 Let's continue on and discuss hydrolyzine. Hydrolyzine works by causing an increase in cyclic GMP, which leads to a smooth muscle relaxation. So the increase in cyclic GMP inside of the vasculature causes that smooth muscle to relax. It works specifically on arterioles much better than it does on veins. So what is that going to do? It's going to reduce our afterload on the heart. So remember, preload on the heart is what's coming into the heart and the pressures associated with that. Whereas afterload is what is beyond the heart. So in the arteries and arterioles beyond the heart. So hydrolyzine is going to work in our afterload. So when would hydrolyzine be useful? Well, we can use hydrolyzine for severe hypertension and in heart failure. Anytime we need to reduce that pressure beyond the heart to help increase our ability to contract the heart and get a good pump, then we can use hydrolyzine. What do we see as far as side effects go with hydrolyzine? Well, some of the adverse effects include compensatory tachycardia. So because of this compensatory tachycardia, we don't use hydrolyzine in situations with angina or coronary artery disease. We can also see fluid retention, headaches, angina, once again, we don't use it with angina, and drug-induced lupus. Of note, in relation to the compensatory tachycardia, oftentimes we will add a beta blocker to this medication to help reduce the risk of that reflex or compensatory tachycardia. Hydrolyzine is safe in pregnancy, so it is one of the four drugs that we will often use with pregnant females. Let's talk about what medications we'll use in a situation of a hypertensive emergency. As a reminder, hypertensive emergencies are when we have a severely elevated blood pressure with the acute end organ damage. So we need to decrease the blood pressure because we're having systemic signs of that high blood pressure being seen with the patient. So we need to use IV medication because it needs to be a rapid reduction in that blood pressure. We can titrate that medication very quickly as well if we're not giving enough or if we're giving too much. We cannot do that as easily with oral medications. So when a hypertensive emergency, we're going to use nitropresside or phenol depam. Nitropresside is a short-acting vasodilator. It works both on the arteries and the veins, so that means we're going to affect the preload and the afterload. This works by increasing the cyclic GMP via a direct release of nitric oxide. Adversely, we can see cyanide toxicity with nitropresside, so we need to keep an eye out for that. Our other medication for use in a hypertensive emergency is phenol depam. This is a dopamine D1 receptor agonist. How does it work? It's going to decrease our blood pressure and increase our natural esis. So we see vasodilation of the coronary, peripheral, renal, and splanchnic vessels.