Pharmacology Mnemonics - Flash Cards

Name: Ipratropium (Atrovent)

Class: Quaternary M₂-Muscarinic Antagonist

Mech.: Bind to muscarinic receptors and competitively inhib. ACh interaction.

Absorption: Inhalation ® local effect (minimal systemic absorption)

Dist.:

Metab.:

Excretion, t½:

Toxicity/S.E.s:

Utility: Produces bronchodilation. Treat bronchospasm assoc. w/asthma and COPD (including chronic bronchitis and emphysema).

Special Features: Effect prolonged when combined w/a b₂-adrenergic agonist.

Name: Tropicamide (Mydriacil)

Class: Tertiary M₂-Muscarinic Antagonist

Mech.: Bind to muscarinic receptors and competitively inhib. ACh interaction.

Absorption: Eye drops

Dist.:

Metab.:

Excretion, t½:

Toxicity/S.E.s: Topical eye applic. can precipitate glaucoma.

Utility: Apply to conjunctival sac to produce mydriasis and cycloplegia (lasts ~6hr).

Special Features:

Name: Scopolamine (Transderm-Scop)

Class: Tertiary M₂-Muscarinic Antagonist

Mech.: Bind to muscarinic receptors and competitively inhib. ACh interaction.

Absorption: Oral, transdermal, parenteral.

Dist.:

Metab.:

Excretion, t½:

Toxicity/S.E.s: Drowsiness, blurred vision, dry mouth, urinary retention, tachycardia, constipation, cyclopegia. Mostly avoided w/transdermal application.

Utility: Prevent motion sickness (transdermal patch). Give parenterally in advance to counteract nasty anesthesia side effects (cardiac slowing, salivation, bronchial secretions).

Features: In addition to atropine-like anti-musc properties, also produces central depressant and anti-motion sickness effects. Best if admin. prophylactically.

Name: Atropine

Class: Tertiary M₂-Muscarinic Antagonist

Mech.: Bind to muscarinic receptors and competitively inhib. ACh interaction.

Absorption: Syst. absorption from eye drops. Oral good.—use gastric lavage to limit systemic absorption. IV.

Dist.: Selective doses (0.2-0.5 mg) act at muscar. receptors, not at nicot. receptors

Metab.:

Excretion, t½:

Toxicity/S.E.s: Dry as a bone (sweat/saliva blocked), blind as a bat (pupil dilation, no ciliary muscle contraction), red as a beet (flushing and rash over face, neck, upper part of trunk), hot as a hare (no sweat ® ­ temp), mad as a hatter (delirium, toxic psychosis). Urinary retention, constipation. Treat intoxication w/physostigmine. Diazepam relieves CNS effects. Topical eye applic. can precipitate glaucoma.

Utility: Give parenterally in advance to counteract nasty anesthesia side effects (cardiac slowing, salivation, bronchial secretions). Treat anticholinesterase poisoning. Treat urinary problems. Can be applied to eye to produce mydriasis and cyclopegia (lasts 7-12 days).

Name: Pralidoxime (Protopam)

Class: Cholinesterase Reactivator

Mech.: Hydrolyzes phosphorylated AChE, provided the complex has not “aged.”

Absorption:

Dist.: No CNS.

Metab.:

Excretion, t½:

Toxicity/S.E.s:

Utility: Counteracts NM activation and paralysis due to organophosphorous poisoning. Must be given ASAP.

Special Features:

Name: Carbachol

Class: Cholinomimetic Agent

Mech.: Stim. muscarinic and nicotinic receptors. Stim. release of ACh from nerve terminals.

Absorption: Eye drops

Dist.:

Metab.:

Excretion, t½:

Toxicity/S.E.s:

Utility: Topical eye applic. to treat glaucoma. For closed-angle glaucoma, stim. constriction of iris sphincter ® iris removed from entrance to trabecular space. For open-angle glaucoma, stim. sphincter and ciliary body contraction ® ­ patency of trabecular network. Topical for cataract surgery.

Special Features: Use only when pilocarpine doesn’t work, due to unpleasant side effect of ACh release.

Name: Pilocarpine

Class: Cholinomimetic Agent

Mech.: Stim muscarinic receptors.

Absorption: Eye drops

Dist.:

Metab.:

Excretion, t½:

Toxicity/S.E.s:

Utility: Topical eye applic. to treat glaucoma. For closed-angle glaucoma, stim. constriction of iris sphincter ® iris removed from entrance to trabecular space. For open-angle glaucoma, stim. sphincter and ciliary body contraction ® ­ patency of trabecular network.

