What Ampicillin Is

Ampicillin is a basic broad-spectrum antibiotic of the penicillin group. It is used for treatment and prevention of a range of bacterial infections such as respiratory infections (sinusitis, pharyngitis, bronchitis, pneumonia), genitor-urinary tract infections, STDs (gonorrhea), gastrointestinal infections (salmonellosis), endocarditis, meningitis, infection of the middle ear, whooping cough. It is also sometimes used to prevent infections in patients with a history of rheumatic heart disease or those who are undergoing invasive procedures, like dental interventions, C-sections, vaginal hysterectomies. It can also help with prevention of a streptococcal infection of group B in newborns. The drug can also be used for other purposes that are not listed in this guide.

Ampicillin is defined by the WHO as a critically important drug for human medicine and is on their list of essential medicines.

Recommendations for Use, Dosage and Overdose

Ampicillin can be administered orally in pills or suspension, as an intramuscular injection (shot) or by intravenous infusion. However, oral administration is the most common. Follow all the instructions on your prescription and the drug label and read carefully all the instruction sheets or medication guides. Use the drug exactly as prescribed.

When taking ampicillin as a pill, swallow it whole with a full glass of water. If you take the drug in a liquid form, shake the bottle before measuring a dose. Use a special dosing syringe, cup or spoon. Do not use a regular kitchen spoon. Ampicillin is usually taken on an empty stomach, at least 30 minutes before a meal. Otherwise, you will have to wait for at least 2 hours after it.

When treating STDs, it is essential to treat both the patient and their sexual partner to prevent reinfection.  When using the drug for a long term, it is advised to monitor the kidney and liver functioning, as well as blood cells levels. Use the drug for the full prescribed course, even if the symptoms improve. Skipping doses or prematurely discontinuing the treatment increases the risk of developing antibiotic-resistant infections.

Ampicillin can interfere with the results of certain medical tests. Tell your doctor if you are taking ampicillin. If you accidentally miss a dose, take it as soon as you remember but skip it if it is almost time for your next one. Do not take two doses at a time! Ampicillin overdose can lead to confusion, behavioral changes, blackouts, and convulsions, as well as electrolyte imbalance, neuromuscular hypersensitivity, and kidney failure. In case of overdosing, seek urgent medical help.

Precautions and Contraindications

Ampicillin is not intended for patients with hypersensitivity or allergy to penicillins, as they are at risk of fatal anaphylactic reactions. Hypersensitivity can manifest itself in hives, frequent skin rashes, erythema multiforme, exfoliative dermatitis, and temporary decrease in both red and white blood cells. You should not use ampicillin if you are allergic to it or similar antibiotics like amoxicillin (Moxatag, Augmentin, Amoxil, etc.), nafcillin, dicloxacillin, or penicillin.

Ampicillin is not recommended for patients with concurrent mononucleosis, as over 40% of them develop a skin rash.

To avoid developing any severe side effects, tell your doctor if you have ever had:

  • Asthma;
  • Diabetes;
  • Antibiotic-associated diarrhea;
  • Hay fever (seasonal allergy);
  • Kidney or liver conditions;
  • Allergies to an antibiotic.

You should also inform your doctor if you are pregnant or breastfeeding. It is not advised to breastfeed during ampicillin use.

Interactions with Other Drugs and Substances

Large doses of ampicillin increase the risk of bleeding when used simultaneously with oral anticoagulants such as warfarin.

Other antibiotics, such as erythromycin, chloramphenicol, tetracyclines, and cephalosporins, can make ampicillin less effective. When taken simultaneously as aminoglycosides, the drugs can bind and inactivate each other. If administered separately, however, ampicillin and aminoglycosides can increase each other’s effect.

Ampicillin reacts with methotrexate and probenecid to decrease renal clearance. The combination of ampicillin and allopurinol is associated with the more common occurrence of rashes. Avoid alcohol when using ampicillin to prevent liver damage. Note that live bacterial vaccines, like live typhoid or cholera vaccine, can be made ineffective if received during ampicillin treatment. Therefore, vaccination needs to be put off until after ampicillin course is finished.

Ampicillin can make oral birth control less effective. To avoid unwanted pregnancy, use non-hormonal birth control methods (like condoms or a diaphragm with spermicide).

Other drugs, both prescription and over-the-counter medicines like vitamins and herbal products, may affect ampicillin. Inform your physician about any other drugs or substances you are using.

Side Effects

Ampicillin is generally much safer than other antibiotics. Side effects are most likely to occur only in patients who are sensitive to penicillins and who have a history of allergies or asthma. Severe side effects such as anaphylaxis, angioedema, seizures, serum sickness, and C. difficile infection are very rare. The most common side effects are diarrhea and rash (experienced by about 10% of users). Less common effects include “hairy tongue”, vomiting, nausea, itching, and blood dyscrasias. The gastrointestinal effects are more common with oral administration. Other conditions may develop up to several weeks after treatment.

Get urgent medical help if you have the symptoms of an allergic reaction (hives, short breathing, swollen lymph nodes) or severe skin reaction (sore throat, fever, rash, blistering and peeling, burning eyes).

Consult your physician in case of:

  • Severe abdominal pain, watery or bloody diarrhea;
  • Soreness in your oral cavity;
  • Rash or itching;
  • Swollen glands, fever, sore throat, chills, joint pain, fatigue;
  • Pale skin, dizziness.

This list of side effects is not complete; others effects still may occur.

Keep in Mind

Please, give your physician full and accurate information about your health, your past medical history, all the medications and substances you are taking, known allergies, pregnancy or breastfeeding. Use ampicillin only by prescription of a qualified physician and in strict accordance with the instructions! Note that ampicillin, as any other antibiotic, does not treat viral infections, like flu or common cold! Do not use it on your own or advise anyone to do so. Do not stop the treatment prematurely.

Store the drug in a dry place away from sunlight and dispose of any expired leftovers. Keep away from children. Inform your physician immediately about any severe side effects or reactions you experience.