Three products are currently available in the US for treatment of high-risk,1 nonhospitalized adults with mild to moderate COVID-19: oral ritonavir-boosted nirmatrelvir (Paxlovid), IV remdesivir (Veklury), and oral molnupiravir (Lagevrio). Remdesivir is FDA-approved for such use; nirmatrelvir/ritonavir and molnupiravir are available under an FDA Emergency Use Authorization. Because the pivotal clinical trials of these products for outpatient use were conducted in patients who were not vaccinated against COVID-19, some clinicians have questioned whether they can benefit vaccinated outpatients.

The FDA has withdrawn its Emergency Use Authorization (EUA) of the investigational anti-SARS-CoV-2 monoclonal antibody bebtelovimab (LY-CoV1404 – Lilly) for treatment of COVID-19. Bebtelovimab is not expected to retain activity against the Omicron variants BQ.1 and BQ.1.1, which currently cause the majority of COVID-19 cases in all regions of the US.

The FDA has amended its Emergency Use Authorization (EUA) for Paxlovid (Pfizer), the investigational oral antiviral drug nirmatrelvir copackaged with oral ritonavir, to allow for it to be prescribed by licensed pharmacists in certain situations. Paxlovid is authorized for oral treatment of mild to moderate COVID-19 in high-risk outpatients ≥12 years old who weigh at least 40 kg. NIH guidelines list it as the treatment of choice for COVID-19 in high-risk adult outpatients.

On April 29, the NIH recommended against use of the antiparasitic drug ivermectin for treatment of COVID-19 outside of a clinical trial. The recommendation was made because recent randomized, placebo-controlled trials of ivermectin have produced negative results and because alternative drugs that have been shown to be effective for treatment of COVID-19 are available.

The FDA has expanded the Emergency Use Authorizations (EUAs) for the mRNA COVID-19 vaccines manufactured by Pfizer-BioNTech (Comirnaty) and Moderna (Spikevax) to allow for their use as a second booster dose ≥4 months after a first booster dose in adults ≥50 years old and in persons aged ≥12 years (Pfizer) or ≥18 years (Moderna) who have undergone solid organ transplantation or have a condition that compromises the immune system to a similar extent.

The investigational monoclonal antibody bebtelovimab (LY-CoV1404 – Lilly) has been granted an FDA Emergency Use Authorization (EUA) for IV treatment of mild to moderate COVID-19 in patients ≥12 years old who weigh ≥40 kg and are at high risk of progressing to severe disease, including hospitalization and death, and for whom alternative treatment options are unavailable or inappropriate. Bebtelovimab is active against the Omicron variant of SARS-CoV-2; sotrovimab (VIR-7831) is the only other monoclonal antibody currently available for treatment of COVID-19 that is active against Omicron.

The IV antiviral drug remdesivir (Veklury – Gilead) has been available for treatment of COVID-19 in hospitalized patients since 2020. Now, the FDA has approved remdesivir for treatment of mild to moderate COVID-19 in outpatients ≥12 years old who weigh ≥40 kg and are at high risk for progression to severe disease, including hospitalization or death; they also issued an Emergency Use Authorization (EUA) allowing its use in any other high-risk outpatient who weighs ≥3.5 kg.

View the Treatment of COVID-19 in High-Risk Outpatients Chart

On December 22, 2021, the FDA issued an Emergency Use Authorization (EUA) for the investigational antiviral drug nirmatrelvir copackaged with the HIV-1 protease inhibitor ritonavir (Paxlovid – Pfizer) for oral treatment of mild to moderate COVID-19 in outpatients ≥12 years old who weigh at least 40 kg and are at high risk of progressing to severe disease, including hospitalization or death. Paxlovid was the first oral antiviral drug to be authorized in the US for treatment of COVID-19; Merck's oral antiviral drug molnupiravir was granted an EUA for treatment of COVID-19 on December 23, 2021. The IV antiviral drug remdesivir (Veklury) was approved by the FDA in 2020 for treatment of COVID-19 in hospitalized patients.

The FDA has approved Twirla (Agile Therapeutics), a transdermal contraceptive patch containing the estrogen ethinyl estradiol and the progestin levonorgestrel, for use in women with a BMI <30 kg/m². It is the second contraceptive patch to become available in the US; Xulane, a patch that delivers ethinyl estradiol and the progestin norelgestromin, has been available since 2014.

