Tetracycline, sold under various brand names, is an oral antibiotic in the tetracyclines family of medications, used to treat a number of infections, including acne, cholera, brucellosis, plague, malaria, and syphilis.Common side effects include vomiting, diarrhea, rash, and loss of appetite. Other side effects include poor tooth development if used by children less than eight years of age, kidney problems, and sunburning easily. Use during pregnancy may harm the baby. It works by inhibiting protein synthesis in bacteria.Tetracycline was patented in 1953 and came into commercial use in 1978. It is on the World Health Organizations List of Essential Medicines. Tetracycline is available as a generic medication. Tetracycline was originally made from bacteria of the Streptomyces type. Medical uses
Spectrum of activity
Tetracyclines have a broad spectrum of antibiotic action. Originally, they possessed some level of bacteriostatic activity against almost all medically relevant aerobic and anaerobic bacterial genera, both Gram-positive and Gram-negative, with a few exceptions, such as Pseudomonas aeruginosa and Proteus spp., which display intrinsic resistance. However, acquired (as opposed to inherent) resistance has proliferated in many pathogenic organisms and greatly eroded the formerly vast versatility of this group of antibiotics. Resistance amongst Staphylococcus spp., Streptococcus spp., Neisseria gonorrhoeae, anaerobes, members of the Enterobacteriaceae, and several other previously sensitive organisms is now quite common. Tetracyclines remain especially useful in the management of infections by certain obligately intracellular bacterial pathogens such as Chlamydia, Mycoplasma, and Rickettsia. They are also of value in spirochaetal infections, such as syphilis, and Lyme disease.
Hemoperitoneum  (also haemoperitoneum, sometimes also hematoperitoneum) is the presence of blood in the peritoneal cavity. The blood accumulates in the space between the inner lining of the abdominal wall and the internal abdominal organs. Hemoperitoneum is generally classified as a surgical emergency; in most cases, urgent laparotomy is needed to identify and control the source of the bleeding. In selected cases, careful observation may be permissible. The abdominal cavity is highly distensible and may easily hold greater than five liters of blood, or more than the entire circulating blood volume for an average-sized individual. Therefore, large-scale or rapid blood loss into the abdomen will reliably induce hemorrhagic shock and, if untreated, may rapidly lead to death. Causes
Causes of hemoperitoneum include:
Penetrating trauma
Blunt trauma, most commonly injuries to solid organs such as the liver and spleen. Vascular accidents, such as rupture of an abdominal aortic aneurysm, iliac aneurysm, or splenic aneurysm. Bleeding due to a ruptured ectopic pregnancy or uterine rupture. Rupture of corpus luteum in some cases. Less commonly, bleeding due to a perforated gastric ulcer. Bleeding due to rupture of an intra-abdominal neoplasm, (e.g., Hepatoblastoma)
Disseminated intravascular coagulation
People on high dose of anticoagulants (blood thinners)
Perforation of the colon

Diagnosis
Hemoperitoneum can be reliably diagnosed with the following examinations:
Focused assessment with sonography for trauma (FAST)
Paracentesis or diagnostic peritoneal lavage
Computed tomography
Diagnostic laparoscopy or exploratory laparotomy

Treatment
Initial management consists of immediate blood transfusion if the patient is in hemorrhagic shock.