Ampicillin is a type of medication used for the treatment of bacterial infections. This medication, like most antibiotics, is only available through prescription from a medical professional or consultant. More information

A doctor will review your order and write you a prescription, if appropriate. This prescription is then forwarded to a pharmacy. The pharmacy will have your medicine delivered to you within one to three working days. Read more about this process here.

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Patient Leaflet(s)

Ampicillin is a form of antibiotic that is designed to kill dangerous or harmful bacteria in the body. The active ingredient in this medication helps to prevent the growth of bacteria on the cell walls and stops them from reproducing.  

What is Ampicillin? 

Ampicillin is a type of medication used for the treatment of bacterial infections. This medication, like most antibiotics, is only available through prescription from a medical professional or consultant. You can be given Ampicillin to treat a range of different conditions, spreading all the way from ear infections and sinus infections, to chest problems and urine infections.  

The active ingredient of Ampicillin works to kill the bacteria or germs that are causing the infection and your symptoms. Ampicillin belongs to a class of penicillin-based antibiotics. These medications work in a very similar way to other penicillin-based drugs. Because Ampicillin kills the bacteria causing your infection, it prevents the problem from becoming worse, and helps you to rid your body of the infection.  

When is Ampicillin used? 

Ampicillin is an antibiotic medication that can be used for the treatment of a wide selection of conditions. Ampicillin is used for the treatment of bacterial infections. Those are infections of the body caused by the overabundance of bad bacteria in your system. Your doctor or consultant may give you Ampicillin if you have a chest infection, a urine infection, ear infection, or steptococcal  throat infections.  

Crucially, this medication will only work to treat infections that are caused bacteria. It will not help to eliminate viral infections like the flu or common cold. Using any kind of antibiotic when it is not needed could mean that it is less likely to work when you encounter future infections. 

Many infections are now growing more resistant to antibiotics, particularly those that use penicillin.  

How do you use Ampicillin? 

Ampicillin is often prescribed in tablet or pill form. It comes in both 250mg and 500mg dosages. You will be told how much you need to take and how often you need to use this medication by your consultant. Before you begin using Ampicillin, it is important to read the patient leaflet provided with this medication. The patient leaflet will provide you with useful information about the side-effects that this drug can cause.  

Ampicillin’s patient leaflet will also let you know if there are any people who should avoid taking Ampicillin entirely. Ampicillin is best taken on an empty stomach, which means that you will need to use it either two hours after having a meal, or one hour before your meal. You should have a full glass of water when taking this medication, and make sure that you drink plenty of fluids, as Ampicillin can cause you to feel more dehydrated.  

To get the best results from this drug, you should take it at evenly spaced times throughout the day. It may be helpful to set an alarm to remind you to take your medication at the same time each day. You should also continue to take this medication until you are finished with the full prescribed amount. Remember, you should not stop taking Ampicillin early, or your chances of the infection returning could be higher.  

If your condition persists or worsens after several days of using Ampicillin, consult your doctor to find out what you should do next.  

What dosages are there? 

Ampicillin is available in two different strengths, depending on your condition and the kind of treatment that you need, your doctor or consultant will tell you which medication you need to take. If you are taking Ampicillin for a bladder infection, for instance, you may need to take a single capsule three times a day. Alternatively, people using Ampicillin for more severe infections could be required to taker Ampicillin four times per day.  

The most common dose of Ampicillin is one capsule four times per day, taken orally. Do not use more of this medication than prescribed by your doctor. Do not continue to take Ampicillin for longer than you are told to do so. Taking more of your prescribed medication than necessary won’t get rid of your infection any quicker, but it could increase your chances of side effects.  

Although your medication will begin working immediately, you may not notice the benefits of using Ampicillin until a few days after you begin taking it.  

What are the side effects of Ampicillin? 

Ampicillin, like all medications, can sometimes cause unintended side effects alongside the effects that are intended from this substance. You should make sure that you are aware of the side effects that can be caused by Ampicillin, so you know how to deal with them.  

Common side effects of Ampicillin can include nausea, diarrhea, and vomiting. It is also possible that you might experience sores on your tongue or around your mouth. If any of these effects worsen or persist, you should contact your pharmacy or doctor.  

