Browsing Pathways

Bezitramide is a narcotic analgesic that has been withdrawn due to overdoses. It is taken orally with a long duration of action. Bezitramide binds to opioid receptors, stimulating the exchange of GTP for GDP on the G-protein complex. As the effector system is adenylate cyclase and cAMP located at the inner surface of the plasma membrane, opioids decrease intracellular cAMP by inhibiting adenylate cyclase. Subsequently, the release of nociceptive neurotransmitters such as GABA is inhibited. Opioids close N-type voltage-operated calcium channels and open calcium-dependent inwardly rectifying potassium channels. This results in hyperpolarization and reduced neuronal excitability. Morphine acts at A delta and C pain fibres in the dorsal horn of the spinal cord. By decreasing neurotransmitter action there is less pain transmittance into the spinal cord. This leads to less pain perception.

Bictegravir is an integrase inhibitor used to treat HIV-1 and HIV-2 infections. Bictegravir is indicated in the management of HIV-1 infection in patients not previously treated with antiretroviral therapy. Additionally, Bictegravir is indicated in the management of HIV-1 infection in patients who are virologically suppressed (HIV-1 RNA <50 c/mL) on a regular antiretroviral regimen for a minimum of three months without a history of failure in treatment and no known factors associated with the resistance to the individual components of the medication. In vitro, bictegravir has shown powerful antiviral activity against HIV-2 and various subtypes of HIV-1. It is used in combination with tenofovir and emtricitabine. Bictegravir is transported into the infected cell then transported into the nucleus via importin nuclear transporter. The viral RNA is injected into the cell then transcribed into viral DNA via reverse transcriptase. It is then transported into the nucleus where it is integrated into the host DNA. Bictegravir inhibits HIV integrase which prevents the viral DNA from being integrated into the host DNA. This prevents viral replication and further progression of the virus. It is used in combination with reverse transcriptase inhibitors which further prevents viral replication and progression of the virus.

Bifonazole is an azole anti-fungal drug used to treat fungal skin infections, such as dermatomycosis and athlete's foot. It comes as a cream which is spread on the infected skin. Bifonazole inhibits lanosterol 14-alpha demethylase in the endoplasmic reticulum of fungal cells. Lanosterol 14-alpha demethylase is the enzyme that catalyzes the synthesis of 4,4'-dimethyl cholesta-8,14,24-triene-3-beta-ol from lanosterol. With this enzyme inhibited ergosterol synthesis cannot occur which causes a significant low concentration of ergosterol in the fungal cell. Ergosterol is essential in maintaining membrane integrity in fungi. Without ergosterol, the fungus cell cannot synthesize membranes thereby increasing fluidity and preventing growth of new cells. This leads to cell lysis which causes it to collapse and die.