Review of Pharmacology - 9E (2015)

Review of Pharmacology
52. Ans. (c) Ropinirole (Ref: KDT 6/e p472)
53. Ans. (d) To increase crossing of L-Dopa through BBB (Ref: KDT 6/e p418-419)
54. Ans. (d) Piracetam (Ref: KDT 6/e p473)
Nootropic drugs are those that enhance memory. Piracetam is used for this function in patients with head injury.
55. Ans. (a) Centrally acting reversible anticholinesterase (Ref: KDT 6/e p102)
56. Ans. (a) Entacapone (Ref: KDT 6/e p421)
57. Ans. (c) COMT inhibitors prolong the action of L-dopa (Ref: KDT 6/e p421)
58. Ans (a) Amantadine (Ref: KDT 6/e p421)
59. Ans (a) Riluzole (Ref: KDT 6/e p464-465)
60. Ans. (c) Decrease in antidiuretic hormone (Ref: KDT 7/e p416)
• Carbamazepine like other antiepileptic drugs is teratogenic.
• It can cause neurotoxicity manifested as dizziness, sedation, vertigo, diplopia and ataxia
• It can result in hypersensitivity reactions like rash, photosensitivity, hepatitis and rarely agranulocytosis
• It increases the release of ADH from the hypothalamus and thus can result in dilutional hyponatremia particularly
in elderly people.
Central Nervous System
61. Ans. (a) Levetiracetam (Ref: KDT 7/e p421)
• Levetiracetam, lamotrigine, valproate and topiramate are useful in myoclonic epilepsy. Valproate should be avoided
in pregnancy.
• Vigabatrin has no role in this condition whereas carbamazepine and phenytoin are contra-indicated in myoclonic
epilepsy.
62. Ans. (d) Lamotrigine mainly acts by causing GABA mediated CI- channel opening (Ref: Goodman Gilman 12th/600)
Lamotrigine mainly acts by inhibiting Na + and prolonging their recovery from inactivated state. It can also increase GABAergic
activity, decrease glutamatergic activity and block ca 2+ channels.
63. Ans. (d) Oxcarbazepine (Ref: Harrison 18th/3262)
• Carbamazepine and oxcarbazepine (related drug), phenytoin, lamotrigine and topiramate are currently the
drugs of choice approved for the initial treatment of partial seizures, including those that secondarily generalize.
Overall they have very similar efficacy, but differences in pharmacokinetics and toxicity are the main
determinants for use in a given patient.
• Oxcarbazepine has the advantage of being metabolized in a way that avoids an intermediate metabolite associated
with some of the side effects of carbamazepine. Oxcarbazepine also has fewer drug interactions than
carbamazepine.
64. Ans. (a) Depression of deep tendon reflexes (Ref: Drug Facts and Comparisons 2010/127, Williams Obstetrics/737)
• Knee jerk (patellar reflex) starts diminishing at plasma magnesium concentration of 4mEq/L and disappears at
10mEq/L, where respiratory paralysis is a potential hazard.
65. Ans. (a) Her decision is wrong, as the risk of teratogenicity was the highest in the first trimester (Ref: Goodman and Gilman
12th/1846)
• Teratogenicity of drugs is maximum in the first trimester during the period of organogenesis.
• Anti-epileptic drugs should not be stopped during pregnancy
• The risk of congenital malformations is more if polytherapy is used as compared to single drugs.
66. Ans. (c) Carbamazepine (Ref: Katzung 11/e p418)
• ‘Carbamazepine and phenytoin can aggravate juvenile myoclonic epilepsy’
Drugs useful for myoclonic seizures are:
372
• Valproic acid (Drug of choice)
• Benzodiazepines
• Zonisamide
• Levetiracetam
• Topiramate
• Lamotrigine
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