NEET MDS Lessons
Pharmacology
Thiopental
- A barbiturate that is generally used to induce anesthesia.
- The temporal course of effects from induction to recovery depends almost entirely upon progressive redistribution.
- Metabolic degradation or excretion during anesthesia is negligible, except in the case of methohexital.
- The barbiturates produce minimal analgesia.
- Respiratory depression may be pronounced.
- Cardiac output is reduced while total peripheral resistance is increased.
- It does not sensitize the heart to catecholamines.
- It may cause bronchiospasm, especially in asthmatics.
- It is contraindicated in acute intermittent porphyria.
Ibuprofen
used to relieve the symptoms of arthritis, primary dysmenorrhoea, fever; and as an analgesic, especially where there is an inflammatory component.
Indications
rheumatoid arthritis, osteoarthritis, juvenile rheumatoid arthritis, primary dysmenorrhoea
fever, relief of acute and/or chronic pain states in which there is an inflammatory component
MOA
inhibition of cyclooxygenase (COX); thus inhibiting prostaglandin synthesis.
Uses of NSAIDs
NSAIDs are usually indicated for the treatment of acute or chronic conditions where pain and inflammation are present. Research continues into their potential for prevention of colorectal cancer, and treatment of other conditions, such as cancer and cardiovascular disease.
NSAIDs are generally indicated for the symptomatic relief of the following conditions.
rheumatoid arthritis, osteoarthritis, inflammatory arthropathies (e.g. ankylosing spondylitis, psoriatic arthritis, Reiter's syndrome), acute gout, dysmenorrhoea, metastatic bone pain ,headache and migraine, postoperative pain, mild-to-moderate pain due to inflammation and tissue injury, pyrexia, renal colic
Aspirin, the only NSAID able to irreversibly inhibit COX-1, is also indicated for inhibition of platelet aggregation; an indication useful in the management of arterial thrombosis and prevention of adverse cardiovascular events.
SULPHONAMIDES
Derivative of sulphonilamide (Para-amino Benzene (PABA ) sulphonamide).
Anti-bacterial spectrum
Bacteriostatic to gram + and gram - bacteria. but bactericidal concentrations arce attained in urine. S pyogencs. H influenzae.E coli, few- Staph aureus. gonococci. pneumococci, proteus, shigella and Lymphogranuloma venereum.
Mechanism of action
Inhibits bacterial folate synthetase as they compete with PABA
Less soluble in acid urine and may precipitate to cause crystalluria.
Accumulate in patients with renal failure and can cause toxicity
Classification
Shart Acting (4-8 Hrs) sulphadiazine, sulphamethizole.
Intermediate acting(8-16 Hrs): sulphamethoxazole , sulphaphenazole
Long Acting(l-7days): sulphamethoxypyridazine.
Ultralong Acting(3-8days): sulfaline
Adverse effects
I. nausea, vomiting and epigastric pain
2. crystalluria
3. hypersensitivity-like polyarthritis nodosa. Steven-Johnson Syndrome. photosenstivity
4.hemolysis in G-6PD deficiency
5. kernicterus
They inhibit metabolism of phenytoin. tolbutamide. methotrexate
Therapeutic Use
UTI Meningitis, Streptococcal pharyngitis, Bacillary Dysentery
Use of local anesthetics during pregnancy
Local anesthetics (injectable)
Drug FDA category
Articaine C
Bupivacaine C
Lidocaine B
Mepivacaine C
Prilocaine B
Vasoconstrictors
Epinephrine 1:200,000 or 1:100,000 C (higher doses)
Levonordefrin 1:20,000 Not ranked
Local anesthetics (topical)
Benzocaine C
Lidocaine B
CENTRAL NERVOUS SYSTEM PHARMACOLOGY
Antipsychotic Drugs
1. Phenothiazines
a. Aliphatic derivatives
(1) Chlorpromaxine
b. Piperidine derivatives
(1) Thioridazine
(2) Mesoridazine
c. Piperazine derivatives
(1) Fluphenazine
(2) Perphenazine
(3) Prochlorperazine
(4) Trifluoperazine
2. Haloperidol resembles the piperazine phenothiazines.
3. Thiothixene resembles the piperazine phenothiazines.
4. Others (e.g., loxapine, pimozide).
5. Newer and more atypical antipsychotic drugs:
a. Clozapine
b. Olanzapine
c. Quetiapine
d. Risperidone
e. Ziprasidone
f. Aripiprazole
Antidepressant Drugs
Drug treatment of depression is based on increasing serotonin (5-HT) or NE (or both) at synapses in selective tracts in the brain. This can be accomplished by different mechanisms.
Treatment takes several weeks to reach full clinical efficacy.
1. Tricyclic antidepressants (TCAs)
a. Amitriptyline
b. Desipramine
c. Doxepin
d. Imipramine
e. Protriptyline
2. Selective serotonin reuptake inhibitors (SSRIs)
a. Fluoxetine
b. Paroxetine
c. Sertraline
d. Fluvoxamine
e. Citalopram
3. Monoamine oxidase inhibitors (MAOIs)
a. Tranylcypromine
b. Phenelzine
4. Miscellaneous antidepressants
a. Bupropion
b. Maprotiline
c. Mirtazapine
d. Trazodone
e. St. John’s Wort
Antimania Drugs
These drugs are used to treat manic-depressive illness.
A. Drugs
1. Lithium
2. Carbamazepine
3. Valproic acid
Sedative Hypnotics
1. Benzodiazepines
2. Barbiturates
3. Zolpidem and zaleplon
4. Chloral hydrate
5. Buspirone
6. Other sedatives (e.g., mephenesin, meprobamate, methocarbamol, carisoprodol, cyclobenzaprine)
7. Baclofen
8. Antihistamines (e.g., diphenhydramine)
9. Ethyl alcohol
Antiepileptic Drugs
Phenytoin
Carbamazepine
Phenobarbital
Primidone
Gabapentin
Valproic acid
Ethosuximide
Anti-Parkinson Drugs
a. L-dopa plus carbidopa (Sinemet).
b. Bromocriptine, pergolide, pramipexole, ropinirole.
c. Benztropine, trihexyphenidyl, biperiden, procyclidine.
d. Diphenhydramine.
e. Amantadine.
f. Tolcapone and entacapone.
g. Selegiline.
OXYMETAZOLINE
It is a directly acting sympathomimetic amine used in symptomatic relief in nasal congestion which increases mucosal secretion.
It is used:
- As a nasal decongestant in allergic rhinitis, with or without the addition of antazoline or sodium chromoglycate.
- As an ocular decongestant in allergic conjunctivitis.
Compounds like naphazoline and xylometazoline are relatively selective α2 agonists, which on topical application produce local vasoconstriction.