The severity and rapid spread of COVID-19 (caused by SARS-CoV-2) have raised questions about the use of some drugs in patients with the disease and whether currently available drugs could be effective in treating it. Definitive answers are lacking, but some recommendations can be made. For additional information on specific drugs, see our table Some Drugs Being Considered for Treatment of COVID-19.

View the Table: Treatments Considered for COVID-19

The severity and rapid spread of COVID-19 (caused by SARS-CoV-2) have raised questions about the use of some drugs in patients with the disease and whether currently available drugs could be effective in treating it. Definitive answers are lacking, but some recommendations can be made. For additional information on specific drugs, see our table Some Drugs Being Considered for Treatment of COVID-19.

Annovera (TherapeuticsMD), a contraceptive vaginal ring that releases segesterone acetate, a synthetic progestin, and ethinyl estradiol, was approved by the FDA in 2018 and is now available. It is the first product to contain segesterone and the second vaginal ring to become available in the US; NuvaRing, which delivers etonogestrel and ethinyl estradiol, was the first. Unlike NuvaRing, which requires use of a new ring each month, the Annovera ring can be used for an entire year, but it must be removed for one week each month.

The FDA has approved three new once-daily fixed-dose antiretroviral drug combinations for treatment of HIV-1 infection. Symfi and Symfi Lo (Mylan) contain the non-nucleoside reverse transcriptase inhibitor (NNRTI) efavirenz and the nucleoside reverse transcriptase inhibitors (NRTIs) lamivudine and tenofovir disoproxil fumarate (TDF) and were approved as complete antiretroviral regimens. Symfi Lo contains a lower dose of efavirenz than both Symfi and Atripla, a fixed-dose combination of efavirenz, TDF, and the NRTI emtricitabine that was approved in 2006. Cimduo (Mylan), which contains lamivudine and TDF, was approved for use in combination with other antiretroviral drugs. All three new products are marketed as less expensive alternatives to other available fixed-dose antiretroviral combinations (see Table 1).

The FDA recently announced that it will require the labeling of all direct-acting antiviral drugs used for treatment of hepatitis C virus (HCV) infection to include a boxed warning about a risk of hepatitis B virus (HBV) reactivation associated with their use.1

Twenty-four cases of HBV reactivation occurring during treatment with direct-acting antiviral drugs for HCV were identified from the FDA Adverse Event Reporting System and the medical literature.2-5 Before starting direct-acting antiviral treatment for HCV, some of these patients were hepatitis B surface antigen (HbsAG) positive and others showed evidence of resolved HBV infection. HBV reactivation generally occurred within 4-8 weeks of starting treatment. Reactivation of HBV can cause increases in bilirubin and aminotransferase levels, fulminant hepatitis, hepatic failure, and death. Of the 24 patients, two died and one required a liver transplant.

HBV reactivation was not identified before FDA approval of these drugs because the clinical trials used to support their approval excluded patients with HBV co-infection. The mechanism by which HBV reactivation occurs during treatment with direct-acting antiviral drugs for HCV is unknown. Patients should be screened for current or past HBV infection before starting treatment with a direct-acting antiviral and monitored for HBV reactivation during and following treatment with these drugs.

1. FDA Drug Safety Communication: FDA warns about the risk of hepatitis B reactivating in some patients treated with direct-acting antivirals for hepatitis C. Available at: www.fda.gov. Accessed October 13, 2016.
2. JM Collins et al. Hepatitis B virus reactivation during successful treatment of hepatitis C virus with sofosbuvir and simeprevir. Clin Infect Dis 2015; 61:1304.
3. A De Monte et al. Direct-acting antiviral treatment in adults infected with hepatitis C virus: reactivation of hepatitis B virus coinfection as a further challenge. J Clin Virol 2016; 78:27.
4. AR Ende et al. Fulminant hepatitis B reactivation leading to liver transplantation in a patient with chronic hepatitis C treated with simeprevir and sofosbuvir: a case report. J Med Case Rep 2015; 9:164.
5. C Wang et al. Hepatitis due to reactivation of hepatitis B virus in endemic areas among patients with hepatitis C treated with direct-acting antiviral agents. Clin Gastroenterol Hepatol 2016 July 5 (epub).

