diff --git a/frontend/services/backend.ts b/frontend/services/backend.ts
index ccdc240..b3b56b4 100644
--- a/frontend/services/backend.ts
+++ b/frontend/services/backend.ts
@@ -239,10 +239,11 @@ export const HybridBackend = {
     return await res.json();
   },
 
-  getGruposFamiliares: async (q?: string) => {
+  getGruposFamiliares: async (q?: string): Promise<import('../types.ts').GrupoFamiliar[]> => {
     const url = q?.trim() ? `${API_URL}/grupos-familiares?q=${encodeURIComponent(q)}` : `${API_URL}/grupos-familiares`;
     const res = await apiFetch(url);
-    return res.json();
+    const data = await res.json();
+    return Array.isArray(data) ? data : [];
   },
 
   criarGrupoFamiliar: async (nome: string, responsavel_id?: string) => {
diff --git a/frontend/views/PatientsView.tsx b/frontend/views/PatientsView.tsx
index d7d6ecc..7e3a5cc 100644
--- a/frontend/views/PatientsView.tsx
+++ b/frontend/views/PatientsView.tsx
@@ -36,7 +36,7 @@ function AutocompleteField<T extends { id: string; nome: string }>({
     useEffect(() => {
         if (!debounced.trim() || value) { setResults([]); setOpen(false); return; }
         setLoading(true);
-        fetchFn(debounced).then(r => { setResults(r); setOpen(r.length > 0); }).finally(() => setLoading(false));
+        fetchFn(debounced).then(r => { const arr = Array.isArray(r) ? r : []; setResults(arr); setOpen(arr.length > 0); }).finally(() => setLoading(false));
     }, [debounced]);
 
     useEffect(() => {
@@ -167,13 +167,13 @@ const AgendamentoModal: React.FC<{ patient: Paciente, onClose: () => void }> = (
         const slots: { time: string, available: boolean }[] = [];
         if (!selectedDentistId || !selectedDate) return slots;
         const startTime = 8 * 60, endTime = 18 * 60, lunchStart = 12 * 60, lunchEnd = 14 * 60;
-        const existingAppointments = agendamentos?.filter(ag =>
+        const existingAppointments = (agendamentos ?? []).filter(ag =>
             ag.dentistaId === selectedDentistId &&
             new Date(ag.start).toISOString().split('T')[0] === selectedDate
         ).map(ag => ({
             start: new Date(ag.start).getHours() * 60 + new Date(ag.start).getMinutes(),
             end: new Date(ag.end).getHours() * 60 + new Date(ag.end).getMinutes(),
-        })) || [];
+        }));
 
         for (let time = startTime; time < endTime; time += duration) {
             const slotStart = time, slotEnd = time + duration;