LYSIMED

Indications

• Pain relief
• Fever reduction
• Inflammation control
• Cardiovascular event prevention
• Acute myocardial infarction

Mechanism of action

Aspirin exerts its effects primarily through the inhibition of cyclooxygenase (COX) enzymes, specifically COX-1 and COX-2. This inhibition leads to a decrease in the synthesis of prostaglandins and thromboxanes, which are mediators of inflammation, pain, and platelet aggregation. The antiplatelet effect is particularly significant due to the irreversible inhibition of COX-1 in platelets, resulting in reduced thromboxane A2 production and thus decreased platelet aggregation.

Pharmacodynamics

The pharmacodynamics of acetylsalicylate involves its ability to modulate the production of inflammatory mediators and to exert analgesic effects. The onset of action for analgesia can occur within 30 minutes, while its peak effects are observed within 1-2 hours. Aspirin's antipyretic effects are also attributed to its action on the hypothalamus, leading to vasodilation and increased heat loss. The drug's antiplatelet activity can last for the lifespan of the platelet (approximately 7-10 days) due to its irreversible action.

Pharmacokinetics

Aspirin is rapidly absorbed from the gastrointestinal tract, with peak plasma concentrations typically reached within 1-2 hours after oral administration. It is extensively metabolized in the liver via hydrolysis to salicylic acid, which is the active metabolite responsible for many of aspirin's effects. The elimination half-life varies depending on the dose but is generally around 15-20 minutes for aspirin and 2-3 hours for salicylic acid. Aspirin is eliminated primarily through renal excretion, and its pharmacokinetics can be influenced by factors such as pH and urine flow.

Contra-indications

• Active peptic ulcer disease
• History of gastrointestinal bleeding
• Severe hepatic impairment
• Severe renal impairment
• Hypersensitivity to aspirin or other NSAIDs
• Children and adolescents with viral infections (risk of Reye's syndrome)

Adverse effects

• Gastrointestinal irritation
• Nausea
• Vomiting
• Gastrointestinal bleeding
• Tinnitus
• Allergic reactions (including asthma)
• Renal impairment
• Hepatic impairment
• Reye's syndrome in children

Interactions

• Anticoagulants (increased risk of bleeding)
• Other NSAIDs (increased risk of adverse effects)
• Methotrexate (increased toxicity)
• Selective serotonin reuptake inhibitors (SSRIs) (increased risk of bleeding)
• Alcohol (increased risk of gastrointestinal bleeding)

Precautions

• Use with caution in patients with asthma or allergic conditions
• Monitor for signs of gastrointestinal bleeding
• Caution in patients with pre-existing renal or hepatic conditions
• Use with caution in elderly patients due to increased risk of adverse effects

Pregnancy

Use in pregnancy is not recommended, particularly in the third trimester due to potential risk of bleeding.

Breast-feeding

Aspirin is excreted in breast milk; caution is advised when used during breastfeeding.

Storage

Store at room temperature, away from moisture and direct light. Keep out of reach of children.

Formulations

• Tablets
• Enteric-coated tablets
• Effervescent tablets
• Suppositories

Indications

• Herpes simplex virus infections
• Lysine deficiency

Dosage

Children: Refer to the BNF for Children for specific dosage recommendations.

Adults: Refer to the BNF for specific dosage recommendations.

Mechanism of action

Lysine inhibits the viral replication of the herpes simplex virus by altering the amino acid ratio in the tissue culture media. A higher concentration of L-lysine compared to L-arginine has been shown to reduce viral growth and cytopathogenicity. Additionally, lysine facilitates calcium absorption from the small intestine and is involved in protein synthesis through its role in the tRNA charging process, linking amino acids to their corresponding tRNA for translation.

Pharmacodynamics

Lysine ensures adequate calcium absorption and is involved in the formation of collagen, essential for bone, cartilage, and connective tissues. It aids in the production of various biological molecules, including antibodies, hormones, and enzymes. Deficiency in lysine can manifest as tiredness, inability to concentrate, irritability, and other health issues.

