Al-Nakib et al., 1987 (26) | United Kingdom | 12 | NR | Adults, age 18–50 yr | I | ZG lozenge; 23 mg every 2 h while awake | < 24 | 6 d | NR | NR | Pharma (RBS) |
Douglas et al., 1987 (27) | Australia | 55 | Apr–Nov 1985 | Adults | N | ZA lozenge; 10 mg every 2 h while awake (6–8 daily) | < 48 | Until symptom resolution (minimum 3 d, maximum 6 d) | 14 d | No nasal, throat or cough symptoms | Pharma (Fauldings Ltd.) |
Eby et al., 1984 (28) | United States | 146 | Fall 1981 | Children and adults | N | ZG tablet; loading dose 46 mg, then 23 mg every 2 h while awake | < 72 | Until symptom resolution | 7 d | Absence of all cold symptoms* | Pharma (Truett laboratories) |
Farr et al. (A), 1987 (29) | United States | 32 | NR | Adults | I | ZG lozenge (citric acid); loading dose 46 mg, then 23 mg every 2 h while awake | < 36 | 5 d | NR | NR | Pharma (Bristol Myers) |
Farr et al. (B), 1987 (29) | United States | 45 | NR | Adults | I | ZG lozenge (citric acid); 23 mg every 2 h while awake | < 24 | 7 d | NR | NR | Pharma (Bristol Myers) |
Godfrey et al., 1992 (30) | United States | 87 | NR | Adults | N | ZG lozenge (glycine); 23.7 mg every 2 h while awake (maximum 8) | < 48 | Until symptom resolution | NR | Absence of all cold symptoms* | Pharma (Rorer), Godfrey Science and Design Inc. |
Kurugöl et al., 2006 (31) | Turkey | 200 | Oct 2004–May 2005 | Children, age 2–10 yr | N | ZS syrup; 15 mg twice daily | < 24 | Until symptom resolution (maximum 10 d) | 7 mo | Symptom score ≤ 1† on 2 consecutive days | Pharma (Berko Ilaç) |
Kurugöl et al., 2007 (32) | Turkey | 120 | Dec 2004–Mar 2005 | Children | N | ZS syrup; 15 mg twice daily | < 48 | 10 d | Until symptom resolution or 7 d | Resolution of all or all but one mild symptom* | Pharma (Berko Ilaç) |
Macknin et al., 1998 (33) | United States | 249 | Oct 1996–Mar 1997 | Children, grades 1–12 | N | ZG lozenge (glycine); 10 mg five times daily (grades 1–6) or six times daily (grades 7–12) | < 24 | Until symptom resolution | Until symptom resolution | Absence of nine symptoms* (excluding fever) | Pharma (Quigley) |
Mossad et al., 1996 (34) | United States | 100 | Oct 1994–Nov 1994 | Adults | N | ZG lozenge (glycine); 13.3 mg every 2 h | < 24 | Until symptom resolution | 18 d | Resolution of all or all but one mild symptom* | Pharma (Quigley), Cleveland Clinic Foundation |
Petrus et al., 1998 (35) | United States | 102 | July 1997–Aug 1997 | Adults | N | ZA lozenge; 9 mg every 1.5 h on day 1, then every 2 h while awake | NR | Until symptom resolution (maximum 14 d) | Until symptom resolution | Resolution of 11 cold symptoms (10 listed* plus malaise) | Pharma (Weider Nutrition) |
Prasad et al., 2000 (36) | United States | 50 | Jan 1998–Dec 1998 | Adults | N | ZA lozenge; 12.8 mg every 2–3 h while awake | < 24 | Until symptom resolution | 1 d after symptom resolution | Resolution of all or all but one mild symptom* | George and Patsy Eby Research Foundation |
Prasad et al., 2008 (37) | United States | 50 | Jan 1999–Jan 2003 | Adults | N | ZA lozenge; 13.3 mg every 2–3 h while awake | < 24 | Until symptom resolution | 1 d after symptom resolution | Resolution of all or all but one mild symptom* | George and Patsy Eby Research Foundation, NIH |
Smith et al., 1989 (38) | United States | 174 | Jan 1986–May 1986 | Adults | N | ZG lozenge; loading dose 46 mg, then 23 mg every 2 h while awake | NR | 7 d or until symptom resolution | 7 d | Resolution of 11 symptoms (10 listed* plus chilliness) | Pharma (McNeil Consumer Products) |
Turner et al. (A), 2000 (24) | United States | 273 | NR | Adults, age 18–65 yr | I | ZG or ZA lozenge; ZG 13.3 mg, or ZA 11.5 mg or 5 mg; every 2–3 h (total 6/d) | < 48 | Until symptom resolution (minimum 3 d, maximum 14 d) | 14 d | 2 consecutive symptom scores ≤ 1‡ | Pharma (Warner Lambert Consumer) |
Turner et al. (B), 2000 (24) | United States | 281 | NR | Adults, age 18–65 yr | N | ZG or ZA lozenge; ZG 13.3 mg, or ZA 11.5 mg or 5 mg; every 2–3 h (total 6/d) | < 36 | Until symptom resolution (minimum 3 d, maximum 14 d) | 14 d | 2 consecutive symptom scores ≤ 1‡ | Pharma (Warner Lambert Consumer) |
Weismann et al., 1990 (39) | Denmark | 145 | Feb 1987–Feb 1988 | Adults, age 18–65 yr | N | ZG lozenge; 4.5 mg every 1–1.5 h while awake (10 daily) | < 24 | Until symptom resolution (maximum 10 d) | 10 d | Absence of 9 symptoms (10 listed* plus indisposition and excluding sneezing and scratchy throat) | Pharma (Kirsten B Staehr) |