Special Features:

Name: Bethanechol (Urecholine)

Class: Cholinomimetic Agent

Mech.: Stim. muscarinic receptors. Completely resistant to hydrolysis by AChE or BuChE.

Absorption:

Dist.:

Metab.:

Excretion, t½: Longer duration than methacholine.

Toxicity/S.E.s: Avoid in cases of asthma, coronary insufficiency, peptic ulcers.

Utility: Stim. muscarinic receptors of GI tract and urinary bladder. Treat post-op paralytic ileus and urinary bladder atony.

Special Features:

Name: Acetylcholine

Class: Cholinomimetic Agent

Mech.: Stim. muscarinic and nicotinic receptors.

Absorption:

Dist.:

Metab.:

Excretion, t½: Short duration due to rapid metab. by AChE and BuChE.

Toxicity/S.E.s:

Utility: Topical for cataract surgery.

Special Features: Usu. of limited value due to short duration of action.

Name: Tacrine (Cognex)

Class: Anticholinesterase Agent: Acridinamine

Mech.: Blocks AChE and BuChE. Inhib. M1 and M2 receptors. Weak nicotinic blocker. ­ release of ACh from nerve endings.

Absorption:

Dist.: Good CNS.

Metab.:

Excretion, t½:

Toxicity/S.E.s: Reversible liver damage. Avoid in cases of asthma, coronary insufficiency, peptic ulcers.

Utility: Alzheimer’s disease

Special Features:

Name: Echothiophate (Phospholine)

Class: Anticholinesterase Agent: Organophosphate

Mech.: Binds irreversibly to AChE

Absorption: Eye drops.

Dist.:

Metab.:

Excretion, t½: Long-lasting inhibition—days to weeks.

Toxicity/S.E.s: Toxic doses first stim. then depress autonomic ganglia, neuromusc. jxns, and central sites. Treat w/heroic doses of atropine for muscarinic effects, pralidoxine for neuromusc effects.

Utility: Topical eye applic. to treat glaucoma. For closed-angle glaucoma, stim. constriction of iris sphincter ® iris removed from entrance to trabecular space. For open-angle glaucoma, stim. sphincter and ciliary body contraction ® ­ patency of trabecular network. Topical to treat crossed eyes.

Special Features: Bond btwn drug and AChE must age before becoming irreversible. While bond is aging, drugs such as pralidoxime can reactivate AChE.

Name: Isoflurophate (Floropryl, DFP)

Class: Anticholinesterase Agent: Organophosphate

Mech.: Binds irreversibly to AChE

Absorption:

Dist.: Acts mostly at autonomic sites. Some neuromusc. action.

Metab.:

Excretion, t½: Long-lasting inhibition—days to weeks.

Toxicity/S.E.s: Toxic doses first stim. then depress autonomic ganglia, neuromusc. jxns, and central sites. Treat w/heroic doses of atropine for muscarinic effects, pralidoxime for neuromusc effects.

Utility:

Special Features: Bond btwn drug and AChE must age before becoming irreversible. While bond is aging, drugs such as pralidoxime can reactivate AChE.

Name: Pyridostigmine (Mestinon)

Class: Anticholinesterase Agent: Carbamate (Quaternary Amine)

Mech.: Substrate for AChE. Competitive inhib. of interaction btwn ACh and AChE. Stim. postjxnl nicotinic (i.e., muscular) receptors.

Absorption: Oral adequate.

Metab.: Slowly hydrolyzed by AChE

Dist.: No CNS. Acts mostly at neuromusc sites. Some autonomic action.

Excretion, t½: Slowly hydrolyzed by AChE

Toxicity/S.E.s: Toxic doses first stim. then depress autonom. ganglia, NM jxns, and central sites. Dose too large ® skel. muscle weakness = cholinergic crisis. Too small ® muscle weakness = myasthenic weakness. Avoid in cases of asthma, coronary insufficiency, peptic ulcers.

Utility: Treat myasthenia gravis. Longer acting than neostigmine; used more freq.

Special Features: Non-selective. Stim. cholinergic receptors throughout CNS and PNS. Inhib. AChE and BuChE.

Name: Neostigmine (Prostigmine)

Class: Anticholinesterase Agent: Carbamate (Quaternary Amine)

Mech.: Substrate for AChE. Competitive inhib. of interaction btwn ACh and AChE. Stim. postjxnl nicotinic (i.e., muscular) receptors.

Absorption: Oral adequate.

Dist.: No CNS. Acts mostly at neuromusc sites. Some autonomic action.

