Non competitive inhibitors cause decrease in
Vmax.


Non-competitive inhibition


• Inhibitor binds to adjacent site and not the
catalytic site of enzyme
◦ Catalytic property of enzyme is reduced:
decreased Vmax
◦ Affinity of the enzyme is not altered: Km is
unaltered

The therapeutic index is calculated with the
following equation: LD50/ED50.
• LD50 (median lethal dose) or TD50 (median
toxic dose)
◦ Dose of the drug at which 50% of the
experimental animals die
◦ Larger the LD50 safer the drug
• In humans, TD50 is considered
• TD50: dose of drug that causes a toxic
response in 50% of the population
• ED50: (median effective dose)
• Dose of the drug at which 50% of the
experimental animals show the specific or
desired effect
◦ Clinically, the therapeutic range bound by the
dose that produces the minimal therapeutic
effect and the dose that produces the
maximal acceptable adverse effect is more
relevant.

INICET 25 RECALL IN group @doctorusmle

Sham surgery sometimes called placebo
surgery involves an active intervention that
undergoes complete surgery and a "sham
surgery" where the patient undergoes all the
procedures related to the surgery except the
final corrective (therapeutic) step. Though there
are controversies surrounding the use of sham
surgery mainly due to ethical issues, it still can
be considered as a placebo in surgical
intervention.


Options B and D: Physiotherapy and cognitive
behavioral therapy are active interventions with
known effects.


Option A: A placebo should be an inert material
with exactly the same physical appearance,
odor, consistency as the active dosage form. A
herbal medication with no effect known does
not necessarily fit in the exact definition of
placebo.

The baby has features of phocomelia
Thalidomide is associated with phocomelia and
multiple defects in internal organs


• Phocomelia is associated with
underdeveloped limbs and absent pelvic
bones.
◦ Both upper and lower limbs are affected; part
of the limbs may be missing
• Fused fingers and missing thumbs are also
seen

What does the area under curve indicates?

The area between the dotted lines in the graph
shows a therapeutic window. It is the range of
steady-state concentrations of drug that
provides therapeutic efficacy with minimal
toxicity.


Therapeutic window expresses a range of
concentrations at which the likelihood of
efficacy is high and the probability of adverse
effects is low.


The therapeutic index (TI) describes a
relationship between the doses of a drug that
causes lethal or toxic effects with the dose that
causes therapeutic effects. It is also called
therapeutic ratio.


Mathematically, you can calculate TI by
following way:


Therapeutic Index = LDso/ED5o (or) Therapeutic
Index =TDso/ED5o


Where,


◦ LDso (Median Lethal dose) is the minimum
amount of drug that causes adverse effects
in 50% of the population. LDso could also be
replaced with Toxic dose (TD50).
• EDso (Median Effective dose) is the quantity
of a drug that can produce desired
therapeutic effects in 50% of the population.

Correct Answer - B
Ans. is 'b'i.e., Verapamil
◦ Among the given options only verapamil has significant plasma
protein binding (see text of the chapter)

Correct Answer -A
Ans. A. Barbiturates

Ans. is 'a" i.e., Fulminant hepatits
Valproate
• Valproate acts by multiple mechanism :
.. Prolongation of inactivated Na* channel.
Inhibition of T type Ca' current.
3. nhibition of degradation of GABA by GABA transminase
facilitation of GABA mediated CI- channel opening.
• Its most serious adverse effect is fulminant hepatitis especially in
children below 3 years.
• Used during pregnancy, it has produced spina bifida and other
neural tube defects.
• Uses (other than epilepsy) --> mania & bipolar illness, prophylaxis of
migraine, trigeminal neuralgia, tardive dyskinesia.
Adverse effect of Valproate
• Neurological - Ataxia, sedation,tremor
•Systemic- Hepatotoxicity, thromobocytopenia,Gl irritation, weight
gain, transient alopecia, hyperammonemia, pancreatitis,coagulation
disorder.