Optical isomerism in Thalidomide - Essay Example

The tragedy which occurred due to thalidomide use led to very stringent testing requirement for pesticides and drugs before licensing. Initially, thalidomide was prescribed as effective painkiller and tranquilizer for insomnia, colds, coughs, and headaches. It was a very effective antiemetic inhibiting morning sickness, and this resulted into many pregnant women using thalidomide in order relieve their pregnancy symptoms. The relationship between the drug and defects in birth were suspected by Australian obstetrician, McBride William, and the German pediatrician, Lenz Widukind.

This was later proven in 1961 by Lenz. Approximately 2500 thalidomide babies were born in Germany. The United States Congress constituted laws demanding safety tests during pregnancy before approving any drug. Other nations have passed similar laws too. This has seen thalidomide not sold or prescribed in several countries for decades1. The severe thalidomide impacts led to strict tests being carried out. The drug was tested as a one single agent for treating multiple myeloma because of its ant angiogenesis activity during the research trials.

Many studies have illustrated that thalidomide in combination with dexamethasone increases the rate of survival of the patients of multiple myeloma2. However, commercially produced drug differed from the one used during the research trials, and this resulted into other thalidomide effects. The commercially produced drug differed from that used in research trials in that during commercial productions, thalidomide was produced in combination with dexamethasone and melphalan, which is today the regimen most common for the patients who are newly diagnosed with multiple myeloma.

This has seen the development of other side effects such as fatigue, polyneuropathy, venous thromboembolism (VTE), skin rush, or blood clot, which may result into myocardial infarction or stroke. Several scientists have made reviews on VTE relationship with thalidomide in multiple myeloma diagnosed patients, and the results show that thalidomide administered without prophylaxis leads to a high rate of VTE (26%). Owing to this high VTE rates with thalidomide combined with doxorubicin or dexamethasone, which is commercially produces, a black box warning was given in 2006 in the United States to the thalidomide package showing that multiple myeloma patients receiving thalidomide-dexamethasone bay concurrently benefit from thromboembolism prophylaxis or aspirin.

There has been production of other thalidomide derivatives such as lenalidomide and bortezomib3. The presence of optical isomers severely affects fetal development in pregnant women. Tests from the laboratory after the thalidomide disaster indicated that in some animals the 'R' isomer was an effective sedative, but the 'S' enantiomer was tetragenic. The presence of the optical isomers may also lead to phocomelia which is characterized by shortened limbs, or even complete absence. In addition, fetus may develop hypo plastic or external ear abnormalities, facial palsy, malfunctions of genitourinary and gastrointestinal tract, or even complete absent bones.

Approximately 40% of such fetuses die after birth4. Conclusion To sum up, there is no acute toxicity in thalidomide and a fatal overdose may be impossible virtually. As a component of thalidomide, Citalopram has severe effects with the dosage of thalidomide. This is because Citalopram and peripheral