A nurse is reviewing the health record of a client who asks about using propranolol to treat hypertension.
The nurse should recognize which of the following conditions is a contraindication for taking propranolol?

Anticoagulant drugs are medicines that prevent blood clots from forming or growing larger.

They do not dissolve existing clots or transport platelets. They work by interfering with different steps of the blood coagulation pathway, which is the process that leads to clot formation.

Choice A is wrong because anticoagulant drugs do not dissolve existing clots.

To dissolve clots, you need fibrinolytic drugs, which break down the fibrin mesh that holds the clots together.

Choice B is wrong because anticoagulant drugs do not transport platelets.

Platelets are blood cells that stick together to form clots.

Anticoagulant drugs may affect the function of platelets, but they do not move them around.

Choice C is wrong because anticoagulant drugs do not act as fibrinolytic agents.

Fibrinolytic agents are drugs that activate plasmin, an enzyme that breaks down fibrin.

Anticoagulant drugs may inhibit the formation of fibrin, but they do not break it down.

Some examples of anticoagulant drugs are warfarin, heparin, and factor Xa inhibitors.

The normal ranges for some blood tests that measure the effects of anticoagulants are:

• Prothrombin time (PT): 11 to 13.5 seconds

• International normalized ratio (INR): 0.8 to 1.2

• Activated partial thromboplastin time (aPTT): 25 to 35 seconds

PT stands for prothrombin time, which is a measure of how long it takes the blood to clot.

INR stands for international normalized ratio, which is a way of standardizing the PT results across different laboratories.

Warfarin is a blood thinner that works by inhibiting the production of vitamin K-dependent clotting factors in the liver.

Therefore, warfarin prolongs the PT and increases the INR.The PT/INR test is used to monitor the effectiveness of warfarin therapy and adjust the dose accordingly.

Choice A is wrong because PTT stands for partial thromboplastin time, which is another measure of blood clotting time, but it reflects the activity of different clotting factors than PT.PTT is used to monitor heparin therapy, not warfarin therapy.

Choice C is wrong because aPTT stands for activated partial thromboplastin time, which is a variation of PTT that uses an activator to speed up the clotting time.Like PTT, aPTT is used to monitor heparin therapy, not warfarin therapy.

Choice D is wrong because ACT stands for activated clotting time, which is a measure of the whole blood clotting time.ACT is used to monitor high-dose heparin therapy during certain procedures, such as cardiac bypass surgery or angioplasty.

The normal ranges for these tests may vary depending on the laboratory and the method used, but generally, they are:

• PT: 10 to 13 seconds

• INR: 0.8 to 1.2 (without warfarin) or 2.0 to 3.0 (with warfarin)

• PTT: 25 to 35 seconds

• aPTT: 30 to 40 seconds

• ACT: 70 to 120 seconds