NEXPOL SUSPENSION

Indications

• Pain and inflammation in musculoskeletal disorders
• Mild to moderate pain including dysmenorrhea
• Postoperative analgesia
• Dental pain
• Migraine
• Fever

Dosage

Adults: Initially 300–400 mg 3–4 times a day; increase if necessary up to 600 mg 4 times a day; maintenance 200–400 mg 3 times a day, may be adequate.

Mechanism of action

The exact mechanism of action of ibuprofen is unknown. However, it is considered a non-selective inhibitor of cyclooxygenase (COX), which is involved in the synthesis of prostaglandins and thromboxane. By inhibiting COX-1 and COX-2, ibuprofen decreases the production of prostaglandins that mediate inflammation, pain, and fever, while COX-1 inhibition may lead to gastrointestinal side effects.

Pharmacodynamics

Ibuprofen exerts its analgesic effects through multiple pathways involved in both acute and chronic inflammation. It reduces pain and inflammation by inhibiting the synthesis of prostanoids via COX-1 and COX-2. The pain relief is believed to be mediated through both peripheral effects at the site of injury and central effects within the nervous system, particularly affecting pain transmission pathways. Additionally, ibuprofen has antipyretic effects linked to its action on prostanoid synthesis in the hypothalamus.

Pharmacokinetics

Ibuprofen is rapidly absorbed from the gastrointestinal tract, with peak plasma concentrations typically occurring within 1 to 2 hours after oral administration. It is extensively metabolized in the liver, primarily by oxidation, and has an elimination half-life of approximately 2 to 4 hours. The drug is excreted mainly in the urine, with a small proportion eliminated unchanged. Renal impairment may affect ibuprofen clearance, necessitating caution in patients with compromised kidney function.

Contra-indications

• History of hypersensitivity to aspirin or any other NSAID
• Severe renal impairment
• Severe hepatic impairment
• Active peptic ulcer disease
• Caution in patients with asthma, angioedema, urticaria, or rhinitis precipitated by NSAIDs

Adverse effects

• Gastrointestinal ulceration
• Nausea
• Vomiting
• Diarrhea
• Dizziness
• Rash
• Headache
• Tinnitus
• Visual impairment
• Fluid retention
• Increased blood pressure

Interactions

• Increased risk of gastrointestinal bleeding with other NSAIDs or anticoagulants
• May reduce the antihypertensive effect of ACE inhibitors
• May increase serum levels of lithium
• May enhance the effects of other anticoagulants
• Caution with corticosteroids due to increased risk of gastrointestinal side effects

Precautions

• Use with caution in patients with mild to moderate hepatic impairment
• Use with caution in patients with mild to moderate renal impairment
• Monitor for signs of gastrointestinal bleeding
• Avoid use during the third trimester of pregnancy

Pregnancy

Avoid unless the potential benefit outweighs the risk. Avoid during the third trimester due to the risk of closure of the fetal ductus arteriosus and possibly persistent pulmonary hypertension of the newborn.

Breast-feeding

Small amounts are present in milk. Manufacturer advises to avoid unless necessary.

Storage

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

Formulations

• Tablets (200 mg, 400 mg)
• Oral suspension (100 mg/5 mL)
• Gel (5%) for topical application
• Suppositories (various strengths)

Indications

• Mild to moderate pain
• Fever
• Headaches
• Muscle aches
• Arthritis
• Backaches
• Toothaches
• Colds

Dosage

Adults: For adults, the typical dosage is 500 mg to 1 g every 4 to 6 hours, with a maximum daily limit of 4 g. In cases of intravenous administration, the dosage is 15 mg/kg every

Mechanism of action

Paracetamol is thought to exert its analgesic effects by inhibiting cyclo-oxygenase (COX) enzymes, specifically COX-1 and COX-2, which are involved in the synthesis of prostaglandins responsible for pain sensation. Unlike most NSAIDs, paracetamol does not exhibit peripheral anti-inflammatory effects. Its antipyretic action is believed to result from direct action on heat-regulating centers in the brain, leading to peripheral vasodilation and sweating.

