A nurse who is caring for a preschooler should question a prescription for which of the following antibiotics?

When caring for a client receiving heparin by continuous IV infusion for the treatment of venous thrombosis, the nurse should monitor the client's aPTT (Activated Partial Thromboplastin Time) to titrate the heparin dose.

Heparin is an anticoagulant medication used to prevent and treat blood clots. The aPTT is a coagulation test that measures the time it takes for the blood to clot when a specific activator is added. Monitoring the aPTT is a standard method for assessing the anticoagulant effect of heparin and ensuring that the client's blood remains within the desired therapeutic range.

The therapeutic range for aPTT while on heparin therapy varies depending on the indication and the client's condition but is generally maintained at a level that prolongs the clotting time enough to prevent and treat thrombosis while avoiding excessive bleeding risk.

Let's go through the other options:

A. Platelet function assay: While monitoring platelet function is essential for assessing overall hemostasis and platelet function, it is not specifically used for titrating heparin doses. Platelet function assays are more commonly used to assess the function of platelets in the context of platelet disorders or antiplatelet medication therapy.

C. INR (International Normalized Ratio): The INR is used to monitor the effect of vitamin K antagonist anticoagulants, such as warfarin, and is not the appropriate test for monitoring heparin therapy.

D. Amylase: Amylase is an enzyme produced by the pancreas and salivary glands and is not relevant for monitoring heparin therapy. Elevated amylase levels are typically associated with pancreatitis and not related to heparin treatment.

Neostigmine is a medication classified as an acetylcholinesterase inhibitor. It is commonly used to treat myasthenia gravis and to reverse the effects of non-depolarizing neuromuscular blocking agents used during surgery. Adverse reactions to neostigmine are related to its cholinergic effects, which result from increased acetylcholine levels in the body.

Let's go through the options:

A. Hypoactive bowel sounds: Neostigmine can actually increase gastrointestinal motility and may cause increased bowel sounds or even diarrhea, not hypoactive bowel sounds. Therefore, hypoactive bowel sounds are not an adverse reaction to neostigmine.

B. Sweating: Sweating is a cholinergic effect and can be an adverse reaction to neostigmine. Increased sweating is a common sign of cholinergic stimulation.

C. Respiratory distress: Respiratory distress can occur as an adverse reaction to neostigmine, particularly if the client has a history of asthma or other respiratory conditions. Neostigmine can cause bronchoconstriction and excessive secretions, leading to respiratory distress.

D. Urinary retention: Neostigmine is actually used to treat urinary retention by increasing bladder contraction. Therefore, urinary retention is not an adverse reaction to neostigmine.

E. Bradycardia: Bradycardia (slow heart rate) is a significant adverse reaction to neostigmine due to its cholinergic effects on the heart. Increased acetylcholine levels can lead to excessive stimulation of the vagus nerve, resulting in bradycardia.