Benadryl tablets are effective in lowering blood pressure and side effects include headache, dizziness, fatigue, drowsiness, nausea and cough. The use of medication should be directed by a physician. Benadryl is an angiotensin I-converting enzyme inhibitor, which lowers blood pressure by inhibiting the renin-angiotensin-aldosterone system, and is used to treat congestive heart failure in addition to hypertension. Common side effects of the drug are headache, dizziness, fatigue, drowsiness, nausea, cough, and, less commonly, low blood pressure, syncope, palpitations (rapid heartbeat, often accompanied by panic), edema, dermatitis, constipation, gastritis, anxiety, and insomnia. The occurrence of the above side effects is not absolute and is related to individual reactivity. The drug is contraindicated in allergy, angioneurotic edema, isolated kidneys, kidney transplantation, patients with bilateral renal artery stenosis, pregnant women. , Patients with hypertension need to use the drug under the supervision of a physician, and if any adverse reactions occur after the use of this drug, it is necessary to stop the drug and seek medical attention.