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The FDA has approved Epclusa (Gilead), a fixed-dose combination of sofosbuvir (Sovaldi) and velpatasvir, a new direct-acting antiviral agent, for oral treatment of chronic hepatitis C virus (HCV) infection. Epclusa is the first oral combination to be approved for treatment of all six major HCV genotypes.

The FDA has approved Zepatier (Merck), a fixed-dose combination of two direct-acting antiviral agents — elbasvir, an NS5A inhibitor, and grazoprevir, an NS3/4A protease inhibitor — for oral treatment of chronic hepatitis C virus (HCV) genotype 1 or 4 infection.

The FDA has approved elvitegravir (Vitekta – Gilead), an integrase strand transfer inhibitor (INSTI), for use with a protease inhibitor (PI) plus ritonavir and other antiretroviral drugs for treatment of HIV-1 infection in treatment-experienced adults. Elvitegravir is also available in a fixed-dose combination (Stribild) with the pharmacokinetic enhancer cobicistat and the nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) emtricitabine and tenofovir disoproxil fumarate (DF). A similar combination (Genvoya) that includes tenofovir alafenamide instead of tenofovir DF was recently approved by the FDA and will be reviewed in a future issue.

Cobicistat, a pharmacokinetic enhancer that boosts levels of some HIV drugs but has no antiretroviral activity of its own, is now available alone as Tybost (Gilead) and in fixed-dose combinations with the protease inhibitors atazanavir (Evotaz — BMS) and darunavir (Prezcobix — Janssen) for treatment of HIV-1 infection. Both atazanavir and darunavir have traditionally been used in combination with the CYP3A inhibitor ritonavir (Norvir) to boost their serum concentrations, but neither is available in a fixed-dose combination with ritonavir.

The FDA has approved Technivie (Abbvie), a fixed-dose combination of the direct-acting antiviral agents ombitasvir and paritaprevir and the pharmacokinetic enhancer ritonavir, for oral treatment of chronic hepatitis C virus (HCV) genotype 4 infection in patients without cirrhosis. It is indicated for use in combination with ribavirin. Ombitasvir/paritaprevir/ritonavir copackaged with dasabuvir, an HCV RNA polymerase inhibitor that has little activity against HCV genotype 4, is approved as Viekira Pak for treatment of HCV genotype 1 infection.1

HCV genotype 4 is uncommon in the US and Canada. It is the most prevalent strain of HCV in Central sub-Saharan Africa, North Africa, and the Middle East.2 Technivie plus ribavirin was the first all-oral treatment approved for treatment of HCV genotype 4. Ledipasvir/sofosbuvir (Harvoni)3 was also recently approved for this indication; it does not require coadministration with ribavirin and can be used in patients with or without cirrhosis. Its use for this and other new indications will be reviewed in a future issue.

FDA approval of Technivie was based on an open-label trial (PEARL-I) in 86 treatment-naive and 49 treatment-experienced non-cirrhotic patients with HCV genotype 4 infection. Treatment-naive patients were randomized to receive Technivie with or without ribavirin for 12 weeks; all treatment-experienced patients received the combination plus ribavirin for 12 weeks. The rate of sustained virologic response 12 weeks after stopping treatment (SVR12), the primary endpoint, was 91% (40/44) in treatment-naive patients not receiving ribavirin and was 100% in both treatment-naive (42/42) and treatment-experienced (49/49) patients receiving the combination plus ribavirin.4

Adverse effects observed with Technivie in the clinical trial included asthenia, fatigue, nausea, insomnia, pruritus, and skin reactions. Like Viekira Pak, Technivie has been associated with serious, sometimes fatal cases of hepatic decompensation and is contraindicated in patients with moderate to severe (Child-Pugh B/C) hepatic impairment.5 It is also contraindicated in patients taking ethinyl estradiol (because of a risk of ALT elevation), CYP3A4 inducers such as rifampin, or certain sensitive CYP3A4 substrates such as midazolam or simvastatin.6

Each Technivie tablet contains 12.5 mg of ombitasvir, 75 mg of paritaprevir, and 50 mg of ritonavir. The recommended dosage is two tablets taken once daily in the morning with a meal for 12 weeks. Ribavirin should be coadministered with Technivie at a daily dose of 1000 mg in patients weighing <75 kg or 1200 mg in those weighing ≥75 kg. Use of Technivie alone may be considered in treatment-naive patients who cannot take or tolerate ribavirin. A 12-week supply of Technivie costs $76,653.7

