Monday disease is an occupational effect seen in workers exposed repeatedly to volatile organic nitrates, especially nitroglycerin and ethylene glycol dinitrate in explosives manufacture.

It is distinct from Monday fever, a term often used for the beginning-of-week respiratory symptoms of byssinosis in cotton-textile workers.

Katzung describes this as recurring headache and transient dizziness after Monday re-exposure to high workplace nitrate levels, with disappearance after tolerance develops again. Katzung's Basic and Clinical Pharmacology, 16th ed., lines 4076-4081. Occupational nitrate withdrawal can also cause rebound coronary vasospasm or angina in susceptible workers, as described by the ATSDR nitrate toxicology review.

No. Statins generally do not decrease HDL cholesterol. They usually cause a small increase in HDL-C, often about 5% to 10%, while their main effect is lowering LDL cholesterol and cardiovascular risk. Goodman & Gilman’s The Pharmacological Basis of Therapeutics, section “Effect of Statins on HDL-C Levels.”

A low HDL result while taking a statin is more likely related to the underlying metabolic profile, such as high triglycerides, diabetes, smoking, obesity, or inactivity, rather than the statin itself. Treatment decisions primarily target lowering LDL/non-HDL cholesterol and overall cardiovascular risk, not raising HDL alone.

Niacin (nicotinic acid) increases HDL cholesterol, often by about 15% to 35%. It also lowers triglycerides and can lower LDL-C and lipoprotein(a). The Washington Manual of Medical Therapeutics reports an HDL rise of up to 35%.

However, niacin is not routinely added to statins simply to raise HDL. Large trials did not show additional cardiovascular benefit from raising HDL with niacin when LDL was already well controlled on a statin, while adverse effects were more frequent.

Important adverse effects:

So: Niacin raises HDL, but an improved HDL number does not necessarily mean improved cardiovascular outcomes.