Pharm Flashcards
Drugs that have been shown to improve long-term survival in patients with heart failure 2/2 left ventricular systolic dysfunction
- Beta blockers (eg, carvedilol, metoprolol)
- ACE inhibitors (eg, lisinopril, ramipril)
- Angiotensin II receptor blockers aka ARBs (eg, valsartan)
- Aldosterone antagonists (eg, spironolactone, eplerenone)
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Amiodarone
- Class III antiarrhythmic agent.
- Prolongs APD and therefore QT interval by blocking outward potassium currents during phase 3 of AP, prolonging repolarization.
- Unlike other drugs that cause QT prolongation, AMIODARONE has very little risk of inducing torsades de pointes. Thought to be 2/2 more homogenous effect on ventricular repolarization than other drugs (ie, less QT dispersion).
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Digoxin
- Prolongs AV nodal conduction by augmenting vagal parasympathetic tone
- Increases cardiac contractility by inhibiting Na+/K+ATPase (increasing intracellular calcium).
- Decreases APD and can cause QT interval shortening rather than prolongation.
- Improves symptoms of HF and reduces rate of hospitalization but has not been shown to improved overall survival.
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Flecainide
- Class IC antiarrhythmic
- Used occasionally for management of SVT in patients with a structurally normal heart.
- Slows AP conduction velocity by blocking sodium channels (phase 0 of AP).
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Theophylline
- Adenosine receptor antagonist, phosphodiesterase inhibitor and indirect adrenergic agent used sometimes as an alternate therapy for COPD/asthma, with a NARROW therapeutic index.
- Causes bronchodilation by increasing intracellular cAMP and has mild anti-inflammatory effects.
- Metabolized by hepatic cytochrome oxidases. Inhibition of these enzymes by concurrent illness or drugs can raise serum concentration and cause theophylline toxicity 2/2 drug’s narrow TI (eg, Ciprofloxacin-induced theophylline toxicity).
- Theophylline toxicity presents as excessive CNS stimulation (eg, tremor, insomnia, seizures), GI disturbances, and CV abnormalities (eg, cardiac arrhythmias, hypotension, tachycardia).
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Drugs that inhibit hepatic cytochrome oxidases
Cimetidine, ciprofloxacin, macrolides, verapamil
Biologic response modifiers (BRMs)
Class of treatments including antibiotics, cytokines, and other substances that are intended to restore or induce the immune system’s ability to overcome disease.
Rituximab
A monoclonal antibody used in lymphoma immunotherapy that targets the CD20 surface immunoglobulin expressed on B-cells.
Trastuzumab
Trastuzumab (Herceptin) is a monoclonal antibody used to treat breast cancer that targets HER2-neu receptor expressed by some breast cancers.
Infliximab
A chimeric (human/murine) IgG1 monoclonal antibody against TNF-alpha. Used to treat RA, ankylosing spondylitis and fistulizing Crohn’s disease.
Interleukin-2
Cytokine that regulates activation and differentiation of T-cells to aid in tumor cell destruction. FDA-approved for treatment of renal cell carcinoma and melanoma.
Imatinib mesylate
A small molecule potent inhibitor of the BCR/ABL fusion protein tyrosine kinase expressed in CML (due to the Philadelphia chromosome mutation). Imatinib inhibits the proliferation of BCR/ABL-expressing cells without inducing apoptosis. Imatinib has dramatically changed management of CML.
Abciximab
A chimeric mouse-human monoclonal antibody against the platelet GP IIB/IIIa receptor. It works by blocking the final step in platelet aggregation and is often administered during angioplasty in patients with ACS.
Sacubitril
A neprilysin inhibitor, prevents the degradation of ANP by neprilysin, enhancing its beneficial hemodynamic effects in HF patients, ie, natriuresis, vasodilation, and diuresis.
Side effects of loop diuretics (eg, furosemide, torsemide, bumetanide)
- Inhibit Na/K/2Cl symporters in ascending limb of loop of Henle.
- Inhibition of similar symporters in inner ear believed to cause ototoxicity (tinnitus, vertigo, hearing impairment, deafness) seen with loop diuretic use.
- Ototoxicity typically occurs with higher doses, preexisting CKD, rapid IV administration or when used in combination with other ototoxic agents (aminoglycosides, salicylates, cisplatin).
- Additional side effects include hypokalemia, hypomagnesemia, and hypocalcemia.
