Abstracts

Aspirin (Shingles)

Aspirin

Two aspirins are crushed into a fine powder and placed into 15-30 ml of chloroform. The well mixed suspension is applied to the painful area by utilizing a sterile "cotton" ball. As the chloroform evaporates the powdered "aspirin" sticks to the "skin".

"Topic Aspirin For Herpes Zoster", Gooding, John, M., DO, February 1991;86/36-31.

Capsaicin (Shingles)

Capsaicin

Capsaicin, the active principle of hot chili pepper, is thought to selectively stimulate unmyelinated C fibre afferent neurons and cause the release of substance P. Prolonged application of capsaicin reversibly depletes stores of substance P, and possibly other neurotransmitters, from sensory nerve endings. This reduces or abolishes the transmission of painful stimuli from the peripheral nerve fibres to the higher centres.

In clinical studies of patients with post-hepatic neuralgia, diabetic neuropathy or osteoarthritis, adjunctive therapy with topical capsaicin achieved better relief than its vehicle in most studies.

In a single trial, topical capsaicin in demonstrated similar efficacy to oral amitriptyline in patients with diabetic neuropathy. Topical capsaicin is not associated with any severe systemic adverse effects. However, stinging and burning, particularly during the first week of therapy, is reported by many patients. Topical capsaicin merits consideration as adjuvant therapy in conditions such as post-herpetic neuralgia, diabetic neuropathy and osteoarthritis, where the pain can be chronic and difficult to treat.

Rains C & Bryson HM: Topical capsaicin. A review of its pharmacological properties and therapeutic potential in post-herpetic neuralgia, diabetic neuropathy and osteoarthritis. Drugs Aging, 1995 Oct, 7:4, 317-28.

Elderly (Shingles)

Elderly

Described 3 cases of disseminated herpes zoster occurring in the elderly, and discuss the investigation and diagnosis of this condition.

The presentation may be atypical with excoriated papular lesions.

Suggest that disseminated herpes zoster does occur in the non-immunocompromised elderly patient, and is sometimes overlooked.

O'Toole EA et al., Disseminated herpes zoster in the elderly. Ir J Med Sci, 1997 Jul-Sep, 166:3, 141-2.

Lithium (Shingles)

Lithium

A 42-year-old woman was admitted to the hospital to receive intravenous acyclovir for a herpes zoster infection. At the time she was taking lithium carbonate 450 mg twice/day. Six days after starting acyclovir she exhibited signs of lithium toxicity. When measured, the serum lithium level had increased 4-fold during acyclovir therapy.

Both agents are excreted by the kidneys, raising the possibility that acyclovir at high serum concentrations may interfere with the renal excretion of lithium.

Recommend closely monitoring patients for signs of lithium toxicity and measuring serum lithium levels every second or third day.

Sylvester RK et al., Does acyclovir increase serum lithium levels? Pharmacotherapy, 1996 May-Jun, 16:3, 466-8.

Pharmaceutical Management

Pharmaceutical Management

Herpes simplex virus and varicella-zoster virus are common infections and are seen frequently in clinical practice. Infection with these viruses results in cutaneous lesions that may be diagnosed clinically, but widely available laboratory testing is useful for confirmation. Asymptomatic herpes simplex virus shedding, or "subclinical reactivation," likely occurs in all persons infected with herpes simplex virus and results in the transmission of virus despite the absence of signs or symptoms that suggest active infection. Oral and intravenous acyclovir are effective in treating initial and recurrent herpes simplex and varicella-zoster virus infections.

Two new antiviral agents, famciclovir and valacyclovir hydrochloride, have been approved for the short-term treatment of recurrent genital herpes simplex virus and recurrent zoster in nonimmunocompromised hosts. Famciclovir and valacyclovir demonstrate superior pharmacokinetics compared with acyclovir and allow for less frequent daily dosing with higher achievable serum drug concentrations.

The attenuated live varicella virus vaccine is now available in the United States and prevents primary varicella-zoster virus infection in susceptible children and adults.

Erlich KS: Management of herpes simplex and varicella-zoster virus infections. West J Med, 1997 Mar, 166:3, 211-5.

Sequelae (Shingles)

Sequelae

The last 40 years was a period during which the incidence of herpes zoster appears to have increased substantially.

Determined whether the risk of complications of herpes zoster has changed.

Risk increased markedly with age, with those older than 64 years having more than 6 times the risk of complications of those younger than 25 years (odds ratio, 8.3).

Trigeminal distribution of rash and the presence of certain conditions associated with immune compromise appeared to increase risk.

The apparent increase in the incidence of herpes zoster was not accompanied by a change in the risk of specific or overall complications in a population-based sample. Advanced age and other conditions associated with waning cellular immunity may confer an increased risk of experiencing a complicated course of herpes zoster.

Galil K et al., The sequelae of herpes zoster [see comments]. Arch Intern Med, 1997 Jun 9, 157:11, 1209-13.