Metab.: Slowly hydrolyzed by AChE

Excretion, t½: Slowly hydrolyzed by AChE

Toxicity/S.E.s: Toxic doses first stim. then depress autonomic ganglia, neuromusc. jxns, and central sites. Dose too large ® skeletal muscle weakness = cholinergic crisis. Dose too small ® skeletal muscle weakness = myasthenic weakness. Avoid in cases of asthma, coronary insufficiency, peptic ulcers.

Utility: Treat myasthenia gravis. Treat post-op paralytic ileus and urinary bladder atony. Antag. NM blockade of curare-like agents.

Special Features: IV ® Non-selective. Stim. cholinergic receptors throughout CNS and PNS. Inhib. AChE and BuChE. Musc. effects prevented by pretreatment w/atropine.

Name: Physostigmine (Antilirium)

Class: Anticholinesterase Agent: Carbamate (Tertiary Amine)

Mech.: Substrate for AChE. Competitive inhib. of interaction btwn ACh and AChE.

Absorption:

Dist.: Enters CNS. Acts mostly at autonomic sites. Some neuromusc. action.

Metab.: Slowly hydrolyzed by AChE

Excretion, t½: A few hours.

Toxicity/S.E.s: Toxic doses first stim. then depress autonomic ganglia, neuromusc. jxns, and central sites. Avoid in cases of asthma, coronary insufficiency, peptic ulcers.

Utility: DOC to antag. toxic effects of atropine-like (anticholinergic) drugs.

Special Features: Non-selective. Stim. cholinergic receptors throughout CNS and PNS. Inhib. AChE and BuChE.

Name: Edrophonium (Tensilon)

Class: Anticholinesterase Agent: Choline Analog

Mech.: Combines w/AChE. Competitively prevents interaction of ACh w/AChE.

Absorption:

Dist.: No CNS. Acts mostly at neuromusc sites. Some autonomic action.

Metab.:

Excretion, t½: Brief duration of action (several min.) because binding is rapidly reversible.

Toxicity/S.E.s: Toxic doses first stim. then depress autonomic ganglia, neuromusc. jxns, and central sites. IV—­ skeletal muscle strength = myasthenic weakness; ¯ strength = cholinergic crisis. Avoid in cases of asthma, coronary insufficiency, peptic ulcers.

Utility: IV—test for myasthenia gravis. Antag. NM blockade of curare-like agents. Treat paroxysmal supraventricular tachycardia.

Special Features: IV ® Non-selective. Stim. cholinergic receptors throughout CNS and PNS. Inhib. AChE and BuChE.

Name: Iodide

Class: Antifungal? Halide?

Mech.:

Absorption:

Distribution:

Metab.:

Excretion, t½:

Toxicity/S.E.s:

Utility: Used as alternate treatment for superficial cutaneous Sporotrichosis.

Special Features:

Name: Undecylenic Acid (Desenex)

Class: Antifungal (OTC)

Mech.:

Absorption:

Distribution:

Metab.:

Excretion, t½:

Toxicity/S.E.s:

Utility: <50%>

Special Features:

Name: Tolnaftate (Aftate, Tinactin)

Class: Antifungal (OTC)

Mech.:

Absorption:

Distribution:

Metab.:

Excretion, t½:

Toxicity/S.E.s:

Utility: 80% efficacy against dermatophytes

Special Features:

Name: Ciclopirox (Loprox)

Class: Antifungal (OTC)

Mech.:

Absorption: Penetrates dermis, hair follicles, sebaceous glands.

Distribution:

Metab.:

Excretion, t½:

Toxicity/S.E.s:

Utility: 81-94% cure rate for cutaneous candidiasis, tinea corporis, tinea pedis, versicolor. May (one report) be useful in topical treatment of onychomycosis.

Special Features:

Name: Clortrimazole (Lotrimin)

Class: Antifungal (Imidazole) (OTC)

Mech.: Causes leakage of small molecules/ions across plasma membrane. Also blocks purine uptake. Fungistatic at low conc. Fungicidal at high conc.

Absorption: Good oral, but not admin due to GI irritation. Topical.

Distribution: Good CSF

Toxicity/S.E.s: Topical ® occasional burning and irritation.

Utility: Topical against common fungal infections of skin and vagina. Better than nystatin for vaginal candidiasis. Esp. useful in mixed skin infections featuring dermatophytes and Candida. Good topical agent for dermatophytoses. Troches esp. recommended for oropharyngeal candidiasis.

Special Features: Safe during pregnancy. Broad spectrum against fungi. Also active against gram+ bacteria. At high conc, also trichomonocidal.

