Analgesics myocardial infarction

Q86 Patients with a suspected infarction should receive analgesics intravenously as soon as possible. Pain in myocardial infarction may cause adverse haemodynamic effects such as increases in blood pressure and heart rate. 

Morphine is an opioid analgesic that may be used for pain relief in myocardial infarction. However, diamorphine is usually preferred because it causes a lower risk of nausea and hypotension than morphine. 

Acetaminophen is similar to salicylates in that it is a useful analgesic for mild to moderate pain, with equal efficacy to aspirin, and like aspirin, it is antipyretic. However, acetaminophen exerts little if any effects on platelet aggregation and is not antiinflammatory. Thus, it is not useful for patients with arthritis or other inflammatory diseases. It is also not useful as an antithrombotic agent in the prevention of myocardial infarction or transient ischemic attacks. Acetaminophen does not produce the gastric ulceration that can occur with aspirin and is useful in patients who are salicylate sensitive or who have a history of ulcers or other gastric ulcerations. 

Aspirin (acetylsalicylic acid, Figure 7.9) is a derivative of salicyclic acid, which was first used in 1875 as an antipyretic and antirheumatic. The usual dose for mild pain is 300-600 mg orally. In the treatment of rheumatic diseases, larger doses, 5-8 g daily, are often required. Aspirin is rapidly hydrolysed in the plasma, liver and eiythrocytes to salicylate, which is responsible for some, but not all, of the analgesic activity. Both aspirin and salicylate are excreted in the urine. Excretion is facilitated by alkalinisation of the urine. Metabolism is normally very rapid, but the liver enzymes responsible for metabolism are easily saturated and after multiple doses the terminal half-life may increase from the normal 2-3 h to 10 h. A soluble salt, lysine acetylsalicylic acid, with similar pharmacological properties to aspirin, has been used by parenteral administration for postoperative pain. Aspirin in low doses (80-160 mg daily) is widely used in patients with cardiovascular disease to reduce the incidence of myocardial infarction and strokes. The prophylaxis against thromboembolic disease by low-dose aspirin is due to inhibition of COX-1-generated thromboxane A2 production. Because platelets do not form new enzymes, and COX-1 is irreversibly inhibited by aspirin, inhibition of platelet function lasts for the lifetime of a platelet (8-10 days). 

Nagle, R.E. and Pilcher, J. Respiratory and circulatory effects of pentazocine. Review of analgesics used after myocardial infarction, Br. Heart J. 1972, 34, 244-251. 

It is a potent synthetic opiate analgesic that gets completely absorbed from the G1 tract after oral administration and, importantly, it undergoes almost 80% first-pass metabolism. It has been duly established that this drug enhances arterial resistance and the work of the heart (an action very much akin to petazocine ) consequently, it is usually contra indicated in such patients who have a history of acute myocardial infarction. 

Severe pain whicn cannot be alleviated by non-narcotic analgesics or weaker narcotic analgesics. Drug of choice for treating severe pain of myocardial infarction. 

Aspirin Irreversibly inhibits cyclooxygenase. Thus prevents formation of thromboxane A2 and prostaglandins (which induce platelet aggregation). Reduce risk of recurrent transient ischemic attacks or stroke. Reduces risk of myocardial infarction in patients with unstable angina or prior infarction. Also used for antiinflammatory and analgesic purposes. Gl ulceration, bleeding, hemorrhage, salicylism. 

Acute pain is the presence of severe discomfort or an uncomfortable sensation that has a sudden onset and subsides with treatment. For example, a fractured bone causes acute pain since the uncomfortable sensation occurs suddenly when the bone is broken and subsides when the bone is immobilized in a cast. Pain associated with myocardial infarction (heart attack), appendicitis, and kidney stones are also examples of acute pain. Acute pain can be treated with NSAIDs or opioid analgesics. 

Visceral pain is the dull and aching pain caused by stimulating nerve endings in smooth muscle or sympathetically innervated organs. Visceral pain is referred pain. This makes it difficult to localize the source of the pain. Pain of a myocardial infarction (MI) is an example of visceral pain. MI can be described as cmshing chest pain and also described as pain in the left arm or hand and even the shoulder, left back, or the left ear. Visceral pain is best treated with opioid analgesics. 

The client is complaining of severe chest pain radiating down the left arm and is nauseated and diaphoretic. The HCP suspects the client is having a myocardial infarction (Ml) and has ordered morphine sulfate (MS), a narcotic analgesic, for the pain. Which intervention should the nurse implement ... 

An established interaction although information is limited. The delay and reduction in the absorption would seem to limit the value of oral mexiletine during the first few hours after a myocardial infarction, particularly if opioid analgesics are used. The manufacturer suggests that a higher load-... 

Morphine has hypotensive effects, increasing peripheral vascular capacity and decreasing blood pressure, which may be mediated through adenosine. For this reason, as well as its analgesic properties, intravenous morphine has been given for myocardial infarction, although it is not a part of the current standard of treatment. 

---