the body
muscle or joint pain
nosebleeds
not able to pass urine
numbness or tingling in the hands, feet, or lips
pain or burning while urinating
pinpoint red spots on the skin
puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
raised red swellings on the skin, the buttocks, legs, or ankles
redness of the white part of the eyes
redness, swelling, or soreness of the tongue
soreness of the muscles
stiff neck or back
stomach tenderness
swelling of the face, hands, legs, and feet
unsteadiness, trembling, or other problems with muscle control or coordination
weakness in the hands or feet
weakness or heaviness of the legs
weight gain or loss
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
Passing of gas
Incidence not known
Discouragement
feeling of constant movement of self or surroundings
feeling sad or empty
increased sensitivity of the skin to sunlight
lack of feeling or emotion
loss of interest or pleasure
nervousness
redness or other discoloration of the skin
seeing, hearing, or feeling things that are not there
sensation of spinning
severe sunburn
trouble concentrating
trouble sleeping
uncaring
weight loss
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
 Bactrim DS side effects (more detail)