1. A 4-drug combination (Viekira Pak) for hepatitis C. Med Lett Drugs Ther 2015; 57:15.
2. JP Messina et al. Global distribution and prevalence of hepatitis C virus genotypes. Hepatology 2015; 61:77.
3. A combination of ledipasvir plus sofosbuvir (Harvoni) for hepatitis C. Med Lett Drugs Ther 2014; 56:11.
4. C Hézode et al. Ombitasvir plus paritaprevir plus ritonavir with or without ribavirin in treatment-naive and treatment-experienced patients with genotype 4 chronic hepatitis C virus infection (PEARL-I): a randomised, open-label trial. Lancet 2015; 385:2502.
5. In brief: hepatic injury with hepatitis C drugs. Med Lett Drugs Ther 2015; 57:156.
6. Inhibitors and inducers of CYP enzymes and P-glycoprotein. Med Lett Drugs Ther 2013; 55:e44.
7. Approximate WAC. WAC = wholesaler acquisition cost or manufacturer's published price to wholesalers; WAC represents a published catalogue or list price and may not represent an actual transactional price. Source: AnalySource® Monthly. November 5, 2015. Reprinted with permission by First Databank, Inc. All rights reserved. ©2015 www.fdbhealth.com/policies/drug-pricing-policy.

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The FDA recently announced labeling changes for the combination antiviral products Viekira Pak (ombitasvir/paritaprevir/ritonavir with dasabuvir)1 and Technivie (ombitasvir/paritaprevir/ritonavir)2 warning of a risk of serious, potentially fatal liver injury.3 Viekira Pak, approved in December 2014 for treatment of hepatitis C virus (HCV) genotype 1 infection, including patients with compensated cirrhosis, and Technivie, approved in July 2015 for treatment of HCV genotype 4 infection without cirrhosis, have been identified as "possible" or "probable" causes in 26 postmarketing cases of hepatic decompensation, including 10 cases (mostly in patients with preexisting advanced cirrhosis) that resulted in death or liver transplant. Hepatic injury generally occurred within 1-4 weeks of treatment initiation.

All therapies for chronic HCV infection have been associated with cases of hepatic decompensation in patients with advanced fibrosis or cirrhosis, but cause and effect are difficult to determine. Viekira Pak and Technivie are now contraindicated in patients with moderate to severe (Child-Pugh B/C) hepatic impairment. Ledipasvir/sofosbuvir (Harvoni), another recently approved treatment for HCV genotype 1 infection,4 is still indicated for treatment of patients with any degree of compensated hepatic impairment (Child-Pugh A/B/C). The efficacy and safety of all three combinations in patients with decompensated cirrhosis have not been established.

1. A 4-drug combination (Viekira Pak) for hepatitis C. Med Lett Drugs Ther 2015; 57:15.
2. In brief: Technivie for HCV genotype 4 infection. Med Lett Drugs Ther 2015; in press.
3. FDA Drug Safety Communication: FDA warns of serious liver injury risk with hepatitis C treatments Viekira Pak and Technivie. Available at: www.fda.gov. Accessed October 29, 2015.
4. A combination of ledipasvir and sofosbuvir (Harvoni) for hepatitis C. Med Lett Drugs Ther 2014; 56:111.

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The FDA has approved Viekira Pak (Abbvie), a fixed-dose combination of two new direct-acting antiviral agents (ombitasvir, paritaprevir) with the pharmacologic enhancer ritonavir in one tablet, co-packaged with a third new direct-acting antiviral agent (dasabuvir) in a second tablet, for oral treatment of chronic hepatitis C virus (HCV) genotype 1 infection. Genotype 1 is responsible for 70-80% of HCV infections in the US.

The FDA has approved Triumeq (Viiv Healthcare), a fixed-dose combination of the integrase strand transfer inhibitor (INSTI) dolutegravir and the nucleoside reverse transcriptase inhibitors (NRTIs) abacavir and lamivudine, for once-daily treatment of HIV-1 infection. Dolutegravir (Tivicay) was approved as a single agent in 2013.

Antiretroviral therapy is recommended for all HIV-infected patients, both to reduce the risk of disease progression and to prevent transmission of the virus to others. Various guidelines for treatment of HIV infection are available.

