Quinine in Pregnancy
Quinine can be used safely in all trimesters of pregnancy for malaria treatment, with a standard dosing regimen of 10 mg/kg three times daily (or 750 mg salt three times daily) for 3-7 days, combined with clindamycin rather than doxycycline to avoid tetracycline-related fetal toxicity. 1, 2
Treatment Positioning
Quinine is positioned as a third-line alternative for uncomplicated P. falciparum malaria in non-endemic settings, behind artemisinin-based combination therapies (ACTs) and atovaquone-proguanil 1. However, for first trimester malaria specifically, quinine-clindamycin remains a WHO-recommended option when ACTs are contraindicated or unavailable 3.
The 2024 guideline explicitly states that artemether-lumefantrine can be used in all trimesters of pregnancy as indicated by WHO and CDC, making it a preferred option over quinine when available 1. For second and third trimesters, ACTs are now first-line.
Dosing Regimens by Trimester
All Trimesters (When Quinine is Selected):
- Quinine sulfate: 750 mg salt (3 tablets of 250 mg) three times daily for 3-7 days
- Plus clindamycin: 20 mg/kg every 8 hours for 7 days (NOT doxycycline, which causes fetal bone/tooth abnormalities)
- Alternative partner: Clindamycin 5 mg/kg every 8 hours for 7 days 1, 4
The quinine-clindamycin combination achieved 100% cure rates at day 42 in a randomized trial of pregnant women in second and third trimesters 4.
Safety Profile
Maternal Safety:
The FDA label and multiple studies involving over 893 pregnant women treated with quinine in the first trimester found no increased incidence of congenital anomalies compared to other antimalarials 2. A large retrospective study showed:
- Stillbirth rate: 1.6% (quinine) vs 1.8% (controls) - not significantly different
- Congenital malformations: 1.4% (quinine) vs 1.7% (controls) - not significantly different
- Spontaneous abortion rate was actually lower with quinine (3.5%) than controls (10.9%) 2
Fetal Considerations:
Quinine crosses the placenta with cord plasma concentrations averaging 32% of maternal levels 2. Fetal quinine levels may not be therapeutic, which is important when considering treatment of congenital malaria.
Critical Monitoring Requirements
Third Trimester - Hypoglycemia Risk:
Monitor glucose levels closely in pregnant women taking quinine, especially in the third trimester, due to increased pancreatic insulin secretion 2. This is the most serious maternal adverse effect requiring active surveillance.
Common Adverse Effects to Expect:
- Cinchonism: Tinnitus (64.5% of treated women), vertigo, headache, acute hearing loss 1, 5
- Nausea and vomiting
- Dizziness
In the quinine-clindamycin trial, 44.9% experienced tinnitus compared to 8.9% with artesunate 4.
Rare but Serious Complications:
Pregnant women are at risk for a rare triad: massive hemolysis, hemoglobinemia, and hemoglobinuria 2. Monitor for signs of hemolysis.
Important Caveats
Labor Concerns:
At therapeutic doses for malaria, quinine does not cause uterine contractions 2. Only doses several times higher than antimalarial doses have been associated with uterine stimulation. The prospective study in Sudan showed only 3.8% abortion rate and 7.7% threatened abortion in first trimester treatment 6.
High-Dose Toxicity:
Case reports describe deafness and optic nerve hypoplasia in children exposed to high doses of quinine in utero 2. These are not seen at therapeutic antimalarial doses.
Gametocyte Carriage:
Quinine results in significantly higher gametocyte carriage (42.5 person-gametocyte-weeks per 1000 woman-weeks) compared to artesunate (3 per 1000) 5, 4. This increases malaria transmission potential but does not affect maternal or fetal outcomes.
Treatment Efficacy Considerations
Parasite clearance with quinine is slower than ACTs, with parasites still present on day 6-7 in 4.7% of cases 5. The 28-day reappearance rate is 28.7% for primary treatments and 44% for re-treatments 5, indicating the need for close follow-up.
For P. vivax malaria in pregnancy, chloroquine or hydroxychloroquine remain first-line with only 4.5% reappearance rate by day 28 1, 5.
Clinical Algorithm
First Trimester:
- If ACTs available and no contraindications → Use artemether-lumefantrine
- If ACTs contraindicated/unavailable → Quinine 750 mg TID + clindamycin 20 mg/kg TID for 7 days
- Monitor glucose levels
- Counsel about tinnitus (expected, reversible)
Second/Third Trimester:
- First-line: Artemether-lumefantrine or dihydroartemisinin-piperaquine
- Alternative: Quinine-clindamycin (same dosing)
- Intensify glucose monitoring in third trimester
- Monitor for hemolysis signs