Interactions
It may potentiate the antihypertensive effects of:

Drugs subject to a strong first-pass effect such as beta blockers may increase the bioavailability of hydralazine. Epinephrine (adrenaline), by its heart rate-accelerating effects as increased by hydralazine,  may lead to toxicity. Mechanism of action
Hydralazine is a drug that conducts the blood pressure lowering effects by vasoconstrictive repression. It is a direct-acting smooth muscle relaxant and acts as a vasodilator primarily in resistance arterioles, also known as the smooth muscle of the arterial bed. The molecular mechanism involves inhibition of inositol trisphosphate-induced Ca2+ release from the sarcoplasmic reticulum in arterial smooth muscle cells. By relaxing vascular smooth muscle, vasodilators act to decrease peripheral resistance, thereby lowering blood pressure and decreasing afterload. Chemistry
Hydralazine belongs to the hydrazinophthalazine class of drugs. History
The antihypertensive activity of hydralazine was discovered by scientists at Ciba, who were trying to discover drugs to treat malaria; it was initially called C-5968 and 1-hydrazinophthalazine; Cibas patent application was filed in 1945 and issued in 1949, and the first scientific publications of its blood pressure-lowering activities appeared in 1950. It was approved by the FDA in 1953.It was one of the first antihypertensive medications that could be taken by mouth. Research
Hydralazine has also been studied as a treatment for myelodysplastic syndrome in its capacity as a DNA methyltransferase inhibitor. See also
Arteriolar vasodilator
Cadralazine
Dihydralazine
Endralazine
Sodium nitroprusside

References
External links
"Hydralazine". Drug Information Portal. U.S. National Library of Medicine.
Hematospermia (also known as haematospermia, hemospermia, or haemospermia) is the presence of blood in ejaculation. It is most often a benign symptom. Among men age 40 or older, hematospermia is a slight predictor of cancer, typically prostate cancer. No specific cause is found in up to 70% of cases. Cause
Though haematospermia may cause considerable distress to patients, it is often a benign and self-limiting condition caused by infections, particularly in younger patients. An isolated episode is usually considered benign and not likely to be associated with malignancy. Recurrent haematospermia may indicate a more serious underlying pathology particularly in patients over 40 years of age. Infection and inflammation
Infection or inflammation is considered the most common cause of the condition. Implicated pathogens include; Gram-negative bacteria (often E. coli), gonococci, T. pallidum, C. trachomatis, N. gonorrhoeae, echinococcus (rarely), HSV type 1 or 2, and HPV. The condition may also rarely be caused by some chronic systemic infections like tuberculosis or schistosomiasis. Additionally, testicular, prostate, and epididymal inflammation in general may present with haematospermia as feature. Neoplasm
Some neoplasms of the genitourinary system may present with haematospermia. Malignant causes of haematospermia include; prostate cancer, testicular or epididymal tumours, seminal vesicle carcinoma (rarely), and urethral tumour. Lymphomas and leukaemias may also feature haematospermia as symptom. Prostate
Various prostate pathologies (including prostatitis, calculi (stones), cysts, benign prostatic hyperplasia, bacterial infection, etc.) may result in blood occurring in the ejaculate. Other
Systemic conditions like malignant hypertension, liver dysfunction, or bleeding disorders, and amyloidosis may sometimes present with haematospermia as symptom.