The FDA has approved dolutegravir (doll-you-TEG-rah-veer; Tivicay – Viiv Healthcare), an integrase strand transfer inhibitor (INSTI), for treatment of HIV-1 infection in adults and in children ≥12 years old who weigh at least 40 kg. It is the third INSTI to be approved by the FDA; raltegravir and elvitegravir were approved earlier.

Tuberculosis (TB) is still a common cause of death worldwide, and the prevalence of drug-resistant TB poses challenges to its treatment and control. Guidelines with detailed management recommendations are available from the American Thoracic Society, Centers for Disease Control and Prevention (CDC) and Infectious Diseases Society of America (IDSA).

The FDA has approved tesamorelin (Egrifta – EMD Serono), an injectable synthetic analog of growth-hormone- releasing factor (GRF), for reduction of excess abdominal fat in patients with lipodystrophy associated with HIV infection. Growth hormone (somatropin – Serostim; EMD Serono) has been available for years for treatment of HIV wasting.

Even though the incidence continues to decline in the United States, tuberculosis (TB) is still a common cause of death worldwide, and the prevalence of drug-resistant TB poses severe challenges to its treatment and control. Guidelines with detailed management recommendations are available from the Centers for Disease Control and Prevention (CDC), American Thoracic Society and Infectious Diseases Society of America (IDSA).

Primary hypothyroidism is usually the result of Hashimoto's thyroiditis, thyroidectomy for hyperthyroidism, goiter or cancer, or radioactive iodine therapy for hyperthyroidism.

New guidelines for use of antiretroviral agents have been published, with a shift towards earlier and more continuous treatment. HIV infection is treated with combinations of antiretroviral drugs depending on the patientÆs HIV RNA levels ("viral load") and CD4 cell count. Increases in viral load while on therapy may indicate development of drug resistance, requiring further testing and a change in treatment regimen. Resistance testing is now recommended when a patient is first seen, regardless of when therapy will be started.

A recent letter to the editor of the Annals of Internal Medicine documented a single case of myopathy apparently due to an interaction between simvastatin (Zocor, and others) and green tea. Since it became available generically, simvastatin has surpassed atorvastatin (Lipitor) as the best selling statin. As such, it is probably the most common cause of statin-induced myopathy, which is often a result of drug interactions.

Etravirine (Intelence - Tibotec), a new non-nucleoside reverse transcriptase inhibitor (NNRTI), has received fast-track FDA approval for use in combination therapy in treatment-experienced adults who have HIV-1 infection resistant to an NNRTI and other antiretroviral agents.

The drugs of choice for treatment of some fungal infections are listed in the tables. Some of the indications and dosages recommended here have not been approved by the FDA. Other guidelines are available from the Infectious Diseases Society of America (www.idsociety.org).

The approval of new drugs and continuing concerns about drug toxicity and resistance have prompted new antiretroviral treatment guidelines. Resistance testing is not recommended before starting antiretroviral therapy. HIV infection is treated with combinations of antiretroviral drugs while monitoring the patient's HIV RNA levels ("viral load") and CD4 cell count. Increases in viral load while on therapy may indicate development of drug resistance requiring further testing and a change in treatment regimen.

Darunavir (Prezista - Tibotec), a new protease inhibitor, has received accelerated approval from the FDA for use in combination therapy of human-immunodeficiency virus (HIV) infection in previously treated adults. It is coadministered with low-dose ritonavir (Norvir), which increases its bioavailability.

Tipranavir (Aptivus - Boehringer Ingelheim), a new protease inhibitor, has received accelerated approval from the FDA. It must be given with ritonavir (Norvir). The combination is indicated for use with other antiretrovirals to treat HIV infection in highly treatment-experienced adults who have ongoing viral replication or in those with HIV strains known to be resistant to multiple protease inhibitors.

Serious adverse interactions between drugs continue to be reported. Many of these are due to inhibition or induction of cytochrome P450 (CYP) enzymes, particularly CYP3A4. CYP3A is thought to be involved in the metabolism of more than 50 percent of currently prescribed drugs.2 CYP3A4, which is more abundantly expressed than CYP3A5, accounts for most CYP3A activity in vivo.

