Doxycycline (refers to doxycycline hydrochloride for injection) generally does not cause low blood pressure, the specific medication as prescribed by the doctor. 1. Doxycycline is a tetracycline antibiotic with broad-spectrum bacteriostatic or bactericidal effect, which is suitable for the treatment of rickettsial diseases (such as typhus, Rocky Mountain Fever, Tsutsugamushi fever and Q fever), Mycoplasma pneumoniae, psittacosis, avian influenza pathogens, and many other infectious diseases. 2.The drug should be contraindicated in patients with a history of hypersensitivity to any of the tetracyclines. Adverse reactions such as anorexia, nausea, vomiting, abdominal pain, tongue inflammation, maculopapular rash, erythema and other adverse reactions may occur after the use of the drug, and generally do not cause adverse reactions such as lowering of blood pressure. Specific medication should be administered under the guidance of a specialist.