Pharmacodynamics

Paracetamol has been shown to have both antipyretic and analgesic effects, lacking any significant anti-inflammatory activity. It does not interfere with platelet aggregation or disrupt hemostasis, making it a safer option for individuals at risk of bleeding. Allergic reactions to paracetamol are rare. The drug does not affect uric acid secretion or acid-base balance when used at recommended doses.

Pharmacokinetics

Paracetamol is rapidly absorbed from the gastrointestinal tract, with peak plasma concentrations typically occurring within 30 to 60 minutes after oral administration. It is primarily metabolized in the liver via conjugation with glucuronide and sulfate, with a minor pathway involving cytochrome P450 enzymes. The elimination half-life ranges from 1 to 4 hours, with renal excretion of metabolites as the primary route of elimination.

Adverse effects

• Nausea and vomiting
• Liver injury
• Renal damage
• Hypersensitivity reactions
• Flushing
• Hypotension
• Anorectal erythema
• Angioedema
• Agranulocytosis
• Thrombocytopenia
• Leukopenia
• Severe cutaneous adverse reactions (SCARs)

Interactions

• Increased risk of methaemoglobinaemia with topical prilocaine
• Increased risk of methaemoglobinaemia with topical anaesthetics
• Increased anticoagulant effect with coumarins
• Increased risk of hepatotoxicity with imatinib
• Decreased exposure with rifampicin
• Decreased exposure with pitolisant

Precautions

• Monitor patients with liver disease or heavy alcohol use for increased risk of hepatotoxicity
• Adjust doses in patients taking enzyme-inducing antiepileptic medications
• Use caution in patients with renal impairment
• Clinical judgement is required for dose adjustment in weight-based dosing

Pregnancy

Paracetamol is generally considered safe to use during pregnancy for pain and fever relief, but should be used at the lowest effective dose for the shortest duration necessary.

Breast-feeding

Paracetamol is excreted in breast milk in small amounts and is considered safe for use while breastfeeding.

Storage

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

Formulations

• Oral tablets (500 mg)
• Oral suspension (120 mg/5 mL, 500 mg/5 mL)
• Rectal suppositories (various strengths)
• Intravenous infusion (various strengths)