Name: Miconazole (Monistat, OTC=Micatin)

Class: Antifungal (Imidazole)

Mech.: Causes leakage of small molecules/ions across plasma membrane. Also blocks purine uptake. Fungistatic at low conc. Fungicidal at high conc.

Absorption: Good oral, but not admin due to GI irritation. Topical, IV, IT.

Distribution: Good CSF

Toxicity/S.E.s: Topical ® occasional burning and irritation. IV/IT may cause cardiorespiratory failure, thrombophlebitis.

Utility: Topical against common fungal infections of skin and vagina. Better than nystatin for vaginal candidiasis. Esp. useful in mixed skin infections featuring dermatophytes and Candida. Best topical agent for dermatophytoses (even severe). Efficacy = 90%. IV/IT as alternative for systemic Pseudallescheriasis infection (only non-topical use).

Special Features: Safe during pregnancy. Broad spectrum against fungi. Also active against gram+ bacteria.

Name: Griseofulvin (Grifulvin)

Class: Antifungal

Mech.: Binds to microtubules, disrupts mitotic spindle, blocks mitosis. Fungistatic.

Absorption: Always given orally. Erratically absorbed. Fatty meals ® ­ absorption.

Distribution: Binds in high conc. to keratin in areas of skin, hair, nails most affected by dermatophytes.

Metab.:

Toxicity/S.E.s: Headache, rare CNS effects (memory lapse, impaired judgment, blurred vision. Candida superinfection. High doses carcinogenic, teratogenic. Disulfiram-like effect with alcohol. Reduces efficacy of some oral contraceptives.

Utility: Inhibits most dermatophytes and superfic. yeast infections. Treats most types of tinea, ringworm, athletes foot.

Special Features: Cures at the base of the problem. When the cured base grow completely out, patient is cured. Long eradication time. Poor cure rate.

Name: Fluconazole (Diflucan)

Class: Antifungal (Triazole)

Mech.: Inhib. fungal cyt. P450 and sterol C-14 a-demethylation. Normal sterols depleted, 14-a-methyl sterols build up ® fungistatic.

Absorption: Oral absorption @ IV absorption (rare phenom.)

Distribution: Low plasma protein binding. Vd close to total body water. Good saliva, good CSF (~80%), conc. in urine and skin.

Metab.:

Excretion, t½: 80% appears in urine unchanged. Excreted in milk. 30 hr.

Toxicity/S.E.s: Rare hepatotoxicity. Rare exfoliative skin disorders (can be fatal). GI irritation, rash. Affects rat fetal development. Increases metabolite levels of some terfenadine metabolits (not terf. itself). May slow metab. of long-acting antihistamines and cyclosporines.

Utility: Candidiasis (oropharyngeal, esophageal, UTI, vaginal, systemic), Cryptococcal meningitis in AIDS patients and otherwise healthy patients. Coccidiodal meningitis. Chronic suppresion of Crypt. meningitis in AIDS patients. Single-dose therapy for vaginal yeast infections.

Special Features: Oral absorption @ IV absorption. Only causes minor changes in plasma testosterone and corticosteroid concentrations.

Name: Itraconazole (Sporanox)

Class: Antifungal (Triazole)

Mech.: Inhib. cytochrome P450-dependent synth of ergosterol.

Absorption: Oral absorption good. Better in presence of food, high gastric acidity.

Distribution: Neglibible CSF, saliva.

Metab.: Extensively metab. in liver.

Excretion, t½: Very little active drug remains in urine.

Toxicity/S.E.s: Nausea, vomiting, headache, rash, loss of libido, impotence, gynecomastia. Rare hepatotoxicity. Inhib. metab. of long-acting antihistamines (sim. to ketoconazole), erythromycin, triazolam, cisapride.

Utility: DOC for many superficial and systemic infections. Alternate for many superf. and systemic infections. Oral treatment of onychomycoses. Same indications as ketocon., but also active against lymphocutaneous form of sporotrichosis plus Aspergillosis. Usu. preferred to ketoconazole.

Special Features:

Name: Ketoconazole (Nizoral)

Class: Antifungal (Imidazole)

Mech.: Interferes w/ergosterol synth ® altered fungal membrane permeability.

Absorption: Absorbed well from GI if contents are sufficiently acidic.

Distribution: Poor CSF at recommended doses. Ok CSF w/high doses.

Metab.: Degraded by liver.

Excretion, t½: Excreted mostly into bile. Only 10-15% appears unchanged in urine. Excreted in milk.

