Scenario

Scenario

Questions

1. Prior to administering GTN to Leonard, what are the relevant considerations regarding the following;

• The appropriate dose and frequency of administration?

The appropriate dose and frequency of administration is entirely dependent on the physical and pharmacokinetic properties of the drug. For example, slow releasing tablets and drugs with long duration of action may not require frequent dosing. It is called bio-pharmaceutics, an area that is concerned about drug formulations and the nature of their activity. 

• The patient’s vital signs and history (particularly medications)?

The patient’s vital signs are characteristic of cardiovascular disease and should provide a significant lead to the possible cause of the current condition. In addition, Leonard’s past history of various cardiovascular diseases point to that possibility.

1. Explain in point form:

• The mechanism of action of GTN.

Glyceryl Trinitrate releases free nitrite ion that gets oxidized to nitric oxide, which then activates Guanyl Cyclase. Guanyl Cyclase increases the level of cyclic Guanyl Monophosphate in blood, a compound which is a potent relaxant of smooth muscle. This effectively allows smoother blood flow to tissues and peripheral organs (Anthony & Mike 2010).

• The physiological rationale for administering GTN (i.e. what is the intended physiological outcome of administering GTN).

The drug is intended to relieve the chest pain and pressure. These are constitutive symptoms of blockade of blood flow to tissues of the heart. The chest pressure is particularly associated with the blockade of the coronary artery that supplies blood to the heart muscles. Glyceryl Trinitrate would open up these arteries by stimulating smooth muscle relaxation.

• The rationale for the sublingual route of administration of GTN.

Sublingual route of administration is meant to achieve immediate therapy. Drugs that are administered sublingually go into circulation immediately without going through the normal digestive system, which would be slow.

3. Interpret the ECG shown in Figure 1 and provide your provisional diagnosis. What are your immediate transport considerations for Leonard?

There is abnormal sinus rhythm marked by moderate palpitations. The abnormal ECG result is a possible sign of extensive damage to the cardiac muscles. The provisional diagnosis is coronary artery disease.

4.  Explain in point form:

• The mechanism of action of aspirin relevant to this setting.

Aspirin is used in this case for prophylaxis against cardiovascular diseases. It significantly reduces the potential risk of blood vessel occlusion. This is attributed to its inhibition of platelet aggregation. Blood vessel blockades result from deposition of thrombus, which are products of platelet aggregation.

• The physiological rationale for administering aspirin in this setting (i.e. what is the intended physiological outcome of administering aspirin to a person with Leonard’s clinical picture).

It will prevent formation of further clots that may complicate the situation. It should, however, be noted that aspirin does not dissolve preexisting clots.

• Your considerations regarding the suitability/safety of giving Leonard aspirin and the reason(s) for these considerations.

Aspirin has a wide therapeutic window and is not likely to cause toxicity. In fact, it provides synergistic therapy in that it also relieves pain. Aspirin was definitely suitable for the condition.

5. Explain in point form:

• The mechanism of action of Clopidogrel.

This is an oral drug that has potent anti-platelet activity and prevents blood clotting in coronary artery disease. It irreversibly inhibits ADP receptors that are found on the cell membranes of platelets.  

• The physiological rationale for administering Clopidogrel (i.e. what is the intended physiological outcome of administering Clopidogrel).

Just like aspirin, Clopidogrel will prevent formation of further clots that may worsen the situation. Its blockade of the receptor effectively prevents platelet aggregation and the eventual cross-linking with fibrin proteins.

• The implications of administering Clopidogrel prior to coronary angiography.

The clinical situation where it would be inappropriate to administer clopidogrel to Leonard

It is very risky to administer in cases where there is pathological bleeding. It will be advisable to do coronary angiography to ascertain that there is no pathological bleeding before prescribing the drug.