Alcohol and Medication Interactions - a combination of alcohol and medication can impair driving and machinery operation abilities

Alcohol Research & Health, Wntr, 1999 by Ron Weathermon, David W. Crabb

Acetaldehyde Metabolism in the Liver

As mentioned in the previous section, alcohol breakdown by ADH generates acetaldehyde, which, in turn, is metabolized further by ALDH. Two major types of ALDH (i.e., ALDH1 and ALDH2) exist, which are located in different regions of the cell. ALDH1 requires relatively high acetaldehyde concentrations in the cell to be active, whereas ALDH2 is active at extremely low acetaldehyde levels. Accordingly, ALDH2 may play a particularly important role in acetaldehyde breakdown after moderate alcohol consumption.

The significance of ALDH2 activity in alcohol and acetaldehyde metabolism is further supported by an inborn variation in alcohol metabolism that occurs primarily in people of Asian heritage but which is rare among Caucasians. After consuming alcohol, many Asian people experience an unpleasant "flushing" reaction that can include facial flushing, nausea, and vomiting. These symptoms are caused by acetaldehyde accumulation in the body. Thus, following alcohol consumption, acetaldehyde levels in people susceptible to the flushing reaction may be 10 to 20 times higher than in people who do not experience flushing. Researchers have noted that approximately 40 percent of Asians lack ALDH2 activity because they have inherited one or two copies of an inactive variant of the gene that produces ALDH2 (Goedde et al. 1989). Most of these individuals flush when they consume alcohol. These observations imply that ALDH2 plays a crucial role in maintaining low acetaldehyde levels during alcohol metabolism. Consequently, even inadvertent alcohol administration to people of Asian heritage (who may have inherited an inactive ALDH2 gene) can cause unpleasant reactions. Thus, the potential flushing response should be an important concern for physicians and patients, because many prescription and OTC medications contain substantial amounts of alcohol (see table 1). Physicians and pharmacists therefore must be alert to the possibility that Asian patients may be intolerant of these medications.

Table 1 Alcohol Content of Prescription and Over-the-Counter
Medications

Product                                          Alcohol Content (%)

Betadine (mouthwash, gargle)                              8.8
Cepacol (mouthwash, gargle)                              14.0
Cheracol Sore Throat                                     12.5
Chlortrimeton syrup                                       7.0
Cimetidine Oral Solution                                  2.8
Cyclosporine Oral Solution                           9.5-12.5
Cyproheptadine                                            5.0
DentSure (denture rinse, peppermint)                     14.4
Dr. Tichenor's Antiseptic                               70(*)
Digoxin Elixir                                           10.0
Entex                                                     5.0
Furosemide Liquid                                        11.5
Intensol (diazepam)                                      19.0
Listerine                                                26.9
Listerine Cool Mint or Freshburst                        21.6
Lomotil Liquid                                           15.0
Mellaril/Thioridiazine                                3.0-4.2
Mentadent Mouthwash                                      10.0
Oral-B Anti-Plaque Rinse                                  8.0
Plax-Advanced Formula                                     8.7
Peri-colace                                              10.0
Phenobarbital Elixir                                     14.0
Promethazine/Phenergan                                    7.0
Ranitidine                                                7.5
Scope, Baking Soda                                        9.9
Scope, Cool Peppermint                                   14.0
Senokot Syrup                                             7.0
Targon Smokers' Mouth Wash, Clean Taste               15.6(*)
Targon Smokers' Mouth Wash, Original                  16.0(*)
Tavist Oral Solution                                      5.5
Theophylline Elixir                                      20.0
Viadent Oral Rinse                                       10.0

* Specifically denatured alcohol (SDA) 38B content.

SOURCE: Knodel, L.C., ed. Nonprescription Products: Formulations and
Features. 1998-1999. Washington, DC: American Pharmaceutical
Association, 1999.