Toxicity/S.E.s: Fewer than Amphoter. or flucytosine. Rare fatal hepatic necrosis. Dose-dependent decrease in testosterone. Toxicities for nursing infants. Rare anaphylactic shock. Can’t be used w/astemizole, terfenadine, loratadine due to inhib. of metabolism. Coadmin. w/ketoconazole ® ­ conc. of cyclosporin. Increases anticoag. response of anticoag drugs. Coadmin w/isoniazid or rifampin ® ¯ ketoconazole.

Utility: DOC for Pseudoallescheria boydii. Alternate for C. albicans, H. capsulatum, B. dermatidis, Paracoccidiodes, C. immitis.

Special Features: Very broad spectrum. Being phased out and replaced with itraconazole and fluconazole.

Name: Flucytosine (Ancobon)

Class: Antifungal

Mech.: Converted to 5-fluorouracil in fungi (enzyme not in humans). 5-fluorouracil ® phosph deoxyribose that inhibits thymidylate synth. Fungistatic.

Absorption: Well absorbed orally.

Distribution: Passes BBB (75%) ® good CSF. Aqueous humor, bronchial secretions. Poorly bound by serum proteins.

Metab.:

Excretion, t½: 1° glomerular filtration (unmetab. product). 3-4 hr ® 200 hr w/renal failure. Dose must be adjusted if renal fxn compromised.

Toxicity/S.E.s: Bone marrow depression with anemia, thrombocytopenia, leukopenia. Nausea, rashes, eosinophilisa, severe diarrhea, reversible hepatic dysfxn. Confusion, hallucinations, headache, vertigo, possibly fatal enterocolitis (esp. in comb. w/Amphoter.).

Utility: DOC for Chromomycosis. Used in comb. w/Amph for systemic Candida Albicans.

Special Features: Narrower spectrum than Amphotericin B. Resistance develops rapidly, so usu. used in comb., except to treat Chromomycosis

Name: Nystatin

Class: Antifungal (Polyene)

Mech.: Assoc. w/ergosterol in fungal membrane ® 4-5 Å pores. Fungistatic at low conc. Fungicidal at high conc.

Absorption: Poor oral absorption. Topical admin.

Distribution:

Metab.:

Excretion, t½:

Toxicity/S.E.s: No side effects when topically applied

Utility: Superficial candidiasis (GI, cutaneous, oropharyngeal, vulvovaginal) via topical, oral, or vaginal admin.

Special Features: Safe during pregnancy.

Name: Amphotericin B (Fungizone)

Class: Antifungal (Polyene)

Mech.: Assoc. w/ergosterol in fungal membrane ® 4-5 Å pores. Fungistatic at low conc. Fungicidal at high conc.

Absorption: Insoluble in water. Colloidal preparation injected IV. Not absorbed orally, IM, or after bladder irrigation. Used topically.

Distribution: Bound to cholesterol and lipoprotiens. Poor CSF. Intrathecal may be necessary to treat meningitis.

Excretion, t½: Excreted very slowly as inactive metabolite by kidney.

Toxicity/S.E.s: Nephrotoxicity (80%) requires hospitalization for administration. Chills (50%), fever, nausea, vomiting, diarrhea, headache, phlebitis, suppression of RBC synth. IT ® headache, radiculitis, paresis, paresthesias, visual impairment.

Utility: 1° drug used against serious systemic infections. DOC for 1° amebic meningoencephalitis caused by Naegleria. Alt. for American cutaneous or mucocutaneous leishmoniasis. Weekly injections for chronic suppression of Histoplasmosis in AIDS patients.

Special Features: No problem w/resistance development. Increases fungal permeability to other agents.

Name: Pyrazinamide

Class: Antitubercular

Mech.: Bactericidal. Unknown mech.

Absorption: Well absorbed orally. Not affected by food.

Distribution: Dist. in total body water.

Metab.: Partially metabolized — hydrolyzed, hydroxylated

Excretion, t½: Glomerular filtration. 8 hrs.

Toxicity/S.E.s: Liver necrosis, hyperuricemia, nausea, vomiting, complication of diabetes management.

Utility: Used to treat TB when there is resistance to other agents. Requires 3 additional effective agents.

Special Features:

Name: Ethambutol (Myambutol)

Class: Antitubercular

Mech.: Tuberculostatic, mech. unknown, may involve inhib of mycolic acid synth.

Absorption: Well absorbed orally. Not affected by food.

Distribution:

Metab.:

Excretion, t½: Renal excretion (50% unchanged and 15% inactive metab. in 24 hr)

Toxicity/S.E.s: Few. Decreased visual acuity and ability to perceive color green (usually reversible). Gout.

Utility: Treat TB. Resistance develops is used alone. Usu. used with isoniazid.

