Penicillin G
“This page provides important general information for pet owners whose animals have been prescribed Penicillin G during a consultation by Dr Noor.”
Penicillin G for pets in Perth
(pen-i-sill-in jee)
Description:
Penicillin G is a type of antibiotic medicine.
Other Names for this Medication:
- Pfizerpen®
- VetOne Pro®
- VetriPen G®
Common Dosage Forms:
- For animals:
- Procaine Penicillin G 300,000 units/mL, a liquid that is injected, sold in 100 mL and 250 mL bottles.
- For people:
- Penicillin G Sodium powder that is mixed for injection, available as 5 million units; and
- Penicillin G Sodium powder that is mixed for injection, available as 20 million units.
Antimicrobial Classification:
Critically Important
This information page does not include every detail that exists about this medicine. It is meant to address common questions, but it does not replace advice from a medical professional. If you still have questions or need additional details about this medicine, speak with your veterinarian or your pharmacist.
Key Information
- Penicillin G is most often given as a shot; giving it by mouth is not common.
- Procaine penicillin G must not be injected into a vein.
- Liquid medicines that are injected may sting when they are given under the skin (SC, meaning under the skin).
How is this medication useful?
Penicillin G is an antibiotic that may be used to treat some bacterial infections. Penicillin G is approved for use in animals. You and your veterinarian can talk about why this medicine is the best option.
What should I tell my veterinarian to see if this medication can be safely given?
Many different factors can change how well this medicine works for your animal. Talk with your veterinarian about the points below so you can make treatment choices together.
- Some medicines can affect penicillin G. Tell your veterinarian and pharmacist about everything your animal receives, including medicines, vitamins, supplements, or herbal products. Also share how much you give and when you give each one.
- Tell your veterinarian about any health problems your animal has now, or has had before.
- If your animal has had treatment in the past for the same illness or problem, tell your veterinarian what was used and whether it helped or did not help.
- If your animal is pregnant or nursing, discuss with your veterinarian what risks may come with using this medicine.
- Tell your veterinarian and pharmacist about any side effects your animal has had from medicines before. This includes allergic reactions, not wanting to eat, diarrhea, itching, or hair loss.
How long until I will know if this medication is working, and how long will the effects of this medication last?
This medicine should begin to work within 1 to 2 hours, but you may not be able to see changes on the outside. Your animal should start to seem better within 1 to 2 days.
This medicine does not last long in the body. It stops working within 24 hours, although the helpful effects may last longer if your animal’s kidneys and/or liver are not working normally.
When should this medication not be used or be used very carefully?
No medicine is completely safe for every patient. Your veterinarian will talk with you about any special concerns for your animal.
This drug SHOULD NOT be used in patients:
- If your animal is allergic to this medicine or similar medicines (other penicillins).
This drug should be used WITH CAUTION in patients:
- If your animal has problems with body salts/minerals (electrolyte disorders) or has heart disease.
- If your animal has had an allergic reaction to this medicine or to related antibiotics (for example, cephalosporins).
- Penicillin G procaine should be used carefully, or possibly not used, in snakes, rabbits, guinea pigs, gerbils, hamsters, or chinchillas, because these animals may react more strongly or be more sensitive to this form of the antibiotic.
If your animal has any of these issues, discuss with your veterinarian how the possible risks compare with the possible benefits.
What are the side effects of this medication?
Common but not serious side effects include:
You do not need to panic if you notice these signs unless they are strong, get worse, or do not go away. If that happens, contact your veterinarian.
- Diarrhea, vomiting, and not wanting to eat.
- Stinging where the shot was given.
Side effects that may be serious or indicate a serious problem:
If you notice any of the signs below, contact your veterinarian right away.
- A cat that stops eating completely can develop serious liver problems.
- Fever, skin rashes, trouble breathing, and pale gums can be signs of an allergic reaction.
If my animal gets too much of this medication (an overdose), what should I do?
