Desmopressin is a chemical that is similar to Antidiuretic Hormone (ADH), which is found naturally in the body and is produced by the hypothalamus and stored, in the posterior pituitary gland. The main function of ADH is to regulate extracellular fluid volume in the body. ADH secretion is stimulated by angiotensin II, linking it to the renin-angiotensin-aldosterone system (RAAS). ADH stimulates water reabsorption in the kidneys by causing the insertion of aquaporin-2 channels on the apical surface of cells of the distal convoluted tubule and collecting tubules. Desmopressin also causes vasoconstriction through its action on vascular smooth muscle cells of the collecting tubules. It increases urine concentration and decreases urine production. Acetate salt of desmopressin is sold under brand name DDAVP with different formulations: DDAVP Nasal Spray is indicated as antidiuretic replacement therapy in the management of central cranial diabetes insipidus and for management of the temporary polyuria and polydipsia following head trauma or surgery in the pituitary region. It is ineffective for the treatment of nephrogenic diabetes insipidus. DDAVP Injection is indicated for patients with hemophilia A with factor VIII coagulant activity levels greater than 5% and is indicated for patients with mild to moderate classic von Willebrand’s disease (Type I) with factor VIII levels greater than 5%. It was suggested that desmopressin-induced relaxation was mediated by a receptor subtype sharing both V1A and V2 pharmacological profiles.

Sulindac is a nonsteroidal anti-inflammatory agent (NSAIA) of the arylalkanoic acid class that is marketed in the U.S. by Merck as Clinoril. Like other NSAIAs, it may be used in the treatment of acute or chronic inflammatory conditions. Sulindac is a prodrug, derived from sulfinylindene, that is converted in vivo to an active sulfide compound by liver enzymes. The sulfide metabolite then undergoes enterohepatic circulation; it is excreted in the bile and then reabsorbed from the intestine. This is thought to help maintain constant blood levels with reduced gastrointestinal side effects. Some studies have shown sulindac to be relatively less irritating to the stomach than other NSAIA's except for drugs of the cyclooxygenase-2 (COX-2) inhibitor class. The exact mechanism of its NSAIA properties is unknown, but it is thought to act on enzymes COX-1 and COX-2, inhibiting prostaglandin synthesis.

Sulindac is a nonsteroidal anti-inflammatory agent (NSAIA) of the arylalkanoic acid class that is marketed in the U.S. by Merck as Clinoril. Like other NSAIAs, it may be used in the treatment of acute or chronic inflammatory conditions. Sulindac is a prodrug, derived from sulfinylindene, that is converted in vivo to an active sulfide compound by liver enzymes. The sulfide metabolite then undergoes enterohepatic circulation; it is excreted in the bile and then reabsorbed from the intestine. This is thought to help maintain constant blood levels with reduced gastrointestinal side effects. Some studies have shown sulindac to be relatively less irritating to the stomach than other NSAIA's except for drugs of the cyclooxygenase-2 (COX-2) inhibitor class. The exact mechanism of its NSAIA properties is unknown, but it is thought to act on enzymes COX-1 and COX-2, inhibiting prostaglandin synthesis.

Tamoxifen (brand name Nolvadex), is selective estrogen receptor modulators (SERM) with tissue-specific activities for the treatment and prevention of estrogen receptor positive breast cancer. Tamoxifen itself is a prodrug, having relatively little affinity for its target protein, the estrogen receptor (ER). It is metabolized in the liver by the cytochrome P450 isoform CYP2D6 and CYP3A4 into active metabolites such as 4-hydroxytamoxifen (4-OHT) (afimoxifene) and N-desmethyl-4-hydroxytamoxifen (endoxifen) which have 30–100 times more affinity with the ER than tamoxifen itself. These active metabolites compete with estrogen in the body for binding to the ER. In breast tissue, 4-OHT acts as an ER antagonist so that transcription of estrogen-responsive genes is inhibited. Tamoxifen has 7% and 6% of the affinity of estradiol for the ERα and ERβ, respectively, whereas 4-OHT has 178% and 338% of the affinity of estradiol for the ERα and ERβ. The prolonged binding of tamoxifen to the nuclear chromatin of these results in reduced DNA polymerase activity, impaired thymidine utilization, blockade of estradiol uptake, and decreased estrogen response. It is likely that tamoxifen interacts with other coactivators or corepressors in the tissue and binds with different estrogen receptors, ER-alpha or ER-beta, producing both estrogenic and antiestrogenic effects. Tamoxifen is currently used for the treatment of both early and advanced estrogen receptor (ER)-positive (ER+) breast cancer in pre- and post-menopausal women. Additionally, it is the most common hormone treatment for male breast cancer. Patients with variant forms of the gene CYP2D6 (also called simply 2D6) may not receive full benefit from tamoxifen because of too slow metabolism of the tamoxifen prodrug into its active metabolites. Tamoxifen is used as a research tool to trigger tissue-specific gene expression in many conditional expression constructs in genetically modified animals including a version of the Cre-Lox recombination technique. Tamoxifen has been shown to be effective in the treatment of mania in patients with bipolar disorder by blocking protein kinase C (PKC), an enzyme that regulates neuron activity in the brain. Researchers believe PKC is over-active during the mania in bipolar patients.