Special Features:

Name: Rifampin (Rifadin)

Class: Antitubercular

Mech.: Inhib. of bact. DNA-dependent RNA polymerase. Resist develops rapidly.

Absorption: Orally effective

Distribution: Diffuses freely into tissues and fluids

Metab.: Liver

Excretion, t½: 30% excreted in urine (50% active). T1/2= 1.5-5 hrs. ¯ in slow acetylaters.

Toxicity/S.E.s: Low incidence. Jaundice (can be fatal). Use w/caution w/impaired liver fxn. Induces hepatic microsomal enzymes. GI distress, diarrhea, CNS complaints, hypersensitivity. Influenza-like syndrome.

Utility: Rapidly improves TB patients to non-infectious state. Always used w/other agents. Esp. useful in serious cases of TB. Asymptomatic carriers of N. meningitis, eryth-resist. Legionella pneumophila infects. DOC for prophylaxis of H. influenza meningitis.

Name: Isoniazid (INH)

Class: Antitubercular

Mech.: Tuberculostatic to resting bacilli, tuberculocidal to rapidly dividing cells. Enters cells via active uptake. Interferes w/DNA synth, glycolyis, synth of mycolic acid (unique component of mycobacteria)

Absorption: Rapidly absorbed after oral admin.

Distribution: Distributes in total body water. Retained in infected tissue.

Metab.: Acetylated in liver.

Excretion, t½: Urine. 75-90% in urine as metabolites in 24 hrs.

Toxicity/S.E.s: Direct—inactivation/depletion of pyridoxine ® peripheral neuritis (treat prophylactically w/supplemental pyridoxine). Hypersensitivity rxns. Hepatitis (can be fatal) due to toxic metabolites. Convulsions, optic neuritis, toxic encephalopathy, reversible psychotic episodes.

Utility: Most important and widely used drug for tuberculosis. Prob. w/resistance.

Special Features: Only drug approved for prophylaxis of tuberculosis.

Name: Saquinavir (Invirase)

Class: Antiviral

Mech.: Inhib HIV protease activity

Absorption: Oral

Distribution:

Metab.:

Excretion, t½:

Toxicity/S.E.s:

Utility: Treat HIV

Special Features: Active against strains resistant to reverse transcriptase inhibitors.

Name: Ritonavir (Norvir)

Class: Antiviral

Mech.: Inhib HIV protease activity

Absorption: Oral

Distribution:

Metab.:

Excretion, t½:

Toxicity/S.E.s:

Utility: Treat HIV

Name: Indinavir (Crixivan)

Class: Antiviral

Mech.: Inhib HIV protease activity

Absorption: Oral

Distribution:

Metab.:

Excretion, t½:

Toxicity/S.E.s:

Utility: Treat HIV

Special Features: Active against strains resistant to reverse transcriptase inhibitors.

Name: Dideoxycytosine (Zalcitabine, Hivid, DDC))

Class: Antiviral

Mech.: Inhib reverse transcriptase.

Absorption:

Distribution:

Metab.:

Excretion, t½:

Toxicity/S.E.s: Peripheral neuropathy, rash, stomatitis, esophageal ulceration, pancreatitis, fever.

Utility: Treat HIV. Strains resistant to AZT may be susceptible. After treatment, may become susceptible again to AZT. Alternating treatment superior to either alone.

Special Features:

Name: Dideoxyinosine (Didanosine, Videx, DDI)

Class: Antiviral

Mech.: Inhib reverse transcriptase.

Absorption:

Distribution:

Metab.:

Excretion, t½:

Toxicity/S.E.s: Peripheral neuropathy, rash, stomatitis, esophageal ulceration, pancreatitis, fever.

Utility: Treat HIV. Strains resistant to AZT may be susceptible. After treatment, may become susceptible again to AZT. Alternating treatment superior to either alone.

Special Features:

Name: Azidothymidine (Zidovudine, AZT)

Class: Antiviral

Mech: Thymidine analog. After phosph, inhib. viral RNA-dependent DNA polymerase (reverse transcriptase). Causes chain termination after incorporation.

Absorption: Oral bioavail 60-65%.

Distribution: good CSF

Metab.: Metab. to glucuronide. Antag. by ribavirin

Excretion, t½: 1 hr.

Toxicity/S.E.s: Granulocytopenia (45%), anemia (transfusions necessary 30%), headache, nausea, insomnia, myalgia.

Utility: Treatment of HIV. Decreases plasma HIV RNA, increases CD4 cells, decreases # of opportunistic infects, prolongs survival. Reduces risk of transmission by pregnant women to fetuses from 28% to 8%.

