CNS Pharmacology - Pharmacology MCQ ACEM, Top Questions & Answers. Rated A+

CNS Pharmacology - Pharmacology MCQ ACEM, Top Questions & Answers. Rated A+ Which of the following agents has a pure beta agonist effect in the circulation? 1. Isoprenaline 2. Dopamine 3. Adrenaline 4. Noradrenaline - -1. Isoprenaline Isoprenaline is a pure β-receptor agonist and a potent vasodilator. Dopamine acts on D1 receptors (vasodilation) at higher doses it affects α- and β-receptors. Adrenaline acts on β1, β2 and α1 receptors depending on the dose. Noradrenalin is a potent α- and β1-receptor agonist. Which of the following statements regarding Carbamazepine is CORRECT? 1. It is an enzyme inhibitor 2. Overdose causes seizures 3. Sodium Valproate increases Carbamazepine clearance 4. It metabolizes to non-active metabolites. - -2. Overdose causes seizures CBZ is both enzyme substrate and inducer. Overdose MAY cause convulsions. CBZ may in crease clearance of Phenytoin, VA, Clonazepam, Primidone. The SE include: diplopia, ataxia, drowsiness, aplastic anaemia, agranulocytosis, skin reactions, occasional hyponatraemia and DI. VA DECREASES CBZ clearance. CBZ is COMPLETELY metabolized. Some metabolites have ANTISEIZURE activity. Regarding L-dopa, which of the following statements is CORRECT? 1. It is a precursor to dopamine 2. It has a half life of 5 hours 3. It causes a negative Coombs test. 4. 25% of the oral dose reaches the brain - -1. It is a precursor to Dopamine Levodopa is a levo-rotating isomer of Dopa - the PRECURSOR of Dopamine. The plasma half-life is 1-3hrs. Levodopa can cause POSITIVE COOMB's test. Only 1-3% reaches brain. The rest is metabolized extracranially. Regarding Ergotamine, which of the following statements is INCORRECT? 1. It causes vasoconstriction 2. It can be given parenterally 3. It works well in the early treatment of acute migraine 4. It causes GI haemmorhage - -Ergotamine can be administered PO, PR, INH and IM. Ergot derivatives are highly specific for migraine pain. They are not analgesic for any other condition. The vasoconstriction (partial agonist effects at α-receptors and some as a result of effects at 5-HT receptors) produced by Ergotamine is long lasting and cumulative. The direct receptor stimulation thus prevents vasodilatation and stretching of the pain endings. The most toxic effects of the ergot derivatives are GIT disturbances (diarrhoea, nausea and vomiting). There have been reports of bowel infarction/ischaemia due to vasoconstriction in the gut. GIT haemorrhage DOES NOT occur. Regarding drugs that are used to treat glaucoma, which is the CORRECT pairing of drug-mechanism of action? 1. Timolol - ciliary muscle contraction 2. Pilocarpine -