Mechanism of action

The exact mechanism of action of ibuprofen is unknown. However, ibuprofen is considered an NSAID and thus it is a non-selective inhibitor of cyclooxygenase, which is an enzyme involved in prostaglandin (mediators of pain and fever) and thromboxane (stimulators of blood clotting) synthesis via the arachidonic acid pathway. Ibuprofen is a non-selective COX inhibitor and hence, it inhibits the activity of both COX-1 and COX-2. The inhibition of COX-2 activity decreases the synthesis of prostaglandins involved in mediating inflammation, pain, fever, and swelling while the inhibition of COX-1 is thought to cause some of the side effects of ibuprofen including GI ulceration. IBUPROFEN AT 25 MG/KG IV INCREASED THE PRIMARY AND TOTAL HEMOSTATIC PLUG FORMATION TIME IN RABBIT EAR CHAMBERS WITH LASER-INDUCED INJURY. THE SAME DOSE INCREASED THE NUMBER OF CUMULATIVE EMBOLI OVER A 10 MINUTE PERIOD AFTER A LASER INJURY TO ARTERIOLES. IN DOGS, DOSES OF 10, 25, AND 50 MG/KG DID NOT ENHANCE THE RELEASE OF (125)I-LABELED FIBRIN DEGRADATION PRODUCTS FROM THE THROMBI AFTER INCUBATION IN PLASMIN, BUT THE LARGEST DOSE SIGNIFICANTLY DECREASED THE THROMBUS WEIGHT 90 AND 180 MINUTES AFTER DRUG ADMINISTRATION. THUS, IBUPROFEN HAD AN INHIBITORY EFFECT ON PLATELET FUNCTION IN VIVO AND IN LARGE DOSES DIMINISHED THE THROMBUS WEIGHT. L-Arginine (L-arg) exhibits multiple biological properties and plays an important role in the regulation of different functions in pathological conditions. Many of these effects could be achieved on this amino acid serving as a substrate for the enzyme nitric oxide synthase (NOS). At the gastrointestinal level, recent reports revealed its protective activities involving a hyperemic response increasing the gastric blood flow. The aim of this study was to characterize the relationship between NOS activity/expression and prostaglandin changes (PGs) in rats gastric mucosa, with L-arg associated resistance to the nonsteroidal anti-inflammatory drug (NSAID) ibuprofen (IBP). The protective effect of oral L-arg (100 mg/kg body wt), administerred together with IBP (100 mg/kg body wt, per os), was evident enough 90 min after drug administration, although a significant protection persisted for more than 6 hr. Pretreatment with N(G)-nitro-L-arginine (L-NNA) (40 mg/kg body wt, intraperitoneally), a competitive inhibitor of constitutive NOS, partly altered the protection afforded by the amino acid. In contrast, no changes could be observed after inducible NOS inhibition [aminoguanidine (AG) 50 mg/Kg body wt, intraperitoneally). L-arg, plus IBP, produced a significant increase of the cyclic GMP (cGMP) response in tissue samples from rat stomach, 90 min and 6 h after drug administration. iNOS activity and mRNA expression were higher in IBP-treated rats, and no differences were observed in inducible responses in the L-arg plus IBP group. No variations in the cNOS activity and expression were found among the different groups of animals assayed. The measurement of mucosal PGE2 content confirmed that biosynthesis of the eicosanoid is maintained by L-arg for over 90 min after IBP, while a total inhibition was observed 6 hr later. The mechanisms of the L-arg protective effect on the damaged induced by IBP could be explained by the different period after drug administration. The early phase is mediated by cyclooxygenase/prostaglandins pathway (COX/PGs) although NO liberated by cNOS and the guanylate cyclase/cGMP pathway could be also relevant. The later phase implicates inhibition of the iNOS/NO response. We previously showed the non-steroidal anti-inflammatory drug (NSAID) ibuprofen suppresses inflammation and amyloid in the APPsw (Tg2576) Tg2576 transgenic mouse. The mechanism for these effects and the impact on behavior are unknown. We now show ibuprofen's effects were not mediated by alterations in amyloid precursor protein (APP) expression or oxidative damage (carbonyls). Six months ibuprofen treatment in Tg+ females caused a decrease in open fie

Pharmacodynamics

Ibuprofen has multiple actions in different inflammatory pathways involved in acute and chronic inflammation. The main effects reported in ibuprofen are related to the control of pain, fever and acute inflammation by the inhibition of the synthesis of prostanoids by COX-1 and COX-2. Pain relief is attributed to peripheral affected regions and central nervous system effects in the pain transmission mediated by the dorsal horn and higher spinothalamic tract. Some reports have tried to link the pain regulation with a possible enhancement on the synthesis of endogenous cannabinoids and action on the NMDA receptors. The effect on pain has been shown to be related to the cortically evoked potentials. The antipyretic effect is reported to be linked to the effect on the prostanoid synthesis due to the fact that the prostanoids are the main signaling mediator of pyresis in the hypothalamic-preoptic region. The use of ibuprofen in dental procedures is attributed to the local inhibition of prostanoid production as well as to anti-oedemic activity and an increase of plasma beta-endorphins. Some reports have suggested a rapid local reduction of the expression of COX-2 in dental pulp derived by the administration of ibuprofen. The administration of ibuprofen in patients with rheumatic diseases has shown to control joint symptoms. Ibuprofen is largely used in OTC products such as an agent for the management of dysmenorrhea which has been proven to reduce the amount of menstrual prostanoids and to produce a reduction in the uterine hypercontractility. As well, it has been reported to reduce significantly the fever and the pain caused by migraines. This effect is thought to be related to the effect on platelet activation and thromboxane A2 production which produces local vascular effects in the affected regions. This effect is viable as ibuprofen can enter in the central nervous system. In the investigational uses of ibuprofen, it has been reported to reduce neurodegeneration when given in low doses over a long time. On the other hand, its use in Parkinson disease is related to the importance of inflammation and oxidative stress in the pathology of this condition. The use of ibuprofen for breast cancer is related to a study that shows a decrease of 50% in the rate of breast cancer.