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Ototoxic drugs
- Loop diuretics (furosemide, torsemide, bumetanide)
- Aminoglycosides (gentamicin, tobramycin, amikacin)
- Salicylates (aspirin)
- Cisplatin
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Digoxin toxicity
Cardiac arrhythmias, hyperkalemia, N/V, confusion
HCTZ side effects
Hypokalemia, hyponatremia, hypomagnesemia, hypercalcemia
ACE inhibitor side effects
Cough (bradykinin), hyperkalemia, angioedema, anaphylactoid reactions
Spironolactone
- Aldosterone antagonist (competitive inhibitor) with mild K-sparing diuretic effects.
- Blocks detrimental cardiac effects of aldosterone (ie, produced by myocardium in HF, leading to fibrosis and myocardial hypertrophy, resulting in cardiac remodeling that worsens LV dysfunction.)
- Structurally similar to androgens and acts as androgen receptor antagonist, inhibiting testosterone synthesis.
- Adverse effects: hyperkalemia, b/l or unilateral gynecomastia, impotence, decreased libido.
- Eplerenone is a newer, more selective aldosterone antagonist that produces fewer endocrine side effects.
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Acetazolamide
- Inhibits carbonic anhydrase, enzyme found in high concentrations in proximal renal tubule responsible for catalyzing reactions necessary for HCO3- reabsorption.
- Inhibition of CA blocks HCO3- reabsorption, resulting in HCO3- and H2O excretion, causing alkaline urine and metabolic acidosis.
- CA also present in eyes, pancreas, GI tract, CNS, and RBCs.
- In the eye, inhibition of CA decreases HCO3- secretion and aqueous humor formation, thus relieving intraocular pressure in glaucoma.
- Adverse effects: somnolence, paresthesias, urine alkalinization.
- Rare side effects include metabolic acidosis, dehydration, hypokalemia, and hyponatremia.
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How do OCPs work to reduce hirsutism in PCOS?
- Decrease ovarian androgen production by suppressing LH secretion from pituitary through negative feedback.
- Also increase sex hormone binding globulin (SHBG) synthesis by liver, decreasing free testosterone levels.
- Androgen receptor antagonists (eg, spironolactone) also effective in suppressing androgen-dependent hair growth.
- 5-alpha reductase inhibitors (eg, finasteride) decrease peripheral conversion of testosterone to DHT but less effective than spironolactone in treating hirsutism.
- Both spironolactone and finasteride strongly teratogenic.
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Eflornithine
Topical ornithine decarboxylase inhibitor used to decrease rate of facial hair growth. Inhibition leads to decreased cell growth and increased apoptosis.
Clomiphene
Selective estrogen receptor modulator that prevents negative feedback inhibition on the hypothalamus and pituitary by circulating estrogen, resulting in increased gonadotropin production (FSH and LH) and ovulation.
Metyrapone
11-beta-hydroxylase inhibitor. Blocks cortisol synthesis.
Bromocriptine
Dopamine agonist. Decreases pituitary release of prolactin, useful in patients with infertility due to hyperprolactinemia or in patients with pituitary prolactinoma.
Cabergoline
Dopamine agonist. Decreases pituitary release of prolactin, useful in patients with infertility due to hyperprolactinemia or in patients with pituitary prolactinoma.
Dantrolene
Relaxes skeletal muscle by reducing the release of Ca++ from the sarcoplasmic reticulum. Used to tx malignant hyperthermia and neuroleptic malignant syndrome.
Nondepolarizing NMJ muscle relaxants
- Vecuronium, rocuronium, pancuronium, tubocurarine.
- Competitively inhibit postsynaptic ACh receptors at motor endplate as well as presynaptic ACh receptors, leading to progressively less ACh release at the NMJ.
- Competitive inhibition of postsynaptic receptors prevents activation of some muscle fibers, decreasing strength of twitch compared to normal muscle twitch.
- TOF stimulation displays progressive reduction in each of 4 responses (fading pattern) as result of less Ach being released with each subsequent impulse 2/2 the additional effect of presynaptic Ach receptor blockade.
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Neostigmine
- Reversible acetylcholinesterase inhibitor.
- Tx myasthenia gravis
- Used routinely in anesthesia to reverse nondepolarizing muscle relaxants (rocuronium, vecuronium) at the end of an operation.
- Tx postoperative or neurogenic ileus and urinary retention.