Pharmacokinetics

Lysine is absorbed in the small intestine and is transported in the bloodstream to various tissues, where it participates in protein synthesis and other metabolic processes. The metabolism of lysine involves its degradation and utilization in various biosynthetic pathways.

Adverse effects

• Gastrointestinal upset
• Diarrhea
• Nausea
• Abdominal pain

Precautions

• Use with caution in individuals with kidney disease
• Consult a healthcare professional before use if pregnant or breastfeeding

Pregnancy

Safety in pregnancy has not been established. Consult a healthcare professional before use.

Breast-feeding

Lysine is generally considered safe in breastfeeding, but consult a healthcare professional before use.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Oral tablet
• Oral capsule
• Powder for oral solution

Mechanism of action

Proteins of the herpes simplex virus are rich in L-arginine, and tissue culture studies indicate an enhancing effect on viral replication when the amino acid ratio of L-arginine to lysine is high in the tissue culture media. When the ratio of L-lysine to L-arginine is high, viral replication and the cytopathogenicity of herpes simplex virus have been found to be inhibited. L-lysine may facilitate the absorption of calcium from the small intestine. Amino acids are selected for protein synthesis by binding with transfer RNA (tRNA) in the cell cytoplasm. The information on the amino acid sequence of each individual protein is contained in the sequence of nucleotides in the messenger RNA (mRNA) molecules, which are synthesized in the nucleus from regions of DNA by the process of transcription. The mRNA molecules then interact with various tRNA molecules attached to specific amino acids in the cytoplasm to synthesize the specific protein by linking together individual amino acids; this process, known as translation, is regulated by amino acids (e.g., leucine), and hormones. Which specific proteins are expressed in any particular cell and the relative rates at which the different cellular proteins are synthesized, are determined by the relative abundances of the different mRNAs and the availability of specific tRNA-amino acid combinations, and hence by the rate of transcription and the stability of the messages. From a nutritional and metabolic point of view, it is important to recognize that protein synthesis is a continuing process that takes place in most cells of the body. In a steady state, when neither net growth nor protein loss is occurring, protein synthesis is balanced by an equal amount of protein degradation. The major consequence of inadequate protein intakes, or diets low or lacking in specific indispensable amino acids relative to other amino acids (often termed limiting amino acids), is a shift in this balance so that rates of synthesis of some body proteins decrease while protein degradation continues, thus providing an endogenous source of those amino acids most in need. /Amino acids/ The mechanism of intracellular protein degradation, by which protein is hydrolyzed to free amino acids, is more complex and is not as well characterized at the mechanistic level as that of synthesis. A wide variety of different enzymes that are capable of splitting peptide bonds are present in cells. However, the bulk of cellular proteolysis seems to be shared between two multienzyme systems: the lysosomal and proteasomal systems. The lysosome is a membrane-enclosed vesicle inside the cell that contains a variety of proteolytic enzymes and operates mostly at acid pH. Volumes of the cytoplasm are engulfed (autophagy) and are then subjected to the action of the protease enzymes at high concentration. This system is thought to be relatively unselective in most cases, although it can also degrade specific intracellular proteins. The system is highly regulated by hormones such as insulin and glucocorticoids, and by amino acids. The second system is the ATP-dependent ubiquitin-proteasome system, which is present in the cytoplasm. The first step is to join molecules of ubiquitin, a basic 76-amino acid peptide, to lysine residues in the target protein. Several enzymes are involved in this process, which selectively targets proteins for degradation by a second component, the proteasome. /Amino acids/

Pharmacodynamics

Insures the adequate absorption of calcium; helps form collagen ( which makes up bone cartilage & connective tissues); aids in the production of antibodies, hormones & enzymes. Recent studies have shown that Lysine may be effective against herpes by improving the balance of nutrients that reduce viral growth. A deficiency may result in tiredness, inability to concentrate, irritability, bloodshot eyes, retarded growth, hair loss, anemia & reproductive problems.