Table 2.

Table 2 Signals Associated with Antidotes ^∗

Signal	Number of Studies	PPV Range	p-value Test for Heterogeneity	Overall Estimate of PPV† (95% CI)	Overall Estimate of PPV‡ (95% CI)
Vitamin K given	3	0.02–0.30	<0.01	—	—
Activated charcoal given	2	0.08–0.45	0.03	—	—
Antihistamine (e.g., diphenhydramine or hydroxyzine) given	3	0.03–0.14	<0.01	—	—
Oral metronidazole or vancomycin given	2	0.07–0.16	0.06	0.11 (0.06–0.20)	0.10 (0.06–0.14)
Antidiarrheal (e.g., loperamide, diphenoxylate, bismuth) given	3	0–0.11	0.06	0.09 (0.07–0.13)	0.07 (0.00–0.15)
Sodium polystyrene (Kayexalate®) given	3	0.06–0.12	0.44	0.09 (0.06–0.13)	0.08 (0.05–0.12)
Oral or topical steroids (e.g., prednisone, prednisolone) given	2	0.04–0.09	<0.01	—	—

^∗ Naloxone not included as data were available from only a single study.

^† PPV calculated using GEE pooled estimate and CI.

^‡ PPV calculated using fixed effects pooled estimate and CI.

PPV= positive predictive value.