NEET MDS Lessons
Pharmacology
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).
Classification
1. Natural Alkaloids of Opium
Phenanthrenes -> morphine, codeine, thebaine
Benzylisoquinolines -> papaverine, noscapine
2. Semi-synthetic Derivatives
diacetylmorphine (heroin) hydromorphone, oxymorphone hydrocodone, oxycodone
3. Synthetic Derivatives
phenylpiperidines pethidine, fentanyl, alfentanyl, sufentnyl
benzmorphans pentazocine, phenazocine, cyclazocine
propionanilides methadone
morphinans levorphanol
Methods of general anesthesia
CIRCLE SYSTEM
*HIGH-FLOW
FRESH GAS FLOW > 3 l/min.
*LOW-FLOW
FGF ok. 1l/min.
*MINIMAL-FLOW
FGF ok. 0,5 l/min.
Antidiarrheal
Antidiarrheal drugs may be given to relieve the symptom (non-specific therapy) or may be given to treat the underlying cause of the symptom (specific therapy).
Ι. Drugs used for the symptomatic (non-specific) treatment of diarrhoea include:
• Opiates and opiate derivatives are the most effective (such as morphine), but it is not used because of potentially serious adverse effects. Other agents, such as diphenoxylate and loperamide, are commonly used.
• Adsorbent – demulcent products such as kaolin – pectin preparation may be included in antidiarrheal preparations. Unfortunately, they may adsorb nutrients and other drugs, including the antidiarrheal agents if given concurrently.
• Anticholinergic agents e.g. atropine is occasionally used to decrease abdominal cramping and pain associated with diarrhoea.
ΙΙ. Specific therapy may include the use of antibacterial agents that are recommended for use in carefully selected cases of bacterial enteritis. For example, severe diarrhoea by salmonella, shigella, campylobacter and clostridia species can be treated by antibiotics (ampicillin, chloramphenicol, co-trimoxazole).
ISOPRENALINE
It is beta-receptor stimulant, which stimulates the heart and causes tachycardia.
It relaxes the smooth muscles particularly the bronchial and GIT. It is mainly used in bronchial asthma, in the treatment of shock and as a cardiac stimulant in heart block.
ORCIPRENALINE
Is a potent β-adrenergic agonist.
Receptor sites in the bronchi and bronchioles are more sensitive to the drug than those in the heart and blood vessels.
AMPHETAMINE
increases the systolic and diastolic blood pressure. Amphetamine is a potent CNS stimulant and causes alertness, insomnia, increased concentration, euphoria or dysphoria and increased work capacity.
Amphetamines are drugs of abuse and can produce behavioural abnormalities and can precipitate psychosis.
PHENYLEPHRINE
It is used as a nasal decongestant and mydriatic agent and also in the treatment of paroxysmal supraventricular tachycardia.
UTERINE RELAXANTS (TOCOLYTICS)
ISOXSUPRINE
Isoxsuprine has a potent inhibitory effect on vascular and uterine smooth muscle and has been used in the treatment of dysmenorrhoea, threatened abortion, premature labour and peripheral vascular diseases.
Clavulanic acid is often combined with amoxicillin to treat certain infections caused by bacteria, including infections of the ears, lungs, sinus, skin, and urinary tract. It works by preventing bacterium that release beta-lactamases from destroying amoxicillin.
Antimania Drugs
MANIC SYMPTOMSMANIC SYMPTOMS
Elevated or irritable mood
Increased activity or psychomotor agitation
Reduced need for sleep
Inflated self esteem or grandiosity
Increased or pressure of speech
Flight of ideas
These drugs are used to treat manic-depressive illness.
1. Lithium
2. Carbamazepine
3. Valproic acid
Mechanisms of action
1. Lithium works inside the cell to block conversion of inositol phosphate to inositol.
2. Carbamazepine blocks sodium channels
3. Valproic acid blocks sodium and calcium channels
PHARMACOKINETICS
Absorbed readily and almost completely from the GI tract; peak concentrations in 1-2 hrs
Lithium toxicity
1. Nausea, diarrhea, convulsions, coma, hyperreflexia, cardiac arrhythmias, hypotension.
2. Thyroid enlargement; increases thyroid stimulating hormone (TSH) secretion; may cause hypothyroidism.
3. Polydipsia, polyuria (lithium inhibits the effect of antidiuretic hormone on the kidney).
Clinical applications concerning lithium
- Patients must be warned against sodium-restricted diets because sodium restriction leads to greater retention of lithium by the kidney.
- Patients must have regular (e.g., monthly) blood checks because the margin of safety is narrow.
Endocrine Effects – Goitre and hypothyroidism commonly
Cardiac Effects:– ECG changes(common) - T-wave flattening/inversion and appearance of U wavesflattening/inversion and appearance of U waves
Li and Pregnancy -1st Trimester:Cardiovascular anomalies of the newborn, especially Ebstein's malformation
- 3rd Trimester: Neonatal goiter, CNS depression, hypotonia ("floppy baby" syndrome)
Drug–drug interactions of lithium
Diuretics and newer nonsteroidal anti-inflammatory drugs (NSAIDs) reduce lithium excretion and may cause lithium toxicity.