Speak to your doctor immediately if any more severe side effects take place, including dark or strange colored urine, persistent vomiting, or nausea. You should also seek help if you have severe abdominal pain, yellowing of the skin or eyes, easy bleeding or bruising, or a persistent fever. These symptoms could be signs of a severe internal problem.  

Ampicillin can sometimes cause a severe intestinal condition called clostridium difficile diarrhea. If this happens, it may be because of a type of very resistant bacteria. Your condition may occur while you are taking Ampicillin, or weeks after your treatment has stopped. If you have symptoms like persistent diarrhea, pain in your stomach or cramping, or mucus or blood in your stool, seek guidance from a doctor.  

Use of medications like Ampicillin for a prolonged time or repeated periods might result in new infections in the mouth or vagina. If you notice any patches of white skin in your mouth, or a change in vaginal discharge, contact your doctor to ask whether you should continue using this medication. It’s worth noting that Ampicillin can also cause a mild rash. However, it is difficult to tell the difference between a rash that isn’t serious, and one that could be a sign of a significant allergic reaction. If you develop any kind of rash, it is best to seek immediate medical attention.  

You should also seek help immediately if you notice any other signs that could indicate that you may be having an allergic reaction to Ampicillin. Some side effects might include swelling around your throat, tongue, or face, itching and rashes, dizziness, or problems with your breathing. Remember, this list does not cover all possible side effects that may occur when taking Ampicillin. If you notice any other reactions that worry you when you are using this medication, you should seek help or advice from a medical professional.  

When shouldn’t you use Ampicillin? 

Not everyone will be able to use Ampicillin and other penicillin based antibiotics safely. Before you are given a prescription for this medication, you will need to answer all of the questions that your consultant asks truthfully and ensure that you provide your consultant with an insight into your medical history.  

You should not take Ampicillin if you have any allergies to penicillin antibiotics, or if you have any other allergies that could cause you to react poorly to this medication. This product can contain inactive ingredients which cause other problems, including allergic reactions. Before using Ampicillin, make sure that your consultant is aware of any kidney issues that you may have had in the past, including kidney disease. You will also need to tell your consultant about viral infections that you may have had recently.  

In some cases, taking Ampicillin can cause live vaccines in your system not to work as well as they should. You should not have any vaccinations or immunizations while taking this particular drug, unless your doctor tells you otherwise. Additionally, it’s worth noting that kidney function can decline and suffer as you get older. This medication must be removed and filtered by the kidneys, which means that older people are more likely to be sensitive to this drug.  

This medication should only be used when it is obviously needed during pregnancy. It is important to discuss the benefits and risks of using Ampicillin with your doctor if you are concerned about using this medication when you are pregnant.  

Does Ampicillin interact with other medications? 

Ampicillin can interact with other medications. Your healthcare professional or consultant can help you to determine whether any of the drugs that you are already taking might interact poorly with Ampicillin to ensure that it is safe for you to use this substance. You should not begin to use or change the dosage of this medication before checking that it is safe first. 

Before you begin using this Ampicillin, tell your doctor about any prescription and over-the-counter drugs that you are using, particularly if you are using methotrexate or tetracyclines. Ampicillin can cause positive results with certain urine testing products used to diagnose diabetics. In some cases, this drug may also alter the affects of other lab tests. Make sure that your doctors and lab personnel know that you are taking Ampicillin.  

Where can you buy Ampicillin? 

You should always see your doctor face to face, to be assessed to see if you need antibiotics and which is best suited.   If a prescription is given to you, then you will be able to collect it from a local pharmacy within three working days.  

Can I get Ampicillin without a prescription? 

Ampicillin, like most antibiotics, will not be available without a prescription. You will need a full consultation before you can get this medication.  

Sources, online, 2019, “Ampicillin”[Accessed 18th of December 2019], Available on: 

Medicine.Net, online, 2019, “Ampicillin”[Accessed 18th of December 2019], Available on: 

MedlinePlus, 2019, “Ampicillin” [Accessed 18th of December 2019], Available on: 

NICE, online, 2019, “AMPICILLIN”, [Accessed 18th of December 2019], Available on: 

Assessed by:

Dr Imran Malik, General practitioner
Registration number: GMC: 4741365

Dr Imran Malik studied undergraduate medicine at King's College University in Central London and clinical studies at the prestigious King's College Hospital. He graduated with a MBBS degree in 2000 and went on to gain postgraduate memberships with the Royal Society of Medicine and also General Practice in 2006.