habituation
A condition characterized by a psychological craving for the effects produced by the administration of a drug, as a desire rather than a compulsion, and an absence of physical dependence.
haemolysis (hemolysis)
Haemolysis is the rupture (lysis) or destruction of erythrocytes. Haemolysis can be caused by bacterial toxins (e.g. Gram +ve Streptococcal, Enterococcal or Staphylococcal toxins), parasites (e.g. Plasmodium sp.), autoimmune or genetic disorders, and can lead to haemoglobinemia (hemoglobinemia).
half-life
Half-life (t½) is an important pharmacokinetic measurement. The metabolic half-life of a drug in vivo is the time taken for its concentration in plasma to decline to half its original level. Half-life confers the duration of action of a drug and depends upon how quickly the drug is eliminated from the plasma. The clearance and distribution of a drug from the plasma are therefore important parameters for the determination of its half-life.
haplotype
A set of genetic variants that are inherited together.
hepatic drug clearance rate
Often referred to simply as hepatic clearance, this represents the rate at which the liver is able to remove drug during. It is influenced by the rate of blood flow to the liver and the efficiency of the liver to remove drug from the blood, which is reflected by the hepatic extraction ratio.
hepatic extraction ratio
The fraction of drug entering the liver in the blood that is irreversibly removed during a single pass through the liver.
heterochromatin
A tightly packed form of chromatin that is not actively being transcribed or is less accessible for transcription
histones
Eukaryotic proteins around which DNA is tightly wound. Histones function to condense and package DNA in the nucleus.