Cefdinir, also known by its brand name Omnicef, is a cephalosporin antibiotic that can treat several types of bacterial infections, such as pneumonia, sinus infections, and ear infections. Although the brand name is no longer available, its generic can still be prescribed for adults and children. Cefdinir comes as capsules and a suspension that are taken once or twice per day by mouth. Side effects can include diarrhea, nausea, and rash.
Lung infections related to long-term bronchitis
Skin infections
Ear infections - for children only
Cefdinir is a cephalosporin antibiotic. It kills bacteria by preventing them from making an additional covering around themselves for protection.
Source: DailyMed
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
Rare
Black, tarry stools
chills
painful or difficult urination
shortness of breath
sores, ulcers, or white spots on the lips or in the mouth
swollen glands
unusual bleeding or bruising
unusual tiredness or weakness
Incidence not known
Abdominal or stomach cramps or tenderness
back, leg, or stomach pains
bleeding gums
blistering, peeling, or loosening of the skin
blood in the urine or stools
bloody nose
bloody or cloudy urine
bloody, black, or tarry stools
blue lips, fingernails, or skin
bruising
chest pain or discomfort
clay-colored stools
cold, clammy skin
confusion
coughing or vomiting blood
cracks in the skin
dark-colored urine
diarrhea, watery and severe, which may also be bloody
difficult or troubled breathing
difficulty with breathing or swallowing
dilated neck veins
dizziness
extreme fatigue
fast heartbeat
fast, weak pulse
feeling of discomfort
general body swelling
general tiredness and weakness
headache
heavier menstrual periods
high fever
hoarseness
increased thirst
inflammation of the joints
irregular breathing
irregular heartbeat
irregular, fast or slow, or shallow breathing
joint or muscle pain
light-colored stools
lightheadedness
loss of appetite
loss of consciousness
loss of heat from the body
muscle aches
muscle cramps or spasms
muscle pain or stiffness
nausea or vomiting
noisy breathing
nosebleeds
pain in the ankles or knees
pain or discomfort in the arms, jaw, back, or neck
painful, red lumps under the skin, mostly on the legs
pale skin
persistent bleeding or oozing from puncture sites, mouth, or nose
pinpoint red spots on the skin
problems with bleeding or clotting
puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
rash
red skin lesions, often with a purple center
red, irritated eyes
red, swollen skin
seizures
severe stomach pain
slow or irregular breathing
sudden decrease in the amount of urine
sweating
swelling of the face, fingers, feet, or lower legs
swollen lymph glands
tightness in the chest
unpleasant breath odor
unusual weight loss
upper right abdominal or stomach pain
vomiting of blood
yellow eyes or skin
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:
Less common
Itching of the vagina or genital area
pain during sexual intercourse
thick, white vaginal discharge with no odor or with a mild odor
vaginal yeast infection
Rare
Acid or sour stomach
belching
excess air or gas in the stomach or intestines
full feeling
increase in body movements
increased clear or white vaginal discharge
indigestion
lack or loss of strength
passing gas
rash with flat lesions or small raised lesions on the skin
sleepiness or unusual drowsiness
soreness or redness around the fingernails and toenails
stomach discomfort, upset, or pain
unable to sleep
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.
Available as a capsule and oral suspension
Can be used for children and adults
Might be able to take once per day, depending on the infection
Can keep oral suspension at room temperature for up to 10 days
Might not be able to take this antibiotic if you've had a severe allergic reaction to penicillins or other cephalosporin antibiotics
Must separate when you take cefdinir and antacids or iron supplements by at least 2 hours
Oral suspension contains sugar, so people with diabetes might have higher blood sugar levels while they're taking the antibiotic
Not recommended for the cold or flu, since they're not caused by a bacterial infection
Take cefdinir exactly as your healthcare professional (HCP) instructed you to. It's important to finish your treatment course, even if you start feeling better. Stopping the medication earlier than prescribed can make your infection come back and become harder to treat.
You can take cefdinir with or without food. But if the antibiotic upsets your stomach, try taking it with food to help.
