Question

a. Alice is 27-year old female who is five months pregnant. She is undergoing a dermatological procedure requiring local anaesthesia. Her medical history reports the following: allergic to eggs; taking ranitidine for gastric reflux; taking pyridoxine and doxylamine for nausea; history of scoline apnoea, thrombocytopaenia, and gestational diabetes. Her doctor has decided to use tetracaine with felypressin. Discuss the appropriateness of the anaesthetic combination.

b. During a routine check-up at her obstetrician, Alice is made aware that her blood pressure is 145/98 mm/Hg. Follow-up measurements are done, and her blood pressure remains high. Her doctor wishes to prescribe either carvedilol, valsartan, hydralazine, or α-methyldopa as an anti-hypertensive. Given her presentation, i) suggest an appropriate anti-hypertensive to use from those mentioned, ii) justify your selection by referring to the inappropriateness of the other options, and iii) explain how your suggested drug reduces blood pressure.

Answer 1

a.

Tetracaine

Tetracaine, also known as amethocaine, is a local anesthetic used to numb the eyes, nose, or throat. It may also be applied to the skin before starting an intravenous to decrease pain from the procedure. Typically it is applied as a liquid to the area.

Tetracaine is an ester-type anesthetic and produces local anesthesia by blocking the sodium ion channels involved in initiation and conduction of neuronal impulses.

Tetracaine is classified as a pregnancy category C drug .

Felypressin

It is a non-catecholamine vasoconstrictor used in local anaesthetic injections for dental use, and is an ingredient of preparations that have been used for treatment of pain and inflammation of the mouth.

Felypressin is a synthetic analog of lypressin or vasopressin with a greater vasoconstrictor activity than antidiuretic action. It is used primarily as a hemostatic.

Felypressin binds to the vasopressin receptor V1a. This causes contraction of the smooth muscle in the vascular bed, especially capillaries, small arterioles and venules.

Octapressin (Felypressin) is contraindicated during pregnancy as its similarity in structure to oxytocin (the hormone responsible for labour) can result in some contraction of the uterus.

b.

Carvedilol

Carvedilol is a medication used to treat high blood pressure, congestive heart failure, and left ventricular dysfunction in people who are otherwise stable. For high blood pressure, it is generally a second-line treatment.

This drug works by blocking the action of certain natural substances in your body, such as epinephrine, on the heart and blood vessels. This effect lowers your heart rate, blood pressure, and strain on your heart. Carvedilol belongs to a class of drugs known as alpha and beta blockers.

Valsartan

Valsartan is used to treat high blood pressure and heart failure. It is also used to improve the chance of living longer after a heart attack. Valsartan belongs to a class of drugs called angiotensin receptor blockers (ARBs). It works by relaxing blood vessels so that blood can flow more easily. Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems.

This medication is not recommended for use during pregnancy. It may harm an unborn baby.

Hydralazine

Hydralazine is used with or without other medications to treat high blood pressure. Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. Hydralazine is called a vasodilator. It works by relaxing blood vessels so blood can flow through the body more easily.

During pregnancy, this medication should be used only when clearly needed. Before having surgery, tell your doctor that you are taking this medication.

Methyldopa

Methyldopa, is a medication used for high blood pressure. It is one of the preferred treatments for high blood pressure in pregnancy.

Methyldopa is in the alpha-2 adrenergic receptor agonist family of medication. It works by stimulating the brain to decrease the activity of the sympathetic nervous system.

Methyldopa is used in the clinical treatment of the following disorders:

• Hypertension (or high blood pressure)
• Gestational hypertension (or pregnancy-induced hypertension) and pre-eclampsia