Too much penicillin G can be dangerous. It may cause problems with body salts/minerals (electrolyte imbalances) and may harm the nervous system, as well as the liver. If you see or suspect an overdose, contact your veterinarian or an animal poison control center for guidance. These animal poison control centers are available 24 hours a day.
How should this medication be given?
To help this medicine work as intended, give it exactly the way your veterinarian prescribed it. It is helpful to read the prescription label each time so you confirm you are giving it correctly.
By Injection:
For Penicillin G potassium or sodium:
- Your veterinarian or pharmacist will provide what you need to give injections (such as needles and syringes). If the medicine must be mixed before use, mix it exactly the way your veterinarian or pharmacist tells you.
- Use a fresh needle and a fresh syringe each time you mix a bottle and each time you give an injection. Do not use needles or syringes again.
- Because this medicine is given by injection, make sure you understand the correct dose, where to give the injection, and how to give it.
- When adding the mixing liquid (diluent) to a bottle of penicillin, it is very important to balance the pressure inside the bottle. Your pharmacist or veterinarian will show you how to add the liquid so the penicillin does not spray out of the bottle.
- After you add the mixing liquid, shake bottles of penicillin G sodium or potassium until the liquid looks clear. Your veterinarian will usually tell you to mix the full bottle of penicillin G into another bag of fluids so it can be given under the skin.
- If these solutions are not mixed exactly as directed, they can break down quickly, and they must be kept in the refrigerator. After mixing, the expiration time depends on the product, but it cannot be more than 7 days. Do not use any penicillin G that has been mixed after that expiration time.
For Procaine Penicillin G:
- Shake this medicine very thoroughly before every dose. Before giving it, check that penicillin G procaine is not settled in a layer at the bottom of the bottle.
- Procaine penicillin G must be injected into a muscle and not into a vein.
- This medicine may sting when injected. If your animal reacts strongly to the injections, your veterinarian may be able to provide something to combine with the penicillin G to reduce the stinging.
This medicine may be prescribed for different lengths of time. Make sure you understand how long your veterinarian wants you to keep giving it. You may need prescription refills before the full treatment is finished. Speak with your veterinarian before you stop this medicine, because there may be important reasons to keep using it.
What should I do if I miss giving a dose of this medication?
If you forget a dose, give it as soon as you remember. If it is almost time for the next dose, do not give the missed one; instead, give the next dose at the regular time. Then continue with the normal schedule. Do not give two doses at once and do not give extra doses.
How should I store this medication?
- Keep this medicine in the original prescription container, the original bottle, or another container your pharmacist or veterinarian provided.
- Unmixed powder bottles can be kept at room temperature. After mixing into a liquid, it must be stored in the refrigerator.
- Procaine Penicillin G must always be kept in the refrigerator.
- If your veterinarian or pharmacist has prepared a custom-made version (compounded) for your animal, follow the storage directions and the expiration date that come with that product.
- Store where children and other animals cannot reach it.
Can handling this medication be hazardous to me, my family, or other animals?
No special handling steps are needed unless you are allergic to this medicine. After you handle any medicine, wash your hands.
How should I dispose of this medication if I don’t use it all?
- Do not pour this medicine into a toilet or down a sink. If your area has a medicine “take-back” program, use that option.
- If there is no take-back program, combine the medicine with used coffee grounds or cat litter so it is unpleasant to children and animals and not recognizable to people who might search through trash. Put that mixture into a sealable plastic bag to prevent leaks, and place it in the household trash.
- Do not keep leftover medicine to use later, and do not give it to anyone else.
What other information is important for this medication?
- This medicine may be prohibited in some animal competitions. Before entering a competition while your animal is receiving this medicine, check the rules.
- If you have more questions about this medicine, contact your veterinarian or pharmacist.
“Disclaimer: The information on this page is provided as general educational material only. Every animal’s health situation is unique, and treatment decisions must be based on a full veterinary assessment. Always follow the specific instructions given during your consultation, and contact the prescribing veterinarian if you have any concerns.”