Mechanism of action

According to its FDA labeling, acetaminophen's exact mechanism of action has not been fully established - despite this, it is often categorized alongside NSAIDs (non-steroidal anti-inflammatory drugs) due to its ability to inhibit the cyclo-oxygenase (COX) pathways. It is thought to exert central actions which ultimately lead to the alleviation of pain symptoms. One theory is that acetaminophen increases the pain threshold by inhibiting two isoforms of cyclo-oxygenase, COX-1 and COX-2, which are involved in prostaglandin (PG) synthesis. Prostaglandins are responsible for eliciting pain sensations. Acetaminophen does not inhibit cyclooxygenase in peripheral tissues and, therefore, has no peripheral anti-inflammatory effects. Though acetylsalicylic acid (aspirin) is an irreversible inhibitor of COX and directly blocks the active site of this enzyme, studies have shown that acetaminophen (paracetamol) blocks COX indirectly. Studies also suggest that acetaminophen selectively blocks a variant type of the COX enzyme that is unique from the known variants COX-1 and COX-2. This enzyme has been referred to as _COX-3_. The antipyretic actions of acetaminophen are likely attributed to direct action on heat-regulating centers in the brain, resulting in peripheral vasodilation, sweating, and loss of body heat. The exact mechanism of action of this drug is not fully understood at this time, but future research may contribute to deeper knowledge. Although further investigation is warranted, the active metabolite of acetaminophen (AM404) was shown to interact with several molecular targets, including the Ca_v3.2 calcium channel, the cannabinoid CB1 receptors, TRPV1 receptors, and Na_v1.8 and Na_v1.7 channels. Acetaminophen produces analgesia and antipyresis by a mechanism similar to that of salicylates. Unlike salicylates, however, acetaminophen does not have uricosuric activity. There is some evidence that acetaminophen has weak anti-inflammatory activity in some nonrheumatoid conditions (e.g., in patients who have had oral surgery). ... Acetaminophen lowers body temperature in patients with fever but rarely lowers normal body temperature. The drug acts on the hypothalamus to produce antipyresis; heat dissipation is increased as a result of vasodilation and increased peripheral blood flow. The effects of acetaminophen on cyclooxygenase activity have not been fully determined. Acetaminophen is a weak, reversible, isoform-nonspecific cyclooxygenase inhibitor at dosages of 1 g daily. The inhibitory effect of acetaminophen on cyclooxygenase-1 is limited, and the drug does not inhibit platelet function. Therapeutic doses of acetaminophen appear to have little effect on cardiovascular and respiratory systems; however, toxic doses may cause circulatory failure and rapid, shallow breathing. Acetaminophen (N-acetyl-p-aminophenol (APAP)) is the most common antipyretic/analgesic medicine worldwide. If APAP is overdosed, its metabolite, N-acetyl-p-benzo-quinoneimine (NAPQI), causes liver damage. However, epidemiological evidence has associated previous use of therapeutic APAP doses with the risk of chronic obstructive pulmonary disease (COPD) and asthma. The transient receptor potential ankyrin-1 (TRPA1) channel is expressed by peptidergic primary sensory neurons. Because NAPQI, like other TRPA1 activators, is an electrophilic molecule, /the researchers/ hypothesized that APAP, via NAPQI, stimulates TRPA1, thus causing airway neurogenic inflammation. NAPQI selectively excites human recombinant and native (neuroblastoma cells) TRPA1. TRPA1 activation by NAPQI releases proinflammatory neuropeptides (substance P and calcitonin gene-related peptide) from sensory nerve terminals in rodent airways, thereby causing neurogenic edema and neutrophilia. Single or repeated administration of therapeutic (15-60 mg/kg) APAP doses to mice produces detectable levels of NAPQI in the lung, and increases neutrophil numbers, myeloperoxidase

Pharmacodynamics

Animal and clinical studies have determined that acetaminophen has both antipyretic and analgesic effects. This drug has been shown to lack anti-inflammatory effects. As opposed to the _salicylate_ drug class, acetaminophen does not disrupt tubular secretion of uric acid and does not affect acid-base balance if taken at the recommended doses. Acetaminophen does not disrupt hemostasis and does not have inhibitory activities against platelet aggregation. Allergic reactions are rare occurrences following acetaminophen use.