Anti Parkisonian Drugs Question And Answers

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Anti Parkisonian Drugs Important Notes

Anti Parkinsonian Drugs Parkinsonism

  • It is an extrapyramidal motor disorder
  • Characterized by
    • Rigidity
    • Tremor
    • Hypokinesia
    • Excessive salivation
    • Dementia
  • Mainly occurs due to the degeneration of nigrostriatal neurons which are dopaminergic
  • Dopamine deficiency and cholinergic excess occur in it
  • Drugs used for it are
    • Levodopa – precursor of doapmine
    • Carbidopa and benserazide – prevent decarboxylation of levodopa

Anti Parkinsonian Drugs Long Essays

Question 1. Classify the drugs used in Parkinsonism. Discuss the pharmacology and adverse effects of L-dopa.

Answer:

Anti-parkinsonian drugs:

  • These are drugs that have a therapeutic effect on Parkinsonism.

Anti-Parkisonian Drugs Classification:

1. Drugs affecting the brain’s dopaminergic system.

  • Dopamine precursor – levodopa (L-dopa).
  • Peripheral decarboxylase inhibitors – carbidopa, benserazide.
  • Dopaminergic agonists – bromocriptine, ropinirole.
  • MAO-B inhibitor – selegiline.
  • COMT (Catechol-O-methyl transferase) inhibitor – entacapone, touch.

Anti-Parkisonian Drugs Levodopa (L-Dopa):

  • Levodopa is the precursor of dopamine.

Levodopa Mechanism of action:

Levodopa crosses the blood-brain barrier.
↓
It is taken up by pre-synaptic terminals of dopaminergic
neurons.
↓
Dehydroxylation occurs.
↓
Causes the formation of dopamine.

Levodopa Actions:

1. CNS actions.

  • Causes hypokinesia and rigidity resolution.

2. CVS actions:

  • Causes tachycardia and postural hypotension.

3. CTZ [Chemoreceptor trigger zone]

  • Stimulates CTZ to induce vomiting.

4. Endocrine.

  • It acts on pituitary mamma tropes to inhibit prolactin release.

Read And Learn More: Pharmacology Question and Answers

Levodopa Uses:

  • Effective in idiopathic parkinsonism.

Levodopa Adverse effects:

  • GIT symptoms – nausea, vomiting, anorexia.
  • CVS affects – postural hypotension, tachycardia, palpitation, cardiac arrhythmia, and angina.
  • Alteration in taste sensation.
  • Abnormal movements – Dyskinesia, facial tics, grimacing, tongue thrusting.
  • Behavioral effects – mild anxiety, nightmares, mania, hallucinations.
  • Fluctuations in motor performance.

Anti Parkinsonian Drugs Short Essays

Question 1. Explain why levodopa is given along with carbidopa.

Answer:

Decarboxylase inhibitor i.e., carbidopa prevents the conversion of levodopa to dopamine outside the brain by inhibiting the DOPA decarboxylase enzyme, peripherally.

  • This combination can cross the blood-brain barrier and reaches its site of action in the brain.
  • Other benefits obtained by this combination are:
    • It reduces the dose of levodopa Upton approx 1/4th
    • The plasma half-life of levodopa is prolonged.
    • The systemic concentration of dopamine is reduced.
    • Response to levodopa appears earlier.
    • Side effects like nausea and vomiting are reduced.
    • Cardiac complications are minimized.
    • Pyridoxine does not interfere with the treatment
    • The on-Off effect is minimized.
    • The degree of improvement may be higher.

Anti Parkinsonian Drugs Short Answers

Question 1. Is pyridoxine given with levodopa?

Answer:

Pyridoxine is not given with levodopa because.

  • Pyridoxine enhances the decarboxylation of levodopa.
  • Reduces the drug availability to the CNS.
  • This results in the need for greater doses of levodopa for the same desired result
  • Thus, pyridoxine is not combined with levodopa.

 

Anti Arrythmic Drugs Important Notes

1. Antiarrythmic Drugs Classification

Anti-Arrythmic Drugs Classification

Anti Arrythmic Drugs Short Question And Answers

Question 1. Classification of anti-arrhythmic drugs.

Answer:

Arrhythmic Drugs Classification:

1. Class – 1 – Sodium channel blockers.

  • Prolong repolarization – Quinidine, procainamide,
  • Shorten repolarization – Lignocaine, mexiletine.
  • Little or no repolarization – Propafenone, Flecainide.

2. Class 2 – β blockers.

  • Propranolal, esmolol.

3. Class – 3 – Potassium channel blockers.

  • Amiodarone, Dofetilide.

4. Class – 4 – Calcium channel blockers.

  • Verapamil, diltiazem.

Question 2. Why procainamide is preferred to procaine?

Answer:

Procainamide is a derivative of procaine.

  • It is preferred to procaine because.
  1. It has weak anticholinergic action.
  2. Has antiarrhythmic action, while procaine has only a local anesthetic effect
  3. It is better tolerable.

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