- As quaternary amine, does not penetrate CNS like physostigmine does. NEOstigmine = NO CNS.
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Train-of-four (TOF) stimulation
- Used during anesthesia to assess degree of paralysis induced by NMJ-blocking agents.
- Peripheral nerve stimulated 4 times in quick succession and muscular response recorded.
- Height of each bar represents the strength of each twitch, with higher bars indicating the activation of increasing numbers of individual myocytes.
- Nondepolarizing blockade always shows a fading pattern, depolarizing blockade always has a constant but diminished phase I and later a phase II fading pattern.
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Depolarizing NMJ muscle relaxants
- Succinylcholine.
- Initially functions by preventing repolarization of motor endplate, causing equal reduction of all 4 twitches during TOF stimulation (phase I blockade).
- Responses remain equal b/c presynaptic ACh receptor stimulation mobilizes presynaptic Ach vesicles for release.
- Persistent exposure to succinylcholine results in eventual transition to phase II blockade as ACh receptors become desensitized and inactivated.
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Class III antiarrhythmic drugs
Potassium channel blockers. Inhibit outward potassium currents during phase 3 of cardiac AP, prolonging repolarization and total action potential duration (APD), with no effect on AP conduction velocity. Prolong QT interval. Eg, amiodarone, dronedarone, dofetilide, sotalol (also class II).
QT prolongation
- QT interval represents time required for ventricular depolarization and repolarization; can be thought of as a rough estimate of the APD.
- Drugs that prolong cardiac APD (eg, class IA and III antiarrhythmics) will cause QT prolongation.
- Prolonged QT is associated with torsades de pointes (polymorphic VT).
- However, unlike other drugs that cause QT prolongation, AMIODARONE has very little risk of inducing torsades de pointes. 2/2 more homogenous effect on ventricular repolarization than other drugs (ie, less QT dispersion).
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Class IA antiarrhythmic drugs
- Sodium channel blockers.
- Inhibit sodium-dependent depolarization (phase 0) causing slowed AP conduction velocity.
- Moderate potassium channel blocking activity (phase 3) leading to prolongation of APD, and therefore the QT interval.
- Increased risk of torsades de pointes.
- Eg, Disopyramide, procainamide, quinidine.
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Class IB antiarrhythmic drugs
- Sodium channel blockers.
- Inhibit sodium-dependent depolarization (phase 0).
- Shortens APD (and therefore does not prolong the QT interval). No effect on AP conduction velocity.
- Eg, Lidocaine, phenytoin, mexiletine.
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Class IC antiarrhythmic drugs
- Sodium channel blockers.
- Inhibit sodium-dependent depolarization (phase 0) causing slowed AP conduction velocity. Minimal effect on APD and QT interval.
- Eg, Flecainide, propafenone.
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Class II antiarrhythmic drugs
- Beta receptor blockers.
- Slow sinus node discharge rate. Slow AV nodal conduction and prolong refractoriness.
- Eg, Atenolol, metoprolol, esmolol, carvedilol.
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Class IV antiarrhythmic drugs
- Non-dihydropyridine calcium channel blockers.
- Slow sinus node discharge rate. Slow AV nodal conduction and prolong refractoriness.
- Eg, Verapamil, diltiazem.
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Adenosine
- Interacts with A1 receptors on cardiac cells and activates K+ channels, increasing K+ conductance.
- Causes transient conduction delay through AV node
- Used for acute termination of paroxysmal supraventricular tachycardia (PSVT).
- Rapidly metabolized in blood and tissues, with very brief duration of action (must be flushed with saline when administered to ensure reaching the AV node before degradation).
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Esmolol
Rapidly-acting, short-duration beta-blocker (class II antiarrhythmic) that slows the rate of discharge of sinus node or ectopic pacemakers and increases refractory period of AV node. No effect on QT interval prolongation.
Succinylcholine
- Fast-acting (less than 1 min), depolarizing neuromuscular blocking agent (muscle relaxant) used for rapid-sequence intubation that causes equal reduction of all 4 twitches during TOF stimulation (phase I blockade).
- Cholinesterase metabolism determines duration of action, typically less than 10 mins.
- Prolonged administration or use in patients with atypical cholinesterase activity (homozygous mutation that causes slowed metabolism of succinylcholine) causes transition to phase II blockade with progressive reduction in each of 4 twitches.
