Drug and alcohol interactions (Adapted from Drug / Alcohol Interactions – When to be Cautious. Adapted from O’Hagan J, Robinson R, Whiteside E. Alcohol and Drug Problems: Handbook for Health Professionals. Wellington: Alcohol Advisory Council, 1993.)
Drug-alcohol interactions are frequently encountered because they are widely used substances.
Ethanol is metabolised in the liver by a variety of enzymes – mainly alcohol and acetaldehyde dehydrogenses but also by the microsomal enzymes. Chronic ingestion of alcohol stimulates these enzymes and speeds up the metabolism of alcohol and other drugs metabolised by the liver. Acute isolated alcohol intoxication inhibits the enzyme systems and slows down the metabolism and clearance of some drugs. The interactions may be antagonistic, synergistic, potentiating or mutually neutralising in their effect. Ethanol is basically a central nervous system depressant and therefore will have an additive effect when given with tranquillisers, sedatives, sleeping drugs etc., whereas stimulants amphetamine, caffeine, cocaine and possibly nicotine should have an antagonistic effect when co-administered with alcohol. ASPRIN: NSAIDs Interaction
Moderate prolongation of bleeding time and mucosal irritation.
Patients should be warned of the possibility of this interaction especially if they are taking prolonged courses of treatment with non-steroidal anti-inflammatory agents. Gastrointestinal irritation due to these drugs may be worsened by concomitant alcohol intake. When possible, advise no or low alcohol intake.
Acute alcohol intake, even in moderate dosage, potentiates the action of coumarin anticoagulants by competitive inhibition of their hepatic enzyme metabolism. In alcoholics the half-life of warfarin is reduced due to alcohol-induced induction of liver microsomal enzymes.
The most critical factor is that alcohol intake is relatively constant from day to day. For practical purposes it may be desirable to advise patients to avoid alcohol.
ANTICONVULSANT Interaction Increased metabolism of phenytoin can occur with heavy drinking; this can result in the drug failing to control epilepsy. Management Advise to minimise or avoid alcohol. If choose to continue drinking advise a regular intake is safer and to avoid binges. ANTIDRESSANTS/TRICYCLICS/SSRIs/MAOIs Interaction Enhanced sedation, agitation, sleep disturbance. Ability to drive or operate machinery may be grossly impaired. Patients being treated with tricyclic antidepressants who take alcohol may show both unusual and unexpected behavioural disorders. These are usually most noticeable during the first few days of tricyclic antidepressant therapy. Original MAOIs may have caused hypertension (due to the tyramine content of some alcoholic drinks, notably beers and wines) the new MAOIs do not have this effect. Management Advise to minimise or avoid alcohol. H2 ANTAGONISTS Interaction Cimetidine and ranitidine but not famotidine inhibit gastric A.D.H. increasing alcohol absorption, blood levels and clinical effects. Management Patients taking H2 blockers should be warned to limit alcohol intake especially when driving or using machinery etc. ANTIDIABETIC AGENTS: BIGUANIDES (METFORMIN), INSULIN, SULPHONYLUREAS Interaction Acute ingestion of alcohol by patients on insulin or an oral hypoglycaemic drug carries the risk of severe hypoglycaemia due to the hypoglycaemic effects of alcohol. In patients on metaformin dosage, an increased risk of lactic acidosis must also be considered. In alcoholics there is induction of hepatic microsomal enzymes and a reduced half-life of chlorpropamide and tolbutamide. Management Alcohol should only be taken moderately; if therapy is accompanied by calorie restricted diet then alcohol may not be allowed at all. ANTIHYPERTENSIVE AGENT Interaction The hypotensive effect of these drugs may be enhanced due to synergism with the vasodilator effects of alcohol. Alcohol increases the absorption of propranolol. Management Advise to minimise or avoid alcohol. Advise lifestyle interventions for hypertension. If chooses to continue to drink, try downward titration of antihypertensive dose. CNS DEPRESSANTS e.g. barbitiruates, non barbiturate sedatives, hypnotics, minor tranquillisers, benzodiazepines, opioid narcotics. Interaction
Alcohol will enhance the CNS depressant effect. Suicide or accidental death are common especially if alcohol is combined with barbiturates, or opioid narcotics.
Recommend avoiding these combinations especially when driving, where there is suicide risk or severe obstructive airways disease.
MAJOR TRANQUILLISERS e.g. butyrophenones (haloperidol), phenothiazines (including depot-injections), triaxanthenes (thiothixene), atypical antipyschotics: respridone, alanzapine and chlorzapine. Management
The combination is contraindicated in patients who might perform potentially hazardous tasks such as driving.
DISULFIRAM/CALCIUM CARBIMIDE Interaction
Taking alcohol, even in small quantities, after the administration of disulfiram (Antabuse) evokes an extremely unpleasant syndrome of systemic reactions. This effect is due to the inhibition of the oxidation of acetaldehyde, the primary metabolite of alcohol causing an increase of acetaldehyde in the blood. Citrated calcium carbimide (Dipsan) has the same action and uses as disulfiram.
Patients should be given a cardiovascular assessment before starting treatment. OTHER DRUGS WHICH PRODUCE DISULFIRAM-LIKE EFFECTS IN THE PRESENCE OF ALCOHOL e.g. griseofulvin, metronidazole, sulphonylureas, ornidazole, tinidazole. Interaction
Other drugs, whose therapeutic use is quite distinct from the treatment of chronic alcoholism, may produce a disulfiram-like interaction with alcohol. With some, the mechanism involved is thought to be an inhibition of acetaldehyde dehydrogenase.
Patients should be warned against the possibility of interactions with alcohol.
Pædiatric Rheumatology InterNational Trials Organisation Mevalonate kinase Deficiency (MKD) (or Hyper IgD syndrome) What is it? Mevalonate kinase deficiency is a genetic disease. It is an inborn error of the body’s chemistry. Patients suffer from recurrent bouts of fever, accompanied by a variety of symptoms. These include painful swelling of lymph nodes (especially in th
Acetaminophen (Tylenol) Acetaminophen reduces fever and relieves pain. Typical uses include fevers, immunizations, teething, earaches, bruises, headaches, etc. Please notify us prior to using Tylenol for babies under 2 months of age. Acetaminophen is available in the following forms: Infant drops (80mg/0.8 ml) Children's liquid (160mg/5ml) Chewable tablets (80mg) Junior