CFCynthia Firnhaber

Cynthia Firnhaber

*This is an algorithmically generated author record based on publicly available information.

Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Previous Organizations / Institutes

The organizations / institutes from the scholar's other articles in the past ten years


Cynthia Firnhaber has a total of 38 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Pharmacokinetics and Pharmacodynamics of Depot Medroxyprogesterone Acetate in African Women Receiving Treatment for Human Immunodeficiency Virus and Tuberculosis: Potential Concern for Standard Dosing Frequency

    by Rosie Mngqibisa, Michelle A Kendall, Kelly Dooley, Xingye (Shirley) Wu, Cynthia Firnhaber, Helen Mcilleron, Jennifer Robinson, Yoninah Cramer, Susan L Rosenkranz, Jhoanna Roa, et al.

    Effective contraception is critical to young women with HIV-associated tuberculosis (TB), as unintended pregnancy is associated with increased perinatal morbidity and mortality. The effects of co-administration of efavirenz and rifampicin on the pharmacokinetics of depot medroxyprogesterone acetate (DMPA) are unknown. We hypothesized that clearance of medroxyprogesterone acetate (MPA) would increase when given with rifampicin and efavirenz, thus increasing risk of ovulation. This pharmacokinetics (PK) study assessed DMPA among HIV/TB coinfected women on an efavirenz-based antiretroviral treatment and rifampicin-based TB treatment. Plasma MPA concentrations and progesterone were measured predose (MPA only) and 2, 4, 6, 8, 10, and 12 weeks after a single DMPA 150 mg intramuscular injection. The primary outcome measure, MPA concentration (3. Five women (11.9%; 95% CI, 4.0–25.6%) had MPA <0.1 ng/mL at week 12; of these, one had MPA <0.1 ng/mL at week 10. The median clearance of MPA was 19 681 L/week compared with 12 118 L/week for historical controls. There were no adverse events related to DMPA, and progesterone concentrations were <1 ng/mL for all women for the study duration. DMPA, when given with rifampicin and efavirenz, was safe. MPA clearance was higher than in women with HIV not on ART, leading to subtherapeutic concentrations of MPA in 12% of women, suggesting that more frequent dosing might be needed. NCT02412436.


  • Open Access

    Impact of Larger Sputum Volume on Xpert® MTB/RIF Assay Detection of Mycobacterium tuberculosis in Smear-Negative Individuals with Suspected Tuberculosis

    by Sharlaa Badal-Faesen, Cynthia Firnhaber, Michelle A. Kendall, Xingye Wu, Beatriz Grinsztejn, Rodrigo Otavio da Silva Escada, Michel Fernandez, Evelyn Hogg, Ian Sanne, Pamela Johnson, et al.

    As a strategy to improve the sensitivity of nucleic acid-based testing in acid-fast bacilli (AFB) negative samples, larger volumes of sputum (5–10 mL) were tested with Xpert® MTB/RIF from 176 individuals with smear-negative sputum undergoing tuberculosis evaluation. Despite larger volumes, this strategy had a suboptimal sensitivity of 50% (4/8).


  • Open Access

    Characterizing breast conditions at an open-access breast clinic in South Africa: a model that is more than cancer care for a resource-limited setting

    by Sarah Rayne, Naomi Lince-Deroche, Cheryl Hendrickson, Kate Shearer, Faith Moyo, Pam Michelow, Grace Rubin, Carol Benn, Cynthia Firnhaber

    While most breast-related research focuses on cancer, presentation of symptomatic persons in non-screened environments requires understanding the spectrum of breast diseases so as to plan services in resource-constrained settings. This study presents the variety of breast disease managed at a government, open-access breast clinic in South Africa. We performed a retrospective file review using a systematic random sample of patients 18 years and above presenting for breast care over a 14-month period. We collected demographics, clinical characteristics, management and final diagnoses from the first visit and twelve subsequent months. The final sample contained 365 individuals (97 · 5% women). Most were black, unmarried and South African citizens with a median age of 43 years (IQR 31–55) . Of those reporting their status (24 · 1%) 38 · 6% were HIV-positive. A mass (57 · 0%) and/or pain (28 · 5%) were the most common symptoms. Imaging and breast biopsies were required in 78 and 25% of individuals, respectively. Nearly half of biopsies identified breast cancer (44 · 1% of women ≤40 and 57 · 3% for women >40). Benign conditions (47 · 7%) and no abnormality (18 · 2%) were common final classifications among women. There was no difference between the final classifications of patients who self-referred versus those who were formally referred from another health care provider. Nearly half of the participants (46 · 6%) travelled 20 km or more to attend the clinic. Benign breast conditions far outweighed cancer diagnoses. As breast cancer awareness increases in resource-limited countries, facilities offering breast care require administrative and clinical preparation to manage a range of non-cancer related conditions.