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Ampicillin – The Trusted Antibiotic for Bacterial Infections

Penicillin, the first antibiotic, was discovered by Alexander Fleming in 1928. It was found to be effective against gram-positive bacteria but not against gram-negative bacteria. This led to the development of new antibiotics, such as Ampicillin, which could target a broader range of bacteria. 

Essentially, it means that Ampicillin is a more versatile drug compared to the earlier solutions. It’s still related to Penicillin and also has a particular focus on specific bacteria, essentially. Ampicillin is a rather popular drug all over the world, and it’s also pretty affordable.

Ampicillin was developed by scientists at Beecham Research Laboratories in the United Kingdom in the late 1950s. It was patented in 1961 and soon entered the market. Currently, it’s sold under many trademarks (Principen, most notably) and manufactured by various companies, including Pfizer.

How does Ampicillin function?

Ampicillin is a bacteriostatic antibiotic that inhibits the bacterial cell wall synthesis process, resulting in the demise of bacteria. This drug is effective against a wide range of gram-positive and gram-negative bacteria, including but not limited to Escherichia coli, Salmonella, Shigella, Streptococcus, and Staphylococcus aureus.

Thanks to its broad-spectrum antibacterial action, Ampicillin can treat various bacterial infections in numerous body systems. However, it may take more extended periods to complete the treatment compared to some other antibiotics. Typically, a treatment course of Ampicillin lasts two weeks, whereas Penicillin usually takes ten days, although this varies depending on the disease.

Ampicillin is commonly employed to address respiratory tract infections, urinary tract infections, skin infections, and gastrointestinal tract infections. Moreover, the medication is also useful for preventing bacterial infections during surgical procedures, when the body is most susceptible.

Buying Ampicillin

The drug is generally regarded as one of the more affordable solutions. The usual price in the US can reach $2 per 500mg pill, but cheaper options can also be found. In general, it’s a lot cheaper if you buy generic options, which are scarcely found in America anyway.

Buying in Canada is also generally a good idea because medicine is cheaper over there. While the usual price for Ampicillin products in the US is ~$2 per pill, it’s fairly common to find pills that cost $0.2-0.6 in Canada. These are mostly generic versions sold as Ampicillin proper, instead of Principen and other names.

The generic pills are absolutely identical in quality and safety. It’s the same pure Ampicillin compound as originally discovered. This type is usually manufactured by lesser-known companies, but the quality control is on par with the big corporations. The only difference is really the price, and generics are on a much cheaper end. 

Adverse Effects

Ampicillin is a relatively mild antibiotic compared to some of the more strong options. Nonetheless, it has a few contraindications. Individuals allergic to Penicillin are likely to have an Ampicillin allergy. The drug is contraindicated in patients with dialysis, renal problems, asthma, and eczema.

Common side effects of Ampicillin are diarrhea, nausea, vomiting, and skin rash, which are usually mild and self-limiting. In rare cases, however, the drug can cause severe allergic reactions, liver damage, and kidney damage. If you experience any of these symptoms, seek medical attention promptly.

It is essential to inform your doctor of your medical history, including any liver or kidney disease, asthma, or allergies, before starting Ampicillin. This medication may also interact with other medications, so it is crucial to inform your doctor of all the drugs you are taking before beginning treatment.

Although Ampicillin is generally regarded as safe to use during pregnancy and breastfeeding, it is vital to consult your doctor before taking the drug if you are pregnant or nursing, as with any medication.


The usual dosage of Ampicillin varies depending on various factors, such as age, weight, height, as well as the severity of the infection, and the disease being treated. For adults, the usual dose of Ampicillin is 250mg to 500mg taken four times a day. For children, the dose is usually calculated based on their weight. 

Going above 500mg is very ill-advised, and can lead to an overdose. In case of an overdose, the symptoms may include nausea, vomiting, diarrhea, abdominal pain, and seizures. You should seek help immediately if you suspect an Ampicillin overdose. Fatal cases are rare, and you need to take immense amounts of it for that to happen.


Ampicillin is a prescription drug throughout the world. Although it is a comparably milder medicine, it’s still an antibiotic with many possible ill side effects. You can get the necessary prescription from a nearby doctor or through online consultation. It is better, however, if you go to the hospital to get it prescribed.

As mentioned, it can be possible that you have some sort of Penicillin allergy, hypersensitivity, or, on the contrary, resistance to this compound. If that’s the case, it means you’ll buy a whole package of Ampicillin for naught. You can check for all the possible problems beforehand.


Ampicillin is a highly effective antibiotic that has been used for decades to treat a wide range of bacterial infections. Although it can cause side effects, the benefits of this medication far outweigh the risks. It is important to take Ampicillin as directed and to report any unusual symptoms to your healthcare provider.