Crystapen injection contains the active ingredient benzylpenicillin, which is a type of medicine called an antibiotic. It is used to treat infections caused by bacteria.
Benzylpenicillin works by interfering with the ability of bacteria to form cell walls. The cell walls of bacteria are vital for their survival. They keep unwanted substances from entering their cells and stop the contents of their cells from leaking out. Benzylpenicillin impairs the bonds that hold the bacterial cell wall together. This allows holes to appear in the cell walls and kills the bacteria.
Benzylpenicillin is a broad-spectrum antibiotic that kills a wide variety of bacteria that cause a wide variety of commonly-occuring infections. Benzylpenicillin may be used to treat infections of the lungs and airways, mouth and throat, skin or soft tissue, or ears, as well as other more rare infections.
To make sure the bacteria causing an infection are susceptible to benzylpenicillin your doctor may take a tissue sample, for example a swab from the throat or skin, or a blood sample.
Benzylpenicillin is given by injection into a vein or muscle, or via a drip into a vein.
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while having treatment with this one, to make sure that the combination is safe.
If you are taking the contraceptive pill and experience vomiting or diarrhoea as a result of treatment with this antibiotic, you should follow the instructions for vomiting and diarrhoea described in the leaflet provided with your pills.
Benzylpenicillin may decrease the removal of the medicine methotrexate from the body, which could increase the risk of its side effects. If you are taking methotrexate your doctor may want you to have extra check-ups and blood tests while you are having a course of this antibiotic.
Benzylpenicillin may rarely alter the anti-blood-clotting effects of anticoagulant medicines such as warfarin. Your doctor may wish to monitor your blood clotting time (INR) more frequently while you are being treated with both medicines.
Oral typhoid vaccine (Vivotif) should not be taken until at least three days after you have finished a course of this antibiotic, because the antibiotic could make this vaccine less effective.
Probenecid may increase the blood level of benzylpenicillin, and people taking probenecid may be prescribed a lower than normal dose of this antibiotic.
There are currently no other medicines available in the UK that contain benzylpenicillin as the active ingredient.