The Coronary Drug Project (CDP) was a large

clinical trial Clinical trials are prospective biomedical or behavioral research studies on human subject research, human participants designed to answer specific questions about biomedical or behavioral interventions, including new treatments (such as novel v ...

which assessed several different treatments for

coronary heart disease Coronary artery disease (CAD), also called coronary heart disease (CHD), or ischemic heart disease (IHD), is a type of cardiovascular disease, heart disease involving Ischemia, the reduction of blood flow to the cardiac muscle due to a build-up ...

in men with previous

myocardial infarction A myocardial infarction (MI), commonly known as a heart attack, occurs when Ischemia, blood flow decreases or stops in one of the coronary arteries of the heart, causing infarction (tissue death) to the heart muscle. The most common symptom ...

. The study was conducted from 1965 to 1985 at 53 clinical centers and randomized 8,341 men age 30 to 64 years to six different treatment groups: low-dose

estrogen Estrogen (also spelled oestrogen in British English; see spelling differences) is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three ...

therapy (2.5 mg/day

oral The word oral may refer to: Relating to the mouth * Relating to the mouth, the first portion of the alimentary canal that primarily receives food and liquid **Oral administration of medicines ** Oral examination (also known as an oral exam or ora ...

conjugated estrogens Conjugated estrogens (CEs), or conjugated equine estrogens (CEEs), sold under the brand name Premarin among others, is an estrogen medication which is used in menopausal hormone therapy and for various other indications. It is a mixture of th ...

), high-dose estrogen therapy (5 mg/day oral conjugated estrogens), clofibrate (1.8 g/day), dextrothyroxine (6 mg/day),

niacin Nicotinic acid, or niacin, is an organic compound and a vitamer of vitamin B3, an essential human nutrient. It is produced by plants and animals from the amino acid tryptophan. Nicotinic acid is also a prescription medication. Amounts f ...

(3 g/day), and

placebo A placebo ( ) can be roughly defined as a sham medical treatment. Common placebos include inert tablets (like sugar pills), inert injections (like saline), sham surgery, and other procedures. Placebos are used in randomized clinical trials ...

(

lactose Lactose is a disaccharide composed of galactose and glucose and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from (Genitive case, gen. ), the Latin word for milk, plus the suffix ''-o ...

3.8 mg/day). The high-dose estrogen group was discontinued in 1970 due to increased non-fatal

cardiovascular complication Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina, heart attack), heart failure, hypertensive heart disease, rheumatic h ...

s and an unfavorable trend in overall mortality, while the low-dose estrogen group was discontinued in 1970 due to lack of indication of benefit and also an unfavorable trend in overall mortality. Both dose levels of estrogen as well as clofibrate were also found to increase the incidence of

gallbladder disease Gallbladder diseases are diseases involving the gallbladder and is closely linked to biliary disease, with the most common cause being gallstones (cholelithiasis). The gallbladder is designed to aid in the digestion of fats by concentrating and ...

in the study. The dextrothyroxine group was discontinued in late 1971 due to increased cardiovascular mortality. The Coronary Drug Project Aspirin Study was a substudy of the CDP which randomized men from the estrogen and dextrothyroxine groups of the trial which had been terminated early to either

aspirin Aspirin () is the genericized trademark for acetylsalicylic acid (ASA), a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and inflammation, and as an antithrombotic. Specific inflammatory conditions that aspirin is ...

or placebo.

References

{{Reflist Clinical trials Evidence-based medicine Ischemic heart diseases