| Liver is a large reddish-brown glandular organ | | | | wide spectrum of liver injuries. These include, but |
| located in the upper right portion of the abdominal | | | | are not limited to: |
| cavity behind the rib cage. It secretes bile and | | | | Hepatitis: Certain drugs can cause acute and |
| functions in metabolism of proteins, carbohydrates | | | | chronic hepatitis (inflammation of liver cells) that |
| and fats. It is known to produce various factors | | | | can lead to necrosis i.e. cell death. Acute |
| involved in the clotting of the blood & synthesize | | | | drug-induced hepatitis lasts less than 3 months, |
| vitamin A. Liver also breaks down worn-out | | | | while chronic hepatitis lasts longer than 3 months. |
| erythrocytes (RBCs). As most of the chemical | | | | Some drugs that cause acute and chronic |
| compounds, whether taken orally or injected | | | | hepatitis include phenytoin, diclophenac, & |
| intravenously, are taken to liver, the majority of | | | | nitrofurantoin. |
| small-molecule drug metabolism is carried out in | | | | Fulminant hepatitis: Rarely, drugs cause acute liver |
| the liver by cytochrome P450 which are | | | | failure or fulminant (sudden & severe) hepatitis. |
| membrane bound oxidative enzymes which | | | | These patients are extremely ill with the |
| metabolize various endogenous and exogenous | | | | symptoms of acute hepatitis. |
| molecules. | | | | Cholestasis: It is a condition in which the secretion |
| Action of drugs: Drugs can lead to liver disorders | | | | and/ or flow of bile is reduced. Example- |
| in several ways. Some drugs are directly | | | | erythromycin, chlorpromazine etc. |
| deleterious to the liver while others are | | | | Mild elevations in blood liver enzyme levels: Many |
| transformed or metabolized by liver into chemicals | | | | drugs cause mild elevations in blood levels of liver |
| that can cause liver damage either directly or | | | | enzymes, often without any major symptoms. |
| indirectly. | | | | For example, statins & some antidepressants are |
| Dose-dependent toxicity: It occurs when any | | | | known to increase levels of liver enzymes in |
| given drug is taken in excess, the increased | | | | blood. |
| concentration of that drug or its metabolite may | | | | Necrosis: Blood clotting in the liver veins may |
| lead to liver damage. Such drugs are usually | | | | cause death of liver cells. For example, |
| harmless if taken within prescribed limits. For | | | | Pyrrolizidine alkaloids can cause blood clotting. |
| example, acetaminophen overdose is known to | | | | Cirrhosis: It is a chronic disease interfering with the |
| cause dose-dependent toxicity in liver. | | | | normal functioning of the liver due to scarring. |
| Idiosyncratic toxicity: Drugs that cause | | | | Drugs like amiodarone and methyldopa may lead |
| idiosyncratic toxicity cause disease in only those | | | | to Cirrhosis. |
| few individuals who have inherited specific genes | | | | Diagnosis: Diagnosis of liver disorders is based on a |
| that are associated in some way to the chemical | | | | patient's symptoms, which may vary from loss of |
| transformation of that particular drug. | | | | appetite, nausea, fatigue, itching, dark urine, to |
| Drug allergy: It occurs when a drug or its | | | | jaundice, enlarged liver etc. Laboratory testing |
| metabolite acts as an allergen which may initiate | | | | may also be used to detect blood liver enzymes |
| hypersensitivity reaction by the body's immune | | | | levels, bilirubin levels which may suggest abnormal |
| system leading to local inflammation that may | | | | liver behavior. An unusually long blood clotting time |
| damage liver tissues. | | | | may also be an indicative of a potential liver |
| Drug induced liver diseases: Various exogenous | | | | damage. |
| drugs and endogenous chemicals can cause a | | | | |