Diflunisal, Mechanism of action, Adverse effects Explaining “Why Diflunisal is avoided in case of geriatric patients”

1. Gono Bishwabidyalay
Nolam, Saver, Dhaka
8th
Semester
Homework on: Clinical Pharmacy & Pharmacology-II
(Pharm 4803)
Topic: Diflunisal in geriatric patient
Submitted To:
A.F.M Mahmudul Islam
Lecturer
Department of pharmacy, GB
Submitted By:
Md. Nazmul Islam Tanmoy
Class Roll: 74
Exam Roll: 2064
Batch: 32nd
Semester: 8th
Department of pharmacy, GB.
Submission date: 15th
June 2021

2. Diflunisal
Diflunisal is a salicylic acid derivative with analgesic and anti-
inflammatory activity. (Non-selective NSAID)
It was developed by Merck Sharp & Dohme in 1971, as MK647, after
showing promise in a research project studying more potent chemical
analogs of aspirin
Formula: C13H8F2O3
Molar mass: 250.198 g/mol
Elimination half-life: 8 to 12 hours
Metabolism: Hepatic (liver cell)
Mechanism of action
Like all NSAIDs, diflunisal acts by inhibiting the production of
prostaglandins, hormones which are involved in inflammation and pain.
Diflunisal also has an antipyretic effect, but this is not a recommended use
of the drug.

3. From above mechanism it is seen that:
• COX-1 Prostaglandins are beneficial because they help in: -
1. Cytoprotecting gastroduodenal mucosa (housekeeping)
2. Regulation of renal blood flow.
3. Platelet aggregation.
Whereas
• COX-2 Prostaglandins are harmful because they mediate-
1. Fever
2. Pain
3. Inflammation
4. Inflammatory stimuli
Adverse effects:
In general: may cause;
• vomiting.
• diarrhea.
• constipation.
• gas.
• headache.
• dizziness.
• ringing in the ears.
• problems with vision.

4. In geriatric: The elderly are at increased risk for serious;
• Stomach/intestinal bleeding.
• Ulcers.
Explain; “Why Diflunisal is avoided in case of geriatric patient?”
Answer: Diflunisal is a non-selective NSAID, acts by inhibiting the
production of prostaglandins (both COX1 & COX2).
Diflunisal is also metabolized by liver cells. As known with age the size
of live decreases as well as it’s function. Causing increase in plasma
concentration. Thus, result in a further inhibition of prostaglandins
production. But only COX2 is responsible for pain, inflammation &
fever. Whereas COX1 is helpful in cytoprotecting gastroduodenal
mucosa. Inhibition of COX1 prostaglandin leads to stomach or intestinal
bleeding and ulceration. Thus, Diflunisal is avoided in geriatric patients.
Simplified by flow chart below:
With age decrease liver size and function.
Decrease in Diflunisal metabolism
increase in Diflunisal plasma concentration
Further inhibition of prostaglandin
production

5. Decrease in both COX 1&2 prostaglandin
Leading to unprotected gastroduodenal
mucosa.
Causing ulceration and stomach/intestinal
bleeding.