Context-sensitive half-time drugs

Drugs which have a context-sensitive half-time which increases with time include

(a) remifentanil

(b) alfentanil

(c) fentanyl

(d) propofol

(e) morphine

Omeprazole

Omeprazole

(a) is a pro-drug

(b) acts by blocking histamine (H2) receptors

(c) is longer acting than cimetidine

(d) has a rapid onset of action

(e) is effective in Zollinger–Ellison syndrome

Doxapram

Doxapram

(a) acts by stimulating peripheral chemoreceptors

(b) is contraindicated in epilepsy

(c) interacts with aminophylline

(d) reduces systolic arterial blood pressure

(e) is a competitive antagonist at the mu receptor

Intravenous mannitol

Intravenous mannitol

(a) is a polyhydric alcohol

(b) is used as a fuel substrate for most cells in the body

(c) extravasations can cause tissue necrosis

(d) causes haemolysis

(e) can cause a delayed increase in cranial pressure

Adenosine

Adenosine

(a) is used to reduce atrioventricular conduction in the treatment of supraventricular  achyarrhythmias

(b) may cause bronchospasm

(c) has a long elimination half-time

(d) is a potent coronary vasodilator

(e) is contraindicated in heart block

Epinephrine

 Injection of intramuscular or intravenous epinephrine causes

(a) increased pulmonary artery systolic pressure

(b) increased pulmonary blood flow

(c) increased pulmonary artery wedge pressure

(d) no change in pulmonary artery pressure

(e) an increase in diastolic blood pressure

Angiotensin Converting Enzyme Inhibitors (ACEI)

Angiotensin converting enzyme inhibitors (ACEI)

(a) reduce arteriolar tone more than venous tone

(b) cause renal impairment in patients with renal artery stenosis

(c) cause troublesome cough

(d) are used to treat pregnancy-induced hypertension

(e) cause hypokalaemia