Paracetamol.pptx

it elaborates the drug type,class and its metaloblism along with uses

1. Paracetamol Medicine in chemistry

2. Outline 1. introduction 2. Metabolism 3. Classical synthesis method of paracetamol 4. Celanese method 5. pharmacokinetics 6. Pharmacodynamics 7. Side effect of paracetamol 8. overdose of paracetamol 9. precautions

3. 1. Introduction Paracetamol is a painkilling (analgesic) medicine available over-the-counter without a prescription. Paracetamol can be used to: ease mild to moderate pain ‐ for example,  headaches ,  sprains , or  toothache control a fever (high temperature, also known as pyrexia) ‐ for example , when someone has the  flu  (influenza ).

4. Contin… At a standard dose, paracetamol only slightly decreases body temperature ;  it is inferior to  ibuprofen  in that respect ,  and the benefits of its use for fever are unclear . Common brand names include Tylenol and Panadol . Paracetamol is available in the following forms: Tablets Capsules Suppositories Soluble powders Liquids

5. Contin… Formula C 8 H 9 NO 2 Molar mass 151.165 g·mol −1 Density 1.263 g/cm 3 Melting point 169 °C (336 °F)  Solubility in water 7.21 g/kg (0 °C) Drug class Analgesics and antipyretics Bioavailability 63–89%   Protein binding negligible to 10–25% in overdose Metabolism Predominantly in the liver Onset of action By mouth  – 37 minutes Intravenous  – 8 minutes Elimination  half-life 1.9–2.5 hours

6. 2. Metabolism of paracetamol Paracetamol is  metabolized  primarily in the liver, mainly by  glucuronidation  and  sulfation , and the products are then eliminated in the urine. Only 2–5% of the drug are excreted unchanged in the urine. Glucuronidation is facilitated by enzymes  accounts for 50–70% of the drug metabolism. Additional 25–35% of paracetamol is converted to sulfate by sulfation enzymes.

7. N-acetyl-p-benzoquinone imine,

8. This aminophenol goes to brain where it interacts with the cannabinoid receptors. These receptors after interacting with aminophenol exhibits analgesic effects.

9. 3. Classical synthesis method of paracetamol The classical methods for the production of paracetamol involve the  acetylation  of  4-aminophenol  with  acetic anhydride  as the last step. They differ in how 4-aminophenol is prepared. In one method,  nitration  of  phenol  with  nitric acid  affords  4-nitrophenol , which is reduced to 4-aminophenol by  hydrogenation  over  Raney nickel . In another method,  nitrobenzene  is reduced  electrolytically  giving 4-aminophenol directly.

10. 4. Celanese method of synthesis An alternative industrial synthesis developed at  Celanese  involves direct acylation of phenol with acetic anhydride in the presence of  hydrogen fluoride , conversion of the resulting ketone to a  ketoxime  with  hydroxylamine , followed by the acid-catalyzed  Beckmann rearrangement

11. Beckman rearrangement

12. 5. Pharmacodynamics Paracetamol is a p-aminophenol derivative that exhibits analgesic and antipyretic activity. It does not possess anti-inflammatory activity. Paracetamol is thought to produce analgesia through a central inhibition of prostaglandin synthesis . Paracetamol appears to exert its effects through two mechanisms: the inhibition of  cyclooxygenase  and actions of its metabolite  AM404

13. 6. Pharmacokinetics After being taken by mouth, paracetamol is rapidly absorbed from the  small intestine , while absorption from the stomach is negligible. Thus, the rate of absorption depends on stomach emptying. Food slows the stomach emptying and absorption, but the total amount absorbed stays Paracetamol's  bioavailability  is dose-dependent: it increases from 63% for 500 mg dose to 89% for 1000 mg dose .  Its plasma terminal elimination half-life is 1.9–2.5 hours, and  volume of distribution  is roughly 50 L. Protein binding is negligible, except under the conditions of overdose, when it may reach 15–21%. The concentration in serum after a typical dose of paracetamol usually peaks below 30 μg/mL (200  μmol /L). After 4 hours, the concentration is usually less than 10 μg/mL (66  μmol /L ).

14. 7. Side effects of paracetamol Side effects from paracetamol are rare but can include: an  allergic reaction , which can cause a rash and swelling flushing,  low blood pressure  and a fast heartbeat – this can sometimes happen when paracetamol is given in hospital into a vein in your arm blood disorders, such as thrombocytopenia (low number of platelet cells) and leukopenia (low number of white blood cells) liver and kidney damage, if you take too much (overdose) – this can be fatal in severe cases

15. Contin… drowsiness and fatigue rashes and itching . Children may occasionally experience low blood sugar and tremors, and feeling hungry, faint and confused after taking paracetamol. 1

16. Paracetamol poisoning Overdoses  of paracetamol, that is, taking more than the recommended maximum daily dose of paracetamol for healthy adults of three or four grams, can cause potentially fatal  liver damage . Paracetamol toxicity  is the foremost cause of  acute liver failure . Untreated paracetamol overdose results in a lengthy, painful illness. Signs and symptoms of paracetamol toxicity may initially be absent or  non-specific symptoms . The first symptoms of overdose usually begin several hours after ingestion, with  nausea ,  vomiting , sweating, and  pain  as  acute liver failure  starts People who take overdoses of paracetamol do not fall asleep or lose consciousness, although most people who attempt suicide with paracetamol wrongly believe that they will be unconscious by the drug.

17. 8. Overdose of paracetamol Taking too much paracetamol, known as an overdose, can be very dangerous . There is no safe level of drug use.  Use of any drug always carries some risk – even medications can produce unwanted side effects. Paracetamol affects everyone differently, based on: size, weight and health whether the person is used to taking it whether other drugs are taken around the same time the amount taken .

18. Contin… Tiredness Breathlessness Bluish tinge to fingers and lips Anemia (low red blood cell count) Liver and kidney damage

19. 9. Precautions Always get advice before taking paracetamol if you: have liver or kidney problems have problems with alcohol, such as long-term alcohol misuse. are very underweight are taking other medications

20. Thank you!