- Paralysis can last for hours in these patients and they must be maintained on mechanical ventilation until spontaneous respiration resumes.
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Selegiline
- MAO, type B inhibitor.
- Prevents MPTP-induced damage of dopaminergic neurons in substantia nigra (MPTP is a toxin that is converted to MPP+ by MAO-B. )
- MPP+ metabolite causes a Parkinsonism-like syndrome by destroying CNS dopaminergic neurons, and can be inhibited by Selegiline if given beforehand.
- Used clinically to delay progression of Parkinson disease (PD).
- Many neurologists favor use of combinations of selegiline, anticholinergics, and amantadine until they no longer provide control of symptoms, then starting levodopa/carbidopa.
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Levodopa/carbidopa
- Dopamine absent in the nigrostriatum of patients with Parkinson disease.
- Levodopa is immediate precursor of DA and can cross blood brain barrier.
- Levodopa absorbed in small intestine and converted to DA by DOPA-decarboxylase.
- Peripheral conversion of L-dopa responsible for N/V
- Carbidopa is a DOPA-decarboxylase inhibitor that doesn’t cross BBB, therefore decreasing peripheral formation of DA, causing less side effects and allowing more levodopa to reach brain.
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Pergolide
Dopamine agonist at D2 receptors. Shows only modest improvement in Parkinson symptoms as monotherapy but may delay introduction of levodopa by months to years.
Amantadine
May provide moderate improvement in patients with Parkinson disease. Initially designed as an antiviral influenza agent and found to have dopaminergic activity and possible anticholinergic action as well. Mechanism of action not well known. Side effects: dry mouth, N/V, visual blurring, mental changes, use with caution in the elderly.
Dofetilide
Class III antiarrhythmic used to maintain sinus rhythm is patients with atrial fibrillation or other SVTs. Risks include serious ventricular arrhythmias (2/2 QT prolongation) and conduction disturbances. Prolongs APD and therefore QT interval by blocking outward potassium currents during phase 3 of AP, prolonging repolarization.
Eplerenone
A newer, more selective aldosterone antagonist with fewer endocrine side effects than spironolactone. By competitively inhibiting aldosterone, eplerenone blocks aldosterone’s detrimental cardiac remodeling and fibrosis effects.
Arsenic
Inhibits lipoic acid. Sx. vomiting, rice water stools, garlic breath.
Fomepizole
Inhibits alcohol dehydrogenase, acting as an antidote for methanol or ethylene glycol poisoning
Disulfiram
“Antabuse”. Inhibits acetaldehyde dehydrogenase. An increase in acetaldehyde after drinking alcohol leads to an increase in hangover symptoms, which theoretically should make someone less likely to continue abusing alcohol.
Interferon-alpha
- Synthetic IFN-alpha is used in the tx of hairy cell leukemia, condyloma acuminata, hepatitis B and C infection, Kaposi sarcoma, renal cell carcinoma, malignant melanoma.
- IFN-alpha is part of the innate host defense against both RNA and DNA viruses. Interferons alpha and beta are glycoproteins synthesized by virus-infected cells.
- IFN-alpha and -beta act locally on uninfected cells to prime them for viral defense by helping to selectively degrade viral nucleic acid and protein. “Interfere” with viruses.
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Triple combination antiretroviral therapy (HAART)
- 2 NRTIs (or NtRTIs) “backbone” plus a 3rd drug (protease inhibitor, NNRTI, or integrase inhibitor) “base”: eg, Atripla = [efavirenz + tenofovir + emtricitabine].
- Current US DHHS preferred initial regimens for adults and adolescents:
- tenofovir/emtricitabine + raltegravir (integrase inhibitor)
- tenofovir/emtricitabine + dolutegravir (integrase inhibitor)
- abacavir/lamivudine (2 NRTIs) + dolutegravir for patients tested negative for HLA-B*5701 gene allele
- tenofovir/emtricitabine + elvitegravir (integrase inhibitor) + cobicistat (inhibiting hepatic metabolism of elvitegravir) in patients with good kidney function (gfr > 70); Genvoya = [elvitegravir + cobicistat + emtricitabine + tenofovir]
- tenofovir/emtricitabine + ritonavir + darunavir (both protease inhibitors)
- In protease inhibitor based regimens, ritonavir is used at low doses to inhibit cytochrome p450 enzymes and “boost” levels of other protease inhibitors, rather than for direct antiviral effect.
