Delavirdine (Rescriptor)

What Is Delavirdine?

Delavirdine is a drug used as part of antiretroviral therapy (ART). It is also called Rescriptor^®. Pharmacia & Upjohn developed it. Agouron Pharmaceuticals, a Pfizer company, is marketing it.

Delavirdine is a non-nucleoside reverse transcriptase inhibitor (a "non-nuke" or NNRTI). These drugs stop HIV from multiplying by preventing the reverse transcriptase enzyme from working. This enzyme changes HIV's genetic material (RNA) into DNA. This has to occur before HIV's genetic code gets combined with an infected cell's genetic codes.

Who Should Take It?

Delavirdine was approved in 1997 as an antiretroviral drug (ARV) for people with HIV infection. The safety and effectiveness of delavirdine have not been shown for people younger than 16 years old. Delavirdine is inconvenient because it is taken three times a day. It also interacts with some protease inhibitors, changing their blood levels. For these reasons it is not used much any more.

There are no absolute rules about when to start ART. You and your health care provider should consider your CD4 cell count, your viral load, any symptoms you are having, and your attitude about taking ART. Fact Sheet 404 has more information about guidelines for the use of ART.

If you take delavirdine with other ARVs, you can reduce your viral load to extremely low levels, and increase your CD4 cell counts. This should mean staying healthier longer.

What About Drug Resistance?

Many new copies of HIV are mutations. They are slightly different from the original virus. Some mutations can keep multiplying even when you are taking an ARV. When this happens, the drug will stop working. This is called "developing resistance" to the drug. See Fact Sheet 126 for more information on resistance.

Sometimes, if your virus develops resistance to one drug, it will also have resistance to other ARVs. This is called "cross-resistance." Cross-resistance among NNRTIs develops very easily. If you develop resistance to one NNRTI, you probably won't be able to use any of them in your ART.

Resistance can develop quickly. It is very important to take ARVs according to instructions, on schedule, and not to skip or reduce doses.

How Is It Taken?

Delavirdine is available in pills of 100 milligrams (mg) or 200 mg. The recommended dose for adults is 400 mg three times a day. This would be a daily total of 6 of the 200 mg pills, or 12 of the 100 mg pills. You can dissolve the 100 mg pills (but not the 200 mg pills) in water to make them easier to swallow.

Delavirdine can be taken with or without food.

What Are the Side Effects?

When you start any ART, you may have temporary side effects such as headaches, high blood pressure, or just feeling ill. These side effects usually get better or disappear over time.

The most common side effect is a skin rash, which develops in about 25 percent of people taking the drug. The risk of the rash can be reduced if you start taking the drug at a lower dose and then increase to the full dose.

How Does It React With Other Drugs?

Delavirdine is broken down by the liver and can interact with other drugs that also use the liver. Combining these drugs can change the amount of each drug in your bloodstream and cause an under- or overdose.

Drugs to watch out for include other ARVs, drugs to treat tuberculosis (see Fact Sheet 518), for erectile dysfunction (such as Viagra), for heart rhythm (antiarrhythmics), and for migraine headaches. Interactions are also possible with several antihistamines (allergy medications), sedatives, drugs to lower cholesterol, and anti-fungal drugs. Make sure that your health care provider knows about ALL drugs and supplements you are taking.

Blood levels of delavirdine may be decreased by ddI, antacids, rifabutin, and rifampin. Be sure to take delavirdine at least one hour apart from ddI or antacids.

Delavirdine should not be combined with fosamprenavir.

Delavirdine may increase the blood levels of methadone. Delavirdine can increase buprenorphine levels. Watch for signs of increased sedation.

The herb St. John's Wort (See Fact Sheet 729) lowers the blood levels of some nonnucleoside reverse transcriptase inhibitors. Do not take it with delavirdine.