Systemic Pharmacology Part II - Midterm II

Tetracyclines are a group of drugs that inhibit bacterial protein synthesis by binding to the 30-S ribosomal subunit. They have bacteriostatic effects and can vary in their effectiveness against Gram-positive bacteria. They are reliable in treating systemic Listeria infections. However, these drugs should be prescribed orally only in rare cases and for specific conditions such as chlamydial inclusion conjunctivitis and trachoma. Tetracycline antibiotics have many potential adverse effects and drug interactions, so they should be prescribed sparingly and with caution. Adverse side effects include photosensitivity and various gastrointestinal effects. Pregnant women and young children should avoid using tetracyclines.

Remember that Drugs w/ "lol" endings fall in the class of beta-adrenergic blocking agents

Cephalosporins have a similar mechanism of action as penicillins and can cause similar gastrointestinal effects and blood dyscrasias. Some cephalosporins may require dose adjustment in patients with renal impairment, just like penicillins. Additionally, it is estimated that 2-10% of patients who are allergic to penicillin will also be allergic to cephalosporins. Allergies to cephalosporins can occur in up to 5% of patients and can range from a rash to a severe allergic reaction known as anaphylaxis. Therefore, the statement "True" is correct.

Azithromycin is not an example of an antiviral agent because it is an antibiotic, specifically a macrolide antibiotic, commonly used to treat bacterial infections. Antiviral agents, on the other hand, are medications that specifically target and inhibit the replication of viruses. Examples of antiviral agents include Acyclovir, Trifluridine, and Vidarabine, which are commonly used to treat viral infections such as herpes simplex related keratitis, keratoconjunctivitis, and herpes zoster.

Frequent or routine use of aspirin or NSAIDs can reduce the effectiveness of antihypertensive medication in people with high blood pressure. This is because aspirin and NSAIDs can interfere with the mechanisms by which antihypertensive medications work, leading to a decrease in their ability to lower blood pressure. Therefore, it is important for individuals with high blood pressure to avoid regular use of these medications without consulting their healthcare provider.

Fluoroquinolones are a category of anti-infective medications that inhibit bacterial DNA-gyrase. They are often bacteriocidal, meaning they kill bacteria, but they are not effective against MRSA and are generally not recommended for Enterococci infections. All drugs in this group have a category "C" rating, indicating that their safety during pregnancy has not been established. One potential adverse effect is the formation of a white precipitate of the active drug at the site of an epithelial defect, which can be mistaken for a worsening infection. Fluoroquinolones can also increase photosensitivity, causing sensitivity to light, and may have various ophthalmic adverse effects. Caution should be exercised when prescribing them to patients taking blood-thinning medications.

Acyclovir works by inhibiting DNA replication and is used for the treatment of ophthalmic Herpes zoster. However, the statement that oral acyclovir can be taken by patients who are sensitive to valacyclovir as this does not cause any cross-sensitivity is false. Both acyclovir and valacyclovir are antiviral medications in the same class called nucleoside analogues, and cross-sensitivity between the two drugs has been reported. Therefore, patients who are sensitive to valacyclovir may also be sensitive to acyclovir.

Macrolides are a class of anti-infective medications that work by inhibiting protein synthesis by binding to the 50-S ribosomal subunit. They are effective against Mycoplasma, Chlamydia, Rickettsia, and some Clostridia. Unlike some other drugs in this class, such as Azithromycin, macrolides do not need to be dose-adjusted in patients with renal impairment. However, they can have potentially serious side effects, including hepatic complications like hepatitis and jaundice, as well as ototoxicity. There is also a possibility of cross-reactivity between different agents in this class, which can range from mild rash to anaphylaxis.

The nagging cough is due to the bradykinin accumulation from the ACE inhibitor

pg. 88 of the manual

Cephalexin is not a penicillin. Penicillins are a class of antibiotics that inhibit bacterial cell wall synthesis and are bacteriocidal. They are commonly used to treat various bacterial infections. Amoxicillin with Clavulanate, Amoxicillin, and Diclocxacillin are all penicillins. Cephalexin, on the other hand, is a cephalosporin antibiotic. While cephalosporins have a similar mechanism of action to penicillins, they are structurally different and not considered penicillins. Therefore, Cephalexin is not a penicillin.

The correct answer is sulfonamides. Sulfonamides inhibit the formation of folic acid in bacteria, which prevents them from synthesizing amino acids and DNA. This mechanism of action makes them effective against bacterial infections such as conjunctivitis and chlamydial infections. However, they are not effective against MRSA. It is important to inform patients that allergic reactions are possible, and these can range from swelling to hives and rash.

pg. 77 of manual

Option 1 - for clindamycin
Option 2 - dosage for moxifloxacin
Option 3 - for acyclovir

Ampicillin is the correct answer because it is an antibiotic that is primarily eliminated through the kidneys. Renal dose adjustments are necessary in patients with impaired renal function to ensure that the medication is properly cleared from the body and to prevent potential toxicity. The other options, Azithromycin, Moxifloxacin, and Doxycycline, do not require renal dose adjustments as they are primarily eliminated through non-renal routes.

Possible dosage for Moxifloxacin: 400mg PO q24hr

Clindamycin - 150mg-450mg PO q6hr
Doxycycline - 100mg PO q12hr
Ampicillin - 250-500mg PO q6hr
Acyclovir - 800mg PO 5x per day

Staphylococcus aureus is a bacterium that can cause various infections, including bacterial keratitis, dacryocystitis, blepharitis, hordeolum, and bacterial conjunctivitis. However, it does not cause protozoan keratitis, which is an infection caused by protozoa.

The statement that there has been no reports of bacterial resistances in Pseudomonas, and that all patients respond quickly to treatment with this class of drugs making culturing unnecessary is false. Bacterial resistance to aminoglycosides, including Pseudomonas, has been reported. Culturing is necessary to determine the susceptibility of the bacteria to the drug and to guide appropriate treatment.

Warfarin is administered orally, it has a high degree of serum protein binding, long T1/2. ADEs include bleeding, necrosis and GI upset.

Doxycycline is a Tetraycline: MOA via inhibition of bacterial protein synthesis by binding to the 30-S ribosomal subunit, cross-sensitivity exists b/t agents in the same class, avoid use during pregnancy. Remember these stain teeth!!!

All of the options except for option II are bacteria. Option II is a fungus

Spironolactone is not known to cause any ocular side effects. Ocular side effects are adverse effects that affect the eyes. While medications like Metoprolol, Doxazosin, and Losartan may cause ocular side effects such as blurred vision, dry eyes, or eye pain, Spironolactone does not have any reported ocular side effects.

pg. 74

Bacitracin works by binding to bacterial cell membranes and interfering with cell wall synthesis, most effects are against sensitive gram positive bacteria

Option 1, 2 and 4 are all inducers

Azithromycin is out immediately b/c it's not an anti-viral.
Acyclovir is out b/c it is used for the treatment of opthalmic herpes zoster - it can cuse encephalopathy, neurotoxicity, blood dyscrasias, coagulation problems, hepatic complications, severe skin reactions, visual changes, GI disturbances, agitation, dizziness, myalgia, paresthesias and other side effects.

Trifluridine is also for herpes simplex related keratitis and keratoconjunctivitis it can cause hyperemia, epithelial keratopathy, increased IOP, dry eye and irritation. Patients should also be warned that is can cause burning or stinging on instillation