- Cobicistat used with elvitegravir for similar effect but has no direct antiviral effect itself.
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Mechanism of resistance in Vancomycin Resistant Enterococcus (VRE)
Change in peptide precursor structure that alters vancomycin-binding site from D-alanyl-D-alanine terminus to a D-alanine-D-lactate terminus, preventing vancomycin from binding to its usual site.
Penicillin resistance mechanisms
- Bacteria that produce beta-lactamase (penicillinase) are able to destroy beta-lactam ring of penicillins and render them ineffective.
- Cephalosporins, carbapenems, and penicillinase-resistant penicillins (nafcillin, methicillin) are not susceptible to beta-lactamase.
- Some bacteria (MRSA) have modified the penicillin binding proteins (PBPs) in their peptidoglycan cell walls so that beta-lactam antibiotics are unable to bind and interfere with cell wall synthesis.
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Polymyxin
Antibiotic that binds to, disrupts, and interferes with the permeability of the cytoplasmic membrane.
Tetracycline resistance
Mechanisms of tetracycline resistance include an increased efflux of the drug from within the bacterial cell via an active efflux pump or production of a protein that allows translation to take place even with tetracycline present.
Sulfonamides and Trimethoprim (eg, SMP-TMX)
- Sulfonamides (sulfamethoxazole, sulfadiazine) are structural analogues of PABA, a precursor for dihydrofolic acid.
- High levels of PABA analogue competitively inhibit dihydropteroate synthase (DHPS), an enzyme needed to form dihydrofolic acid and therefore folic acid synthesis.
- Trimethoprim inhibits bacterial dihydrofolate reductase, the enzyme needed to create THF. (MTX inhibits DHFR in humans, pyrimethamine in protozoa).
- Inhibition of folic acid synthesis results in disruption of DNA synthesis and inhibition of bacterial growth.
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Nucleoside Reverse Transcriptase Inhibitors (NRTIs)
- zidovudine (AZT or ZDV) - thymidine analog
- didanosine (ddI) - adenosine analog
- zalcitabine (ddC) - cytidine analog, d/c’d by drug company
- lamivudine (3TC) - cytidine analog, also used in chronic hepatitis B tx
- stavudine (d4T) - thymidine analog
- emtricitabine (FTC) - cytidine analong
- abacavir (ABC) - guanosine analog
- entecavir (ETV) - guanosine analog, only approved for hepatitis B tx not HIV
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NRTI and NtRTI mechanism of action
- Competitively inhibit HIV reverse transcriptase.
- Compete with nucleotide triphosphates (eg, dATP, dCTP) to be added to newly synthesized viral DNA strand.
- Prior to incorporation into viral DNA, NRTIs must be phosphorylated to form NRTI triphosphates. Phosphorylation carried out by cellular kinase enzymes.
- Unlike natural deoxynucleotides, NRTIs and NtRTIs lack a 3′-hydroxyl group on deoxyribose moiety.
- After incorporation of NRTI or NtRTI, next incoming deoxynucleotide cannot form a 5′–3′ phosphodiester bond needed to extend the DNA chain.
- Thus, incorporation of NRTI or NtRTI halts viral DNA synthesis in a process known as chain termination.
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Side effects of NRTIs
- All NRTIs- neutropenia (bone marrow suppression that can be reversed with granuloctye colony-stimulating factor G-CSF and erythropoietin), hypersensitivity reactions (rash), GI upset, lactic acidosis
- zidovudine (AZT/ZDV)- megaloblastic anemia
- didanosine (ddI)- pancreatitis
- zalcitabine (ddC), stavudine (d4T)- peripheral neuropathy
- abacavir (ABC)- lactic acidosis, contraindicated if patient has HLA-B5701 mutation
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Zidovudine (AZT/ZDV)
Use of AZT during pregnancy and in neonates with HIV+ mothers has been shown to significantly reduce the risk of viral transmission from mother to child. Can be used as general prophylaxis. Side effects of AZT- neutropenia, rash, GI upset, megaloblastic anemia.
Nucleotide analogue reverse transcriptase inhibitors (NtRTIs)
- Tenofovir (TDF) - adenosine analog, approved for HIV and HBV tx
- Adefovir - adenosine analog, lower dose approved for chronic Hepatitis B tx, not approved for HIV 2/2 to toxicity issues with high dose
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Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)
- Efavirenz
- Nevirapine
- Delavirdine
- Etravirine (new)
- Rilpivirine (new)
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NNRTI mechanism of action
- NNRTIs block HIV reverse transcriptase by binding directly at a specific site.
