NEET MDS Lessons
Pharmacology
Levofloxacin
Levofloxacin is effective against a number of gram-positive and gram-negative bacteria. Because of its broad spectrum of action, levofloxacin is frequently prescribed in hospitals for pulmonary infections
Seizure classification:
based on degree of CNS involvement, involves simple ( Jacksonian; sensory or motor cortex) or complex symptoms (involves temporal lobe)
1. Generalized (whole brain involved):
a. Tonic-clonic:
Grand Mal; ~30% incidence; unconsiousness, tonic contractions (sustained contraction of muscle groups) followed by clonic contractions (alternating contraction/relaxation); happens for ~ 2-3 minutes and people don’t breathe during this time
Drugs: phenytoin, carbamazepine, Phenobarbital, lamotrigine, valproic acid
Status epilepticus: continuous seizures; use diazepam (short duration) or diazepam + phenytoin
b. Absence:
Petit Mal; common in children; frequent, brief lapses of consciousness with or without clonic motor activity; see spike and wave EEg at 3 Hz (probably relates to thalamocorticoreverburating circuit)
Drugs: ethosuximide, lamotrigine, valproic acid
c. Myoclonic: uncommon; isolated clinic jerks associated with bursts of EEG spikes;
Drugs: lamotrigine, valproic acid
d. Atonic/akinetic: drop seizures; uncommon; sudden, brief loss of postural muscle tone
Drugs: valproic acid and lamotrigine
2. Partial: focal
a. Simple: Jacksonian; remain conscious; involves motor or sensory seizures (hot, cold, tingling common)
Drugs: carbamazepine, phenytoin, Phenobarbital, lamotrigine, valproic acid, gabapentin
b. Complex: temporal lobe or psychomotor; produced by abnormal electrical activity in temporal lobe (involves emotional functions)
Symptoms: abnormal psychic, cognitive, and behavioral function; seizures consist of confused/altered behavior with impaired consciousness (may be confused with psychoses like schizophrenia or dementia)
Drugs: carbamazepine, phenytoin, laotrigine, valproic acid, gabapentin
Generalizations: most seizures can’t be cured but can be controlled by regular administration of anticonvulsants (many types require treatment for years to decades); drug treatment can effectively control seizures in ~ 80% of patients
Ketoconazole
synthetic antifungal drug
used for infections such as athlete's foot, ringworm, candidiasis (yeast infection or thrush), jock itch.
Ketoconazole is used to treat eumycetoma, the fungal form of mycetoma.
MOA: Ketoconazole is imidazole structured, and interferes with the fungal synthesis of ergosterol, the main constituent of cell membranes, as well as certain enzymes. It is specific for fungi, as mammalian cell membranes contain no ergosterol.
Sensitive fungi Ketoconazole inhibits growth of dermatophytes and yeast species (such as Candida albicans).
Gentamicin
Gentamicin is a aminoglycoside antibiotic, and can treat many different types of bacterial infections, particularly Gram-negative infection.
Gentamicin works by binding to a site on the bacterial ribosome, causing the genetic code to be misread.
Like all aminoglycosides, gentamicin does not pass the gastro-intestinal tract, so it can only be given intravenously or intramuscularly.
Gentamicin can cause deafness or a loss of equilibrioception in genetically susceptible individuals. These individuals have a normally harmless mutation in their DNA, that allows the gentamicin to affect their cells. The cells of the ear are particularly sensitive to this.
Gentamicin can also be highly nephrotoxic, particularly if multiple doses accumulate over a course of treatment. For this reason gentamicin is usually dosed by body weight. Various formulae exist for calculating gentamicin dosage. Also serum levels of gentamicin are monitored during treatment.
E. Coli has shown some resistance to Gentamicin, despite being gram-negative
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.
Stages of anesthesia
Stage I
Analgesia
Still conscious but drowsy
Stage II
Excitement stage
Loss of consciousness, however, irregular ventilation may be present which affects absorption of inhalation agents.
Reflexes may be exaggerated.
This is a very dangerous stage
Stage III
Surgical anesthesia
Loss of spontaneous movement
Regular, shallow respiration
Relaxation of muscles
Stage IV
Medullary paralysis
Death
Nimesulide
analgesic and antipyretic properties
Nimesulide is a relatively COX-2 selective, non-steroidal anti-inflammatory drug (NSAID) with analgesic and antipyretic properties. Its approved indications are the treatment of acute pain, the symptomatic treatment of osteoarthritis and primary dysmenorrhoea in adolescents and adults above 12 years old.
Banned - not used