Special Features:

Name: Ribavirin (Virazole)

Class: Antiviral

Mech.: Purine analog. After phosphorylation, inhibits enzymes involved in guanine nucleotide synth. After further phosph, inhib several viral-specific enzymes involved in DNA synth.

Absorption: Oral bioavail 45%. IV. Aerosol.

Distribution:

Metab.:

Excretion, t½: 40 days

Toxicity/S.E.s: Accumulates in erythrocytes ® hemolytic anemia. Bone marrow suppression. GI, CNS aggravation. Teratogenic and mutagenic in animals. Toxicity avoided w/aerosol admin (for RSV). Antagonizes AZT activity.

Utility: Aerosol form used to treat respiratory syncytial virus. Most important drug for treatment of hemorrhagic fever.

Special Features:

Name: Rimantadine (Flumadine)

Class: Antiviral

Mech.: Blocks a late stage in assembly of influenza A virus

Absorption: Well absorbed orally.

Distribution:

Metab.: Hepatic metab.

Excretion, t½:

Toxicity/S.E.s: CNS toxicity (nervousness, confusion, hallucinations, insomnia) amantadine>rimantadine

Utility: Treat influenza A

Special Features: Can be used prophylactically.

Name: Amantadine (Symmetrel)

Class: Antiviral/Antiparkinsonian Agent

Mech.: Blocks a late stage in assembly of influenza A virus

Absorption: Well absorbed orally.

Distribution:

Metab.:

Excretion, t½: Excreted unchanged in urine.

Toxicity/S.E.s: CNS toxicity (nervousness, confusion, hallucinations, insomnia, depression, confusion). Overdose ® toxic psychosis. Freq. livedo reticularis (skin mottling). Peripheral edema, freq. nausea. C/I w/hist. of seizures or congestive heart failure. Amantadine>rimantadine

Utility: Treat influenza A. Treat Parkinson’s Disease symptoms ® improvement o akinesia, rigidity, tremor, gait disturbances, & total disability in ~ 50% of patients (mech. unknown). Use alone or w/L-Dopa for PD.

Features: Can be used prophylactically for influenza A. For PD, sustained improvement may last up to 30 months, but may also be short lived (1-3 months). For PD, as good as or better than anticholinergics.

Name: Interferon alpha 2b (Intron A)

Class: Antiviral

Mech.: Bind to cell-surface receptors and inhibit viral penetration or uncoating, synth or methylation of mRNA, translation of viral proteins, viral assembly or release, and degrade mRNA. ® Inhib. viral protein synth. Also induce a protein kinase that inactivates protein eIF-2 which is necessarty for protein synth initiation.

Absorption: Low oral activity. Usu. given IM or SC

Distribution:

Metab.: Rapid degradation.

Excretion, t½: 40 min.

Toxicity/S.E.s: influenza-like illness. Bone marrow suppression w/granulocytopenia and thrombocytopenia. Antibodies develop w/continued use. Continued nasal admin ® mucosal damage.

Utility: Treat hepatitis B and C

Name: Trifluridine (Viroptic)

Class: Antiviral

Mech.: Pyrimidine analog. Competes with TTP for incorp into viral DNA. Inhib. viral DNA synth.

Absorption:

Distribution: 1% soln applied to cornea. Not given systemically

Metab.:

Excretion, t½:

Toxicity/S.E.s: Mutagenic and teratogenic activity in experimental tests.

Utility: Topical treatment for keratoconjunctivitis.

Special Features:

Name: Foscarnet (Foscavir)

Class: Antiviral

Mech.: Phosph by viral thymidine kinase. Competes w/normal nucleotides. Prevents chain elongation upon incorporation. Also inhib. viral and cellular DNA polymerase.

Absorption: Poor oral. Usu. given IV.

Distribution: Good CSF

Metab.:

Excretion, t½: Renal excretion. 4 hr.

Toxicity/S.E.s: Renal dysfxn #1. Nausea, vomiting, headache, fatigue, anemia.

Utility: Cytomegalovirus

Special Features: 3x more expensive than gancyclovir.

Name: Ganciclovir (Cytovene)

Class: Antiviral

Mech.: Phosph by viral thymidine kinase. Competes w/normal nucleotides. Prevents chain elongation upon incorporation. Also inhib. viral and cellular DNA polymerase.

Absorption: Poor oral. Usu. given IV.

Distribution: Good CSF

Metab.:

Excretion, t½: Renal excretion. 4 hr.

Toxicity/S.E.s: Bone marrow suppression. Teratogenic and mutagenic in experimental animals.