Tamoxifen (brand name Nolvadex), is selective estrogen receptor modulators (SERM) with tissue-specific activities for the treatment and prevention of estrogen receptor positive breast cancer. Tamoxifen itself is a prodrug, having relatively little affinity for its target protein, the estrogen receptor (ER). It is metabolized in the liver by the cytochrome P450 isoform CYP2D6 and CYP3A4 into active metabolites such as 4-hydroxytamoxifen (4-OHT) (afimoxifene) and N-desmethyl-4-hydroxytamoxifen (endoxifen) which have 30–100 times more affinity with the ER than tamoxifen itself. These active metabolites compete with estrogen in the body for binding to the ER. In breast tissue, 4-OHT acts as an ER antagonist so that transcription of estrogen-responsive genes is inhibited. Tamoxifen has 7% and 6% of the affinity of estradiol for the ERα and ERβ, respectively, whereas 4-OHT has 178% and 338% of the affinity of estradiol for the ERα and ERβ. The prolonged binding of tamoxifen to the nuclear chromatin of these results in reduced DNA polymerase activity, impaired thymidine utilization, blockade of estradiol uptake, and decreased estrogen response. It is likely that tamoxifen interacts with other coactivators or corepressors in the tissue and binds with different estrogen receptors, ER-alpha or ER-beta, producing both estrogenic and antiestrogenic effects. Tamoxifen is currently used for the treatment of both early and advanced estrogen receptor (ER)-positive (ER+) breast cancer in pre- and post-menopausal women. Additionally, it is the most common hormone treatment for male breast cancer. Patients with variant forms of the gene CYP2D6 (also called simply 2D6) may not receive full benefit from tamoxifen because of too slow metabolism of the tamoxifen prodrug into its active metabolites. Tamoxifen is used as a research tool to trigger tissue-specific gene expression in many conditional expression constructs in genetically modified animals including a version of the Cre-Lox recombination technique. Tamoxifen has been shown to be effective in the treatment of mania in patients with bipolar disorder by blocking protein kinase C (PKC), an enzyme that regulates neuron activity in the brain. Researchers believe PKC is over-active during the mania in bipolar patients.

Cimetidine is a histamine H2-receptor antagonist. It reduces basal and nocturnal gastric acid secretion and a reduction in gastric volume, acidity, and amount of gastric acid released in response to stimuli including food, caffeine, insulin, betazole, or pentagastrin. It is used to treat gastrointestinal disorders such as gastric or duodenal ulcer, gastroesophageal reflux disease, and pathological hypersecretory conditions. Cimetidine inhibits many of the isoenzymes of the hepatic CYP450 enzyme system. Other actions of Cimetidine include an increase in gastric bacterial flora such as nitrate-reducing organisms. Cimetidine binds to an H2-receptor located on the basolateral membrane of the gastric parietal cell, blocking histamine effects. This competitive inhibition results in reduced gastric acid secretion and a reduction in gastric volume and acidity.

Tamoxifen (brand name Nolvadex), is selective estrogen receptor modulators (SERM) with tissue-specific activities for the treatment and prevention of estrogen receptor positive breast cancer. Tamoxifen itself is a prodrug, having relatively little affinity for its target protein, the estrogen receptor (ER). It is metabolized in the liver by the cytochrome P450 isoform CYP2D6 and CYP3A4 into active metabolites such as 4-hydroxytamoxifen (4-OHT) (afimoxifene) and N-desmethyl-4-hydroxytamoxifen (endoxifen) which have 30–100 times more affinity with the ER than tamoxifen itself. These active metabolites compete with estrogen in the body for binding to the ER. In breast tissue, 4-OHT acts as an ER antagonist so that transcription of estrogen-responsive genes is inhibited. Tamoxifen has 7% and 6% of the affinity of estradiol for the ERα and ERβ, respectively, whereas 4-OHT has 178% and 338% of the affinity of estradiol for the ERα and ERβ. The prolonged binding of tamoxifen to the nuclear chromatin of these results in reduced DNA polymerase activity, impaired thymidine utilization, blockade of estradiol uptake, and decreased estrogen response. It is likely that tamoxifen interacts with other coactivators or corepressors in the tissue and binds with different estrogen receptors, ER-alpha or ER-beta, producing both estrogenic and antiestrogenic effects. Tamoxifen is currently used for the treatment of both early and advanced estrogen receptor (ER)-positive (ER+) breast cancer in pre- and post-menopausal women. Additionally, it is the most common hormone treatment for male breast cancer. Patients with variant forms of the gene CYP2D6 (also called simply 2D6) may not receive full benefit from tamoxifen because of too slow metabolism of the tamoxifen prodrug into its active metabolites. Tamoxifen is used as a research tool to trigger tissue-specific gene expression in many conditional expression constructs in genetically modified animals including a version of the Cre-Lox recombination technique. Tamoxifen has been shown to be effective in the treatment of mania in patients with bipolar disorder by blocking protein kinase C (PKC), an enzyme that regulates neuron activity in the brain. Researchers believe PKC is over-active during the mania in bipolar patients.

