Difference Between Penicillin and Amoxicillin

Penicillin and amoxicillin are both antibiotics sold in the market. Both hail from the penicillin family  and are derived from the fungus Penicillium. The difference between penicillin and amoxicillin is subtle, but their side effects and what bacteria they fight do differ. Both are used to treat bacterial infections but will not work on sickness caused by viruses.

Penicillin is a group of antibiotics used to counter bacterial infections. The medications come in oral tablets or solutions. Penicillin is given to people suffering from upper respiratory tract infections, mild skin infections, and scarlet fever. It is relatively affordable compared to amoxicillin and is typically covered by health insurance. Penicillin has the same potential side effects as amoxicillin but also includes nausea. Severe effects are limited to allergic reactions and severe diarrhea.

Amoxicillin is a semisynthetic form of penicillin that is more effectively absorbed by the body when taken orally. It is used for mild to moderate upper respiratory tract infections, tooth infections, UTI, and ulcers. Brand-name amoxicillins are less affordable than penicillin and generic versions of amoxicillin. Possible side effects include a mild skin rash, upset stomach, vomiting, diarrhea, and a black, hairy tongue. Amoxicillin has more severe possible side effects compared to penicillin – allergic reactions, bloody diarrhea, and seizures are some of the more serious effects the medication can cause on the human body.

Comparison Board

Penicillin
Amoxicillin
Definition A group of antibiotics made to combat bacterial infections A semisynthetic form of penicillin
Source The fungus Penicillium The fungus Penicillium
Fights against Bacterial infections Bacterial infections
Forms of use/consumption Intravenous, intramuscular and oral Intravenous, intramuscular and oral
Side effects Scarlet fever, mild skin infections, mild-moderate upper respiratory tract infections Mild-moderate upper respiratory tract infections, UTI, tooth infections, ulcers, mild skin infections
Health insurance Mild rash, upset stomach, diarrhea, vomiting, black and hairy tongue, nausea, allergic reaction, bloody/watery diarrhea Same as penicillin but no nausea, plus possible effects like bleeding and bruising, seizures, yellow eyes/skin
Brand-name forms Typically covered Typically covered, brand name versions may need authorization
Forms of use/consumption N/A Amoxil, Moxatag

Venn Diagram

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