Fluticasone furoate is a synthetic trifluorinated corticosteroid with potent anti-inflammatory activity. Fluticasone furoate is a anti-allergic agents that is FDA approved for the treatment of symptoms of seasonal and perennial allergic rhinitis, asthma and for reducing exacerbations in patients with chronic obstructive pulmonary disease. Fluticasone furoate has been shown in vitro to exhibit a binding affinity for the human glucocorticoid receptor. The clinical relevance of these findings is unknown. The most common adverse reactions (>1% incidence) included headache, epistaxis, pharyngolaryngeal pain, nasal ulceration, back pain, pyrexia, and cough. Coadministration of ritonavir is not recommended. Use caution with coadministration of other potent CYP3A4 inhibitors, such as ketoconazole.

Felodipine is a long-acting 1,4-dihydropyridine calcium channel blocker (CCB)b. It acts primarily on vascular smooth muscle cells by stabilizing voltage-gated L-type calcium channels in their inactive conformation. By inhibiting the influx of calcium in smooth muscle cells, felodipine prevents calcium-dependent myocyte contraction and vasoconstriction. Felodipine is the most potent CCB in use and is unique in that it exhibits fluorescent activity. In addition to binding to L-type calcium channels, felodipine binds to a number of calcium-binding proteins, exhibits competitive antagonism of the mineralcorticoid receptor, inhibits the activity of calmodulin-dependent cyclic nucleotide phosphodiesterase, and blocks calcium influx through voltage-gated T-type calcium channels. Felodipine is used to treat mild to moderate essential hypertension.

Amiodarone is an antiarrhythmic with mainly class III properties, but it possesses electrophysiologic characteristics of all four Vaughan Williams classes. Like class I drugs, amiodarone blocks sodium channels at rapid pacing frequencies, and like class II drugs, amiodarone exerts a noncompetitive antisympathetic action. In addition to blocking sodium channels, amiodarone blocks myocardial potassium channels, which contributes to slowing of conduction and prolongation of refractoriness. It is indicated for initiation of treatment and prophylaxis of frequently recurring ventricular fibrillation and hemodynamically unstable ventricular tachycardia in patients refractory to other therapy. The most common adverse reactions (1-2%) leading to discontinuation of intravenous amiodarone therapy are hypotension, asystole/cardiac arrest/pulseless electrical activity, VT, and cardiogenic shock. Other important adverse reactions are, torsade de pointes (TdP), congestive heart failure, and liver function test abnormalities. Fluoroquinolones, macrolide antibiotics, and azoles are known to cause QTc prolongation. There have been reports of QTc prolongation, with or without TdP, in patients taking amiodarone when fluoroquinolones, macrolide antibiotics, or azoles were administered concomitantly. Since amiodarone is a substrate for CYP3A and CYP2C8, drugs/substances that inhibit these isoenzymes may decrease the metabolism and increase serum concentration of amiodarone.

Gemfibrozil, a fibric acid antilipemic agent similar to clofibrate, is used to treat hyperlipoproteinemia and as a second-line therapy for type IIb hypercholesterolemia. It acts to reduce triglyceride levels, reduce VLDL levels, reduce LDL levels (moderately), and increase HDL levels (moderately). Gemfibrozil increases the activity of extrahepatic lipoprotein lipase (LL), thereby increasing lipoprotein triglyceride lipolysis. It does so by activating Peroxisome proliferator-activated receptor-alpha (PPARα) 'transcription factor ligand', a receptor that is involved in metabolism of carbohydrates and fats, as well as adipose tissue differentiation. This increase in the synthesis of lipoprotein lipase thereby increases the clearance of triglycerides. Chylomicrons are degraded, VLDLs are converted to LDLs, and LDLs are converted to HDL. This is accompanied by a slight increase in secretion of lipids into the bile and ultimately the intestine. Gemfibrozil also inhibits the synthesis and increases the clearance of apolipoprotein B, a carrier molecule for VLDL. Gemfibrozil is most commonly sold as the brand name, Lopid. Other brand names include Jezil and Gen-Fibro.

Rifampin is an antibiotic that inhibits DNA-dependent RNA polymerase activity in susceptible cells. Specifically, it interacts with bacterial RNA polymerase but does not inhibit the mammalian enzyme. It is bactericidal and has a very broad spectrum of activity against most gram-positive and gram-negative organisms (including Pseudomonas aeruginosa) and specifically Mycobacterium tuberculosis. It is FDA approved for the treatment of tuberculosis, meningococcal carrier state. Healthy subjects who received rifampin 600 mg once daily concomitantly with saquinavir 1000 mg/ritonavir 100 mg twice daily (ritonavir-boosted saquinavir) developed severe hepatocellular toxicity. Rifampin has been reported to substantially decrease the plasma concentrations of the following antiviral drugs: atazanavir, darunavir, fosamprenavir, saquinavir, and tipranavir. These antiviral drugs must not be co-administered with rifampin. Common adverse reactions include heartburn, epigastric distress, anorexia, nausea, vomiting, jaundice, flatulence, cramps.

Lixivaptan is an orally-active, vasopressin 2 receptor antagonist. It is indicated for the treatment of symptomatic hypervolemic and euvolemic hyponatremia, associated with heart failure (HF) and syndrome of inappropriate antidiuretic hormone (SIADH). Adverse events likely to be result of the pharmacologic action of lixivaptan are: constipation, dry mouth, dizziness, insomnia. Grapefruit juice significantly increased the extent of lixivaptan absorption as compared to lixivaptan administered under fasted conditions but not under fed conditions. Lixivaptan Cmax and AUC∞ increased by 2.4-fold and 3.2-fold, respectively, when lixivaptan was administered with ketoconazole (the same in case of Simvastatin).

Milk thistle (Silybum marianum) has been used for centuries for the treatment of liver disorders and as a hepatoprotectant. The primary extract of milk thistle is termed silymarin, a complex mixture that contains a number of structurally-related flavonolignans, the flavonoid, taxifolin, and a number of other constituents. The major flavonolignans present in most extracts are silybin A, silybin B, isosilybin A and isosilybin B, silydianin, silychristin and isosilychristin. Isosilybin A has been identified as the first flavonolignan PPAR-gamma agonist. Isosilybin A, elicited the strongest anti-NF-kappaB and anti-HCV actions. The data suggest that silymarin-derived compounds may influence HCV disease course in some patients. Isosilybin A activates apoptotic machinery in prostate cancer cells via targeting Akt-NF-κB-AR axis; thereby, indicating a promising role for this phytochemical in the management of clinical prostate cancer.

Naftopidil,(R)- is an enantiomer of Naftopidil (NAF), a specific subtype selective α1-adrenoceptor blocker. Racemic Naftopidil is frequently used for the treatment of lower urinary tract symptoms/benign prostatic hyperplasia. No significant differences in pharmacokinetic parameters were observed between R(+)- and S(−)-NAF after intravenous administration. However, mean plasma concentrations of S(−)-NAF were higher than those of R(+)-NAF after intragastric administration. S(−)-NAF reached higher plasma concentrations within shorter times and achieved lower plasma CL within 24 h than R(+)-NAF. S(−)-NAF bioavailability in rats was consistently about two-fold higher than that of R(+)-NAF. The major pathways of S(−)-NAF metabolism in vitro were demethylation and hydroxylation. CYP2C9 played the most important role in the demethylation and hydroxylation of both NAF enantiomers.