Erlotinib (Tarceva) is the second oral epidermal growth factor receptor (EGFR) inhibitor to become available in the US for treatment of advanced refractory NSCLC. In clinical trials, erlotinib produced a response rate of only 8.9%, but increased median survival from 4.7 to 6.7 months. Patients who had never smoked and those with EGFR-positive tumors survived longer. Erlotinib is generally well tolerated; diarrhea and rash are the most common adverse effects.

The drugs of choice for treatment of some fungal infections are listed in the table that begins on page 8. Some of the indications and dosages recommended here have not been approved by the FDA.

Alprazolam, a short-acting benzodiazepine, is one of the most widely prescribed drugs in the US. It is approved by the FDA for treatment of anxiety and panic disorder. An extended-release formulation, Xanax XR, which can be taken once a day, recently became available for panic disorder.

Tuberculosis (TB) is still a problem in the United States, even though the incidence continues to decline in most of the country (MMWR Morbid Mortal Wkly Rep 2004; 53:209). Treatment of TB can be divided into treatment of latent infection diagnosed by a positive PPD and treatment of active clinical TB. Guidelines with detailed management recommendations are available from the US Centers for Disease Control and Prevention (CDC) (MMWR Morbid Mortal Wkly Rep 2003; 52RR-11:1).

Drugs for treatment of migraine attacks are listed in the table on page 64. All of the oral drugs are most effective if taken early in an attack when the pain is mild (H Christoph-Diener et al, Neurology 2004; 63:520). Drugs for prevention of migraine are listed in the table on page 65. Treatment of migraine in the emergency room, which may involve use of intravenous drugs, is not included here.

Telithromycin (Ketek - Aventis) has been approved by the FDA for oral treatment of mild to moderate community-acquired pneumonia, acute exacerbations of chronic bronchitis and acute bacterial sinusitis in patients age 18 and older. The drug is the first in a new class of antibiotics, the ketolides, derived from the macrolide erythromycin. Telithromycin has been marketed in Europe since 2001.

Methamphetamine, a highly addictive synthetic sympathomimetic, has again become important as a drug of abuse in the US. Its resurgence has been associated with unsafe sexual practices that have resulted in an increase in HIV transmission, particularly among men who have sex with men (SJ Semple et al, J Subst Abuse Treat 2002; 22:149; A Urbina and K Jones, Clin Infect Dis 2004; 38:890).

Alfuzosin hydrochloride (Uroxatral - Sanofi-Synthelabo) is now available in the US in a new formulation for once-daily treatment of benign prostatic hyperplasia (BPH). The drug has been used in Europe since 1987. Alpha₁-blockers cause relaxation of smooth muscle tone in the bladder neck, prostatic capsule and prostatic urethra, relieving symptoms of urinary obstruction.

New drug approvals as well as continuing concerns about drug toxicity and the development of resistance have prompted new antiretroviral treatment guidelines (Panel on Clinical Practices for Treatment of HIV Infection, November 10, 2003, www.aidsinfo.nih.gov).

Tadalafil (Cialis - Lilly Icos) is the third oral drug to be approved by the FDA for treatment of erectile dysfunction. It has a longer duration of action than sildenafil (Viagra) or vardenafil (Levitra - Medical Letter 2003; 45:77).

Atazanavir (Reyataz - Bristol-Myers Squibb), a new protease inhibitor (PI), and emtricitabine (Emtriva - Gilead), a nucleoside analogue reverse transcriptase inhibitor (NRTI) chemically similar to lamivudine, have been approved by the FDA for treatment of HIV-1 infection. Both are taken once daily, unlike most anti-HIV drugs.

Vardenafil (Levitra -Bayer) is the second oral drug approved by the FDA for treatment of erectile dysfunction. Sildenafil (Viagra - Medical Letter 1998; 40:51), the first oral drug, has been available for 5 years. Pharmacokinetics, effectiveness, adverse effects, dosage and cost of the new drug are reviewed. Whether it offers any benefits over sildenafil is discussed.

Changes caused by one drug in the absorption, distribution, metabolism or excretion of another may lead to a pharmacokinetic adverse drug interaction (DN Juurlink et al, JAMA 2003; 289:1652). Additive drug interactions, such as vasodilation caused by both sildenafil (Viagra) and nitrates, can also have adverse effects.