Make sure to tell your HCP and pharmacist about all of the medications, over-the-counter products, and supplements you're taking. They can let you know if you need to take any of them, like antacids and iron supplements, at a different time than cefdinir to avoid drug interactions.
Ask your HCP whether it's safe and appropriate for you to take a probiotic to help lessen the risk of rare, but serious infectious diarrhea. If your HCP recommends taking a probiotic, take it at least 2 hours before or after cefdinir to prevent the antibiotic from killing the "good" bacteria in the probiotic.
Get medical care right away if you have watery or bloody diarrhea, fever, fatigue, or stomach cramps anytime while you're taking cefdinir or after you finish your antibiotics. These could be signs of serious infectious diarrhea that should be treated right away.
Contact your HCP or get medical help as soon as possible if you have a rash, itchy skin, trouble breathing, or swelling in your face or mouth. These could be signs of a severe allergic reaction.
For the cefdinir capsules:
Swallow the cefdinir capsules whole with water; don't crush or chew them. Ask your HCP about other options, such as switching to the oral suspension formulation, if you're having trouble swallowing the capsules whole.
Store the cefdinir capsules in a cool and dry place at room temperature and away from light.
For the cefdinir oral suspension (liquid):
Shake the cefdinir bottle well before each time you measure out the medication. Make sure to only use a medication dose cup or oral syringe from the pharmacy to measure out your dose. Don't use household spoons; they aren't accurate and using them might cause you to take the wrong dose.
Store the cefdinir suspension at room temperature for up to 10 days. After 10 days, throw away the bottle, even if there's still some medication left.
Cefdinir can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Allergy to penicillin or other cephalosporin antibiotics
Severe allergic reactions to cefdinir are possible, including life-threatening reactions like facial swelling, shock, and anaphylaxis (closing of the throat). Let your prescriber know if you have an allergy to antibiotics so they can check for your risk of having an allergic reaction to cefdinir. Get medical attention right away if you notice hives, rash, red skin, swelling of the lips or tongue, or difficulty breathing after you take cefdinir.
Antibiotics, including cefdinir, raise your risk of getting infected with a bacteria called Clostridioides difficile (C. diff). Antibiotics change the amount of normal bacteria in your stomach and intestines. This can allow C. diff to overgrow in your gut and lead to an infection. This infection can cause diarrhea that can sometimes be life-threatening.
It's important to recognize the difference between diarrhea as a side effect of cefdinir and this type of infectious diarrhea. C. diff-related diarrhea can cause rapid heart rate, foul-smelling diarrhea, fever, nausea, frequent bowel movements (even up to 15 times per day) and is a medical emergency. Get medical help right away if you have any of these symptoms so you can get tested for C. diff infection and get appropriate treatment, if needed.
Take cefdinir exactly as prescribed. Using cefdinir for any shorter or longer periods of time or taking the antibiotic for other illnesses can raise your risk for developing infections caused by drug-resistant bacteria. These types of infections can be severe, life-threatening, and more difficult to treat.
Ages 13 years and older (capsules only):
The typical dose is 300 mg by mouth every 12 hours for 5 to 10 days.
For certain infections (sinus infections, strep throat, tonsil infections, and infections related to bronchitis), you might be able to take 600 mg once per day for 10 days.
Ages 6 months to under 13 years (oral suspension only):
The dose is based on your child's body weight. The typical dose is 7 mg/kg of body weight by mouth every 12 hours for 5 to 10 days.
For certain infections (ear infections, sinus infections, strep throat, and tonsil infections), your child might be able to take a higher dose (14 mg/kg) once per day for 10 days.
Your dose might differ if you have kidney problems.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Severe allergy to cephalosporin antibiotics
Lung infections related to long-term bronchitis
Skin infections
Ear infections - for children only
Lung infection related to long-term bronchitis
Skin infection
UTI
Skin infection
Bone and joint infection
Lung infection related to long-term bronchitis
Skin infection
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Aurobindo Pharma Limited. (2024). Cefdinir powder, for suspension [package insert]. DailyMed.
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MedlinePlus. (2024). Chronic bronchitis.
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