Quiz 24: Diuretics
Nitrates mainly produce effect of vasodilatation on systematic veins and arteries. Nitrates are generally used in two ways. In one way these are used to relieve intense pain during angina attack. In another way nitrates are used prophylactically on regular basis such as daily to prevent angina attacks. This group of drugs has immediate onset of action and short duration. The most common administrating route is sublingual route. These drugs relax the vascular smooth muscles which cause vasodilatation and vasodilation produces a decrease in amount of blood through venous return to the heart and decrease in blood pressure. This results in reduced cardiac work which causes reduced requirement of oxygen by the heart and relieves the pain. The vasodilation is also helpful in relieving vasospasm.
In this case the patient is administrated with Lasix, verapamil, transderm-nitro patch and potassium supplement to improve cardiac condition Potassium supplements are provided to recover the potassium lost due to diuresis effect of diuretics. It does not have any effect on bowel movement. The adverse effects of nitroglycerin or in this case transderm-nitro patch are cutaneous flushing, dizziness, headache, weakness, reflex tachycardia caused by sudden drop in blood pressure and fainting. The common side effects of Lasix are itching, increased muscles cramps, dizziness and diarrhea. Verapamil is calcium channel blocker that is used to treat blood pressure and other arrhythmias related to SA and AV nodes. Common side effects of verapamil are headache, dizziness and constipation. Hence it may be concluded that the constipation may be caused by verapamil.
Nitroglycerin is a drug used to treat angina and coronary artery disease. The effect of the various forms of this drug varies and may last up to 24 hours duration depending on the way it is administered. In the question, the nitroglycerin dosage providing the longest duration of action has been asked. Sublingual nitroglycerin tablet is placed under the tongue and is allowed to dissolve on its own. It is not swallowed. Its effect lasts for approximately 30 minutes. The duration of action is not very long. Therefore, Option (a) is incorrect answer. Nitroglycerin ointment is applied on the chest or abdomen. Its effect lasts for 4-8 hours. The effect lasts for lesser time in comparison to other forms of nitroglycerin dosage. Therefore, Option (b) is incorrect answer. IV nitroglycerin (bolus injection) is given intravenously. Its effect is very short and lasts only till it is infused in the body. Therefore, Option (d) is incorrect answer. Sublingual spray is sprayed under the tongue and its effect lasts for around 30 minutes only. Therefore, Option (e) is incorrect answer. Transdermal nitroglycerin is applied on the torso as an adhesive patch. The drug is slowly released in the body and has a lasting capacity of up to 24 hours. In comparison to all other doses, transdermal application of nitroglycerin has the effect that lasts longest. Therefore, Option is the correct answer.