Eplerenone (e pler' en one; Inspra - Pharmacia), an aldosterone receptor antagonist similar to spironolactone (Aldactone, and others), has been approved by the FDA, but not yet marketed, for treatment of hypertension. It has also been tried for treatment of heart failure.

Eletriptan hydrobromide (Relpax Pfizer) is now available in the US for oral treatment of migraine headache in adults. It is the seventh serotonin 5-HT_1B/1D-receptor agonist (triptan) to be approved by the FDA for this indication. This review describes the pharmacokinetics, adverse effects, drug interactions and recommended dosage of eletriptan. Clinical trials comparing the new drug to placebo and to sumatriptan are presented. A dosage and cost table for all the triptans available in the US is also included. The review concludes with an overall assessment of eletriptan's efficacy and safety.

Since the last Medical Letter article on this subject, continuing concerns about drug toxicity and development of resistance have prompted new antiretroviral treatment guidelines. The dosage and cost of drugs for HIV infection are listed in the table in this article.

Lopinavir/ritonavir is the first fixed-dose combination of protease inhibitors approved by the FDA for the treatment of HIV infection. It is being marketed for use with other drugs in adults and children more than six months old. Lopinavir is a new drug available only in this combination. Ritonavir is often used with other protease inhibitors to raise their plasma concentrations.

Highly active anti-retroviral therapy (HAART) combining three or four drugs has become the standard of care for treatment of human immunodeficiency virus (HIV) infection

Amprenavir is the fifth protease inhibitor to become available for treatment of HIV infection. It was approved by the FDA for use with other drugs in the treatment of HIV-infected adults and children at least four years old.

Reports of adverse interactions between drugs continue to accumulate. Recently, the FDA has expanded the recommendations on drug interactions found in the package inserts of new drugs.

Combination antiretroviral therapy including protease inhibitors has dramatically changed the treatment of HIV infection and the prognosis of those affected (Medical Letter Handbook of Antimicrobial Therapy, 1998, page 122). Due to limitations and failures with these drugs in many patients, however, three new drugs, none of them protease inhibitors, have rapidly come into wide use in clinical trials or 'expanded access' programs. They are abacavir (Ziagen - Glaxo Wellcome), adefovir (Preveon - Gilead) and efavirenz (Sustiva - DuPont). Efavirenz was recently approved for treatment of adults and children by the FDA. Abacavir has been recommended for approval by an FDA advisory committee.

Recent studies have led to changes in the approach to treating human immunodeficiency virus (HIV) infection (CCJ Carpenter et al, JAMA, 277:1962, 1997). None of the drugs currently available to treat HIV-infected patients has been shown to eradicate the infection, but used in combination they can decrease viral replication, improve immunologic status, delay infectious complications and prolong life. The drug regimens recommended by Medical Letter consultants are listed in the table on page 114. Adult regimens and dosages may not be applicable to children (Guidelines for use of Antiretroviral Agents in Pediatric HIV Infection, HIV/AIDS Treatment Information Services, www.hivatis.org/glarvped.html). Some drugs interactions of anti-HIV drugs are listed on the table that begins on page 115.

The drugs of choice for treatment of deep fungal infections are listed in the table below. Some of the indications and dosages recommended here have not been approved by the FDA.

Bupropion hydrochloride, currently available as an antidepressant (Wellbutrin - Medical Letter, 31:97, 1989; Wellbutrin SR), is now being marketed in a sustainedrelease formulation as Zyban (Glaxo Wellcome) for use as an aid in smoking cessation.

Four new drugs have become available in the USA for HIV infection or its complications. Nevirapine (Viramune - Roxane), intravenous cidofovir (Vistide - Gilead), and amphotericin B oral suspension (Fungizone Oral Suspension - Bristol-Myers Squibb) have been approved by the US Food and Drug Administration; nelfinavir (Viracept - Agouron) is currently available only through an "Expanded Access Program."

The US Food and Drug Administration (FDA) has approved the marketing of five new drugs for treatment of HIV Infection. Stavudine (D4T; Zerit - Bristol-Myers Squibb) and lamivudine (3TC; Epivir - Glaxo Wellcome) are nucleoside analogs similar to zidovudine (AZT), didanosine (ddl) and zalcitabine (ddC). Saquinavir (Invirase - Roche), ritonavir (Norvir - Abbott) and indinavir (Crixivan - Merck) are protease inhibitors, a new class of anti-HIV drugs.