β1-selectivity
Bisoprolol β1-selectivity is especially important in comparison to other nonselective beta blockers. The effects of the drug are limited to areas containing β1 adrenoreceptors, which is mainly the heart and part of the kidney. Bisoprolol, whilst β1 adrenoceptor selective can help patients to avoid certain side-effects associated with non-selective beta-blocker activity at additional adrenoceptors (α1 and β2), it does not signify its superiority in treating beta-blocker indicated cardiac conditions such as heart failure but could prove beneficial to patients with specific comorbidities.Bisoprolol has a higher degree of β1-selectivity compared to atenolol, metoprolol and betaxolol. With a selectivity ranging from being 11-15 times more selective for β1over β2  However nebivolol is approximately 3.5 times more β1-selective. Renin-angiotensin system
Bisoprolol inhibits renin secretion by about 65% and tachycardia by about 30%. Pharmacokinetics
After ingestion, bisoprolol is absorbed and has a high bioavailability of approximately 90% with plasma half-life of 10-12 hours. When being eliminated, the body evenly distributes it (50–50) between kidney excretion and liver biotransformation (then excreted).Bisoprolol has both lipid- and water-soluble properties.The plasma protein binding of bisoprolol is approximately 35%, the volume of distribution is 3.5 L/kg and the total clearance is approximately 15 L/h. Bisoprolol is eliminated from the body in two ways - 50% of the substance is converted in the liver to inactive metabolites, which are then excreted in the kidneys. The remaining 50% is eliminated unchanged via the kidneys. Since elimination is equal in liver and kidney, no dose adjustment is required in patients with hepatic or renal impairment.
Rimantadine (INN, sold under the trade name Flumadine) is an orally administered antiviral drug used to treat, and in rare cases prevent, influenzavirus A infection. When taken within one to two days of developing symptoms, rimantadine can shorten the duration and moderate the severity of influenza. Rimantadine can mitigate symptoms, including fever. Both rimantadine and the similar drug amantadine are derivates of adamantane. Rimantadine is found to be more effective than amantadine because when used the patient displays fewer symptoms. Rimantadine was approved by the Food and Drug Administration (FDA) in 1994. Rimantadine was approved for medical use in 1993. Seasonal H3N2 and 2009 pandemic flu samples tested have shown resistance to rimantadine, and it is no longer recommended to prescribe for treatment of the flu. Medical use
Influenza A
Rimantadine inhibits influenza activity by binding to amino acids in the M2 transmembrane channel and blocking proton transport across the M2 channel. Rimantadine is believed to inhibit influenzas viral replication, possibly by preventing the uncoating of the viruss protective shells, which are the envelope and capsid. The M2 channel is known to be responsible for viral replication in the influenza virus. Genetic studies suggest that the virus M2 protein, an ion channel specified by virion M2 gene, plays an important role in the susceptibility of influenza A virus to inhibition by rimantadine.Rimantadine is bound inside the pore to amantadine specific amino acid binding sites with hydrogen binding and van der Waals interactions.