Mechanism of action of Paracetamol and brands and dosage of Ibuprofen

BY: KOMAL HALEEM PHARM-D

PARACETAMOL

OTC

Also known as,

ACETAMINOPHEN

DESCRIPTION

-Analgesic

-Antipyretic

-Central action> Peripheral action

-NO

GI disturbances

Acid-base imbalance

Electrolyte imbalance

Impairment of clotting

-ADR :

Extremely safe drug. But rarely produces …. Hepatic toxicity

Mechanism Of Action :

Inhibits the cycloxygenase

Enzyme

REDUCES PROSTAGLANDIN SYNTHESIS

MOST

IMPORTANT

MECHANISMS

BRAND NAMES

VANCOCIN

ELI LILLY PAKISTAN (PVT)

LTD.

VANCOMYCIN

ABBOTT LABORATORIES (PAKISTAN) LIMITED.

-acts primarily in the CNS

-increases the pain threshold by inhibiting both isoforms of cyclooxygenase,

-COX-1, COX-2 and COX-3 enzymes involved in prostaglandin (PG) synthesis.

When normal dose of

paracetamol is taken major amount is

metabolized by glucuronid e and

sulfate conjugation

Minor amount of highly reactive

quinones/epoxidesare formed

They combine with Glutathione

Converted to harmless products

NO Tissue damage

When large amount of drug is

taken(poisoning)

Large number of highly reactive

quinones/epoxidesare formed

Glutathione supply falls short.

Toxic intermediates are formed within tissue constituents

Tissue damage

NAC SUPPLIES

GLUTATHIONE

S

so detoxifies toxic

metabolites !!

NAC

“MAY”directly

conjugates with

quinones/epoxide.

MAY BE…

NAC has

additional

antioxidant and

antiinflammatory

activity

PERIPHERALLY: PGS sensitize the nerve endings to bradykinin and

histamine

CENTRALLY :

PGs Lower the threshold for central pain

circuits

PAINPCM

blocks..

7

REDUCES

THE

INTENSITY

OF PAIN

ANALGESIC ACTIVITY

Hypothalamus contains thermoregulatory centre

Maintains balance between heat production and heat

loss

It regulates heat dissipating mechanisms

When there is tissue

damage/inflamation/AG:A

B reaction/infec

tion

Neutrophilreleases IL-1

Stimulates COX-2

enzymes

Increased PGE2

synthesis in hypothalamus

PGE2 has two mechanisms :

1. Increases heat production.

2.shuts down HEAT LOSING MECHANISM

Raised body temperature FEVER

NSAIDS inhibits

PGE2 synthesis and

reduces fever

ANTIPYRETIC ACTIVITY

Normally hypothalamus is adjusted to a set

point

When temperatures is elevated beyond

level

Hypothalamus activates heat

losing mechanisms like sweating and

vasodilatation

So temperature is normalized

This set point it elevated in

FEVER

ANTIPYRETIC ACTIVITY

direct effects on heat-

regulating centres of the

hypothalamus

Sweating and

vasodilation,

heat dissipation

IBUPROFEN

WHAT IS IBUPROFEN?

Reduces:

• fever,

• pain

• inflammation

Caused by:

many conditions such as headache, toothache, back pain, arthritis, menstrual cramps, or minor injury

BRAND NAMES

Brufen®;

Calprofen®;

Nurofen®;

Orbifen®;

Fenbid®

PREPARATIONS

-Tablets:

- 100, 200, 400, 600, and 800 mg;

Suspension:

100 mg/5 ml and 40 mg/ml

-Chewable tablets:

50 and 100 mg;

ALSO AVAILABLE AS:

capsules,

granules,

oral liquid medicine,

modified-release tablets,

orodispersible (melt in the

mouth) tablets

local gel

USUAL ADULT DOSE FOR PAIN:

Oral: Mild to moderate pain:

200 to 400 mg orally every 4

to 6 hours as needed. Doses

greater than 400 mg have not

been proven to provide

greater efficacy

IV: (Patients should be well hydrated

before IV ibuprofen administration):

Pain: 400 to 800 mg intravenously

over 30 minutes every 6 hours as

needed.

USUAL ADULT ANTI-

INFLAMMATORY DOSE

for Osteoarthritis:

Initial dose: 400 to 800 mg

orally every 6 to 8 hours.

Maintenance dose: May be

increased to a maximum

daily dose of 3200 mg based

on patient response and

tolerance.

for Rheumatoid Arthritis:

Initial dose: 400 to 800 mg

orally every 6 to 8 hours.

Maintenance dose: May be

increased to a maximum

daily dose of 3200 mg based

on patient response and

tolerance.

REFERENCES

http://www.drugs.com/ibuprofen.htmlhttp://www.patient.co.uk/medicine/ibuprofen-for-pain-and-inflammationhttp://www.spine-health.com/treatment/pain-medication/nsaids-non-steroidal-anti-inflammatory-drugshttp://www.medicinenet.com/ibuprofen/article.htmhttp://www.medicinenet.com/acetaminophen/article.

htm

https://www=mechanism+of+action+of+paracetamol&tbm=isch&imgdiihttp://www.ncbi.nlm.nih.gov/pubmed/15662292