Carbidopa is a competitive inhibitor of aromatic L-amino acid decarboxylase that does not cross the blood-brain barrier, is routinely administered with levodopa (LD) for the treatment of the symptoms of idiopathic Parkinson’s disease (paralysis agitans), postencephalitic parkinsonism, and symptomatic parkinsonism, which may follow injury to the nervous system by carbon monoxide intoxication and/or manganese intoxication. Current evidence indicates that symptoms of Parkinson’s disease are related to depletion of dopamine in the corpus striatum. Administration of dopamine is ineffective in the treatment of Parkinson’s disease apparently because it does not cross the blood-brain barrier. However, levodopa, the metabolic precursor of dopamine, does cross the blood- brain barrier, and presumably is converted to dopamine in the brain. When levodopa is administered orally it is rapidly decarboxylated to dopamine in extracerebral tissues so that only a small portion of a given dose is transported unchanged to the central nervous system. For this reason, large doses of levodopa are required for adequate therapeutic effect and these may often be accompanied by nausea and other adverse reactions, some of which are attributable to dopamine formed in extracerebral tissues. Carbidopa inhibits decarboxylation of peripheral levodopa. Carbidopa has not been demonstrated to have any overt pharmacodynamic actions in the recommended doses.

Carbidopa is a competitive inhibitor of aromatic L-amino acid decarboxylase that does not cross the blood-brain barrier, is routinely administered with levodopa (LD) for the treatment of the symptoms of idiopathic Parkinson’s disease (paralysis agitans), postencephalitic parkinsonism, and symptomatic parkinsonism, which may follow injury to the nervous system by carbon monoxide intoxication and/or manganese intoxication. Current evidence indicates that symptoms of Parkinson’s disease are related to depletion of dopamine in the corpus striatum. Administration of dopamine is ineffective in the treatment of Parkinson’s disease apparently because it does not cross the blood-brain barrier. However, levodopa, the metabolic precursor of dopamine, does cross the blood- brain barrier, and presumably is converted to dopamine in the brain. When levodopa is administered orally it is rapidly decarboxylated to dopamine in extracerebral tissues so that only a small portion of a given dose is transported unchanged to the central nervous system. For this reason, large doses of levodopa are required for adequate therapeutic effect and these may often be accompanied by nausea and other adverse reactions, some of which are attributable to dopamine formed in extracerebral tissues. Carbidopa inhibits decarboxylation of peripheral levodopa. Carbidopa has not been demonstrated to have any overt pharmacodynamic actions in the recommended doses.

Carbidopa is a competitive inhibitor of aromatic L-amino acid decarboxylase that does not cross the blood-brain barrier, is routinely administered with levodopa (LD) for the treatment of the symptoms of idiopathic Parkinson’s disease (paralysis agitans), postencephalitic parkinsonism, and symptomatic parkinsonism, which may follow injury to the nervous system by carbon monoxide intoxication and/or manganese intoxication. Current evidence indicates that symptoms of Parkinson’s disease are related to depletion of dopamine in the corpus striatum. Administration of dopamine is ineffective in the treatment of Parkinson’s disease apparently because it does not cross the blood-brain barrier. However, levodopa, the metabolic precursor of dopamine, does cross the blood- brain barrier, and presumably is converted to dopamine in the brain. When levodopa is administered orally it is rapidly decarboxylated to dopamine in extracerebral tissues so that only a small portion of a given dose is transported unchanged to the central nervous system. For this reason, large doses of levodopa are required for adequate therapeutic effect and these may often be accompanied by nausea and other adverse reactions, some of which are attributable to dopamine formed in extracerebral tissues. Carbidopa inhibits decarboxylation of peripheral levodopa. Carbidopa has not been demonstrated to have any overt pharmacodynamic actions in the recommended doses.