- Not incorporated into viral DNA like NRTIs and do not require phosphorylation to be active.
- Inhibit movement of protein domains of reverse transcriptase needed to carry out the process of DNA synthesis.
- NNRTIs are therefore classified as non-competitive inhibitors of reverse transcriptase.
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Side effects of NNRTIs
- Efavirenz- CNS disturbances (insomnia, dizziness, delusions, vivid nightmares), rash, hepatotoxicity, teratogenic (contraindicated in pregnancy)
- Nevirapine - SJS (rash), fulminant hepatitis (hepatotoxicity), induction of cytochrome P450 resulting in increased metabolism of several drugs (OCPs, warfarin, metronidazole, ketoconazole, some protease inhibitors)
- Delaviridine - headache, fatigue, nausea, rash, elevated LFTs, teratogenic (contraindicated in pregnancy)
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Protease inhibitors mechanism of action
- Inhibit HIV protease enzyme, responsible for cleaving precursor proteins into mature proteins involved in forming core of viral particle.
- Assembly of virions depends on HIV-1 protease (pol gene), which cleaves polypeptide products of HIV mRNA into their functional parts.
- Thus, protease inhibitors prevent maturation of new viruses and the virus is UNABLE TO REPLICATE.
- All protease inhibitor names end in -navir.
- Rifampin is a potent CYP/UGT inducer and is contraindicated with protease inhibitors as it can decrease their concentration.
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Protease inhibitors
- Atazanavir
- Darunavir
- Fosamprenavir- superceded Amprenavir
- Indinavir - “Crix belly”
- Lopinavir - combo with ritonavir
- Ritonavir - can boost other drug concentrations by inhibiting cytochrome P450.
- Saquinavir - first approved ever
- Nelfinavir
- Tipranavir
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Integrase inhibitors
- Raltegravir
- Elvitegravir
- Dolutegravir
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Integrase inhibitors mechanism of action
Inhibit HIV genome integration into host cell chromosome by reversibly inhibiting HIV integrase. Side effects: increase in creatine kinase
Side effects of Protease Inhibitors
- All protease inhibitors - lipodystrophy (Cushing-like syndrome of altered distribution of body fat causing a buffalo hump or truncal obesity), insulin resistance, hyperglycemia, hyperlipidemia, GI intolerance (nausea, diarrhea).
- Ritonavir, nelfinavir- paresthesias
- Indinavir- elevated bilirubin, kidney stones, nephropathy, hematuria
- Ritonavir- inhibits cyt P450 leading to increased serum levels of drugs (eg, other protease inhibitors, ketoconazole, rifampin, erythromycin, some anti-arrhythmics, benzodiazepines, slozapine, fluoxetine, haloperidol.)
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HAART
Highly active antiretroviral therapy often initiated at time of HIV diagnosis. Strongest indication for patients presenting with AIDS-defining illness, low CD4+ cell counts (less than 500) or high viral load. Regimen consists of 3 drugs to prevent resistance: 2 NRTIs and preferably an integrase inhibitor.
Fusion inhibitors
- Enfuvirtide- binds gp41, inhibiting viral entry/penetration into the cell. Skin reaction at injection sites.
- Maraviroc- binds CCR-5 on surface of T cells/monocytes, inhibiting interaction with gp120 and thus inhibiting attachment of the virion.
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Acyclovir
- Acyclovir, famciclovir, valacyclovir, penciclovir.
- Guanosine analogs that are monophosphorylated by viral thymidine kinase. Not phosphorylated in uninfected cells, causing few adverse effects. Triphosphate formed by cellular enzymes. Once phosphorylated, dGTP analogs preferentially inhibit viral DNA polymerase by chain termination.
- Active against HSV-1, HSV-2, VZV (famciclovir), weakly against EBV.
- Not active against CMV.
- Tx mucocutaneous/genital herpes, herpes encephalitis, acute VZV infection, and oral hairy leukoplakia (assoc with EBV infection). Prophylaxis in immunocompromised patients.
- No effect on latent HSV/VZV.
- Valacyclovir (prodrug of acyclovir) has better oral bioavailability.
- Resistance to acyclovir if virus has mutated viral thymidine kinase.
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