Why is Ampicillin prescribed?
Ampicillin is a penicillin-like antibiotic prescribed for a wide variety of infections, including gonorrhea and other genital and urinary infections, respiratory infections, and gastrointestinal infections, as well as meningitis (inflamed membranes of the spinal cord or brain).
Most important fact about Ampicillin
If you are allergic to either penicillin or cephalosporin antibiotics in any form, consult your doctor before taking ampicillin. There is a possibility that you are allergic to both types of medication; and if a reaction occurs, it could be extremely severe. If you take the drug and develop a skin reaction, diarrhea, shortness of breath, wheezing, sore throat, or fever, seek medical attention immediately.
How should you take Ampicillin?
Take ampicillin capsules with a full glass of water, a half hour before or 2 hours after a meal.
The oral suspension should be shaken well before using.
Take Ampicillin exactly as prescribed. It works best when there is a constant amount in the body. Take your doses at evenly spaced times around the clock, and try not to miss a dose.
--If you miss a dose...
Take it as soon as you remember. If it is almost time for the next dose, and you take 2 doses a day, take the one you missed and the next dose 5 to 6 hours later. If you take 3 or more doses a day, take the one you missed and the next dose 2 to 4 hours later. Then go back to your regular schedule. Do not take 2 doses at once.
--Storage instructions...
Store capsules at room temperature in a tightly closed container.
Keep the oral suspension in the refrigerator, in a tightly closed container. Discard the unused portion after 14 days.
What side effects may occur?
Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine whether it is safe for you to continue taking Ampicillin.
• More common side effects may include:
Colitis (inflammation of the bowel), diarrhea, fever, itching, nausea, rash or other skin problems, sore tongue or mouth, vomiting

Why should Ampicillin not be prescribed?
You should not take ampicillin if you are allergic to penicillin or cephalosporin antibiotics.
Special warnings about Ampicillin
If you have an allergic reaction, stop taking Ampicillin and contact your doctor immediately.
After you have taken ampicillin for a long time, you may get a new infection (called a superinfection) due to an organism Ampicillin cannot treat. Consult your doctor if your symptoms do not improve or seem to get worse.
Ampicillin sometimes causes diarrhea. Some diarrhea medications can make the diarrhea worse. Check with your doctor before taking any diarrhea remedy.
Oral contraceptives may not work properly while you are taking ampicillin. For greater certainty, use other measures while taking Ampicillin.
If you are diabetic, be aware that ampicillin may cause a false positive in certain urine glucose tests. You should talk to your doctor about the right tests to use while you are taking ampicillin.
For infections such as strep throat, it is important to take ampicillin for the entire amount of time your doctor has prescribed. Even if you feel better, you need to continue taking the medication.
Possible food and drug interactions when taking Ampicillin
If ampicillin is taken with certain other drugs the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining ampicillin with any of the following:

Allopurinol (Zyloprim)
Atenolol (Tenormin)
Chloroquine (Aralen)
Mefloquine (Lariam)
Oral contraceptives
Special information if you are pregnant or breastfeeding
The effects of ampicillin during pregnancy have not been adequately studied. If you are pregnant or plan to become pregnant, inform your doctor immediately. Ampicillin should be used during pregnancy only if the potential benefit justifies the potential risk to the developing baby.
Ampicillin appears in breast milk and could affect a nursing infant. If Ampicillin is essential to your health, your doctor may advise you to stop breastfeeding until your treatment is finished.
Recommended dosage
Unless you are being treated for gonorrhea, your doctor will have you continue to take ampicillin for 2 to 3 days after your symptoms have disappeared. Dosages are for capsules and oral suspension.
ADULTS
Infections of the Genital, Urinary, or Gastrointestinal Tracts
The usual dose is 500 milligrams, taken every 6 hours.
Gonorrhea
The usual dose is 3.5 grams in a single oral dose along with 1 gram of probenecid
Respiratory Tract Infections
The usual dose is 250 milligrams, taken every 6 hours.
CHILDREN
Children weighing over 44 pounds should follow the adult dose schedule.
Children weighing 44 pounds or less should have their dosage determined by their weight.
Infections of the Genital, Urinary, or Gastrointestinal Tracts
The usual dose is 100 milligrams for each 2.2 pounds of body weight daily, divided into 4 doses for the capsules, and 3 to 4 doses for the suspension.
Respiratory Tract Infections
The usual dose is 50 milligrams for each 2.2 pounds of body weight daily, divided into 3 to 4 doses.
Overdosage
Although no specific symptoms have been reported, any medication taken in excess can have serious consequences. If you suspect an overdose of ampicillin, seek medical attention immediately.