Utility: Cytomegalovirus

Special Features:

Name: Acyclovir (Zovirax)

Class: Antiviral

Mech.: Inhib. DNA synthase (most selective for herpes virus). Phosphorylated by viral thymidine kinase. Then inhib. viral DNA polymerase by competing w/deoxyguanosine triphosphate.

Absorption:

Distribution:some CSF

Metab.:

Excretion, t½: Renal secretion, 2.5 hr.

Toxicity/S.E.s: Topical admin may cause loal irritation. IV may cause local phlebitis, rash. Encephalophaty in renal-impaired.

Utility: Topical, oral, IV application to treat herpes infections.

Special Features:

Name: Metronidazole (Flagyl)

Class: Nitroimidazole derivative

Mech.: Inhib. DNA synth, degrades DNA, e- acceptor for reduced substrates.

Absorption: Complete, quick oral absorption.

Distribution: Well distrib to all tissues and fluids (including CSF)

Metab.: Hepatic metab.

Excretion, t½:

Toxicity/S.E.s: GI, metallic taste, neurotox (vertigo), disulfiram-like effect w/alcohol, neutropenia. Not for first trimester preg (mutagenic). Not for patients w/active CNS disease or hist. of blood dyscrasias.

Utility: IV treatment of anaerobic infects. Oral for amebiasis, giardiasis, and genital infects of Trichomonas vaginalis.

Special Features: Antiparasitic and antibacterial activity. All anaerobic cocci and anaerobic gram- bacilli, including Bacteriodes. Trichomonasis, amebiasis, giardiasis.

Name: Vancomycin (Vancocin)

Class: Polypeptide

Mech.: Blocks peptidoglycan polymerization ® inhib cell wall synth. Bactericidal.

Absorption: Poorly absorbed from GI tract. Usu given IV

Distribution: Poor CNS

Metab.:

Excretion, t½: Renal excretion

Toxicity/S.E.s: Ototoxicity, nephrotoxicity, thrombophlebitis (IV). In patients w/AIDS, “red man” syndrome (diffuse flushing)

Utility: Last ditch measure against severe MRSA infects. DOC for antibiotic assoc. pseudomembranous colitis (oral).

Special Features: Narrow spectrum (gram+ cocci), spec. MRSA, C. difficile.

Name: Clindamycin (Cleocin)

Class: Lincosamide

Mech.: Inhib protein synth by binding to 50S rib. subunit. Bacteriostatic.

Absorption: Nearly complete oral absorption. IV.

Distribution: Good into most tissues, including bone. Poor CSF.

Metab.: Hepatic metab.

Excretion, t½: Renal excretion. 2.7 hr.

Toxicity/S.E.s: High incidence of diarrhea. Antibiotic-assoc. pseudomembranous colitis. Skin rashes. Local thrombophlebitis due to IV.

Utility: Alternate to pen. or eryth. in susceptible infections. One DOC for non-CNS anaerobic infections. Used topically for acne.

Special Features:

Name: Azithromycin (Zithromax)

Class: Macrolide (azalide)

Mech.: Inhib protein synth by binding to 50S rib. subunit. Bacteriostatic

Absorption: Good oral. Better than erythromycin.

Distribution: Good tissue penetration. Better than erythromycin.

Metab.: Hepatic metab.

Excretion, t½: Bile excretion. 68 hrs.

Toxicity/S.E.s: fewer than erythromycin, esp. GI. No interference w/cytochrome p450 metab.

Utility: Alternate to pen. in mild-moderate infects (esp. Strep, H. influenzae). DOC for Legionnaire’s disease, Diphtheria carrier state, Mycoplasma pneumoniae infects, Whooping cough (Bordatella pertussis)

Special Features: Expanded spectrum over classic macrolides (more potent against gram- bacilli, chlamydiae).

Name: Erythromycin

Class: Macrolide

Mech.: Inhib protein synth by binding to 50S rib. subunit. Bacteriostatic

Absorption: Orally effective. Enteric-coated tablets.

Distribution: Good tissue penetration, but poor CSF.

Metab.: Hepatic metab.

Excretion, t½: Secreted in bile as active drug. 1.6 hr.

Toxicity/S.E.s: GI irritation.,rashes, ototoxicity (large parenteral doses), drug interactions due to inhib of hepatic metab.

Utility: Alternate to pen. in mild-moderate infects (esp. Strep, H. influenzae). DOC for Legionnaire’s disease, Diphtheria carrier state, Mycoplasma pneumoniae infects, Whooping cough (Bordatella pertussis)

Special Features: Not recommended for severe staph. infections or for meningitis.