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Medications

Alcohol and Medications – RGH E-Bulletin

by Robbo on December 17, 2011

Alcohol has the potential to interact with many medications, but the clinical significance of these interactions is often queried. Pharmacokinetic interactions between alcohol and drugs occur mainly in the liver where both are metabolised.

Pharmacodynamic interactions generally result in enhanced effects in the central nervous system (CNS) including sedation and decreased motor skills. Assessment of alcohol-drug interactions is confounded because acute alcohol intake may inhibit drug metabolism whereas chronic alcohol intake can induce enzymes. Studies often focus on the effects of chronic heavy drinking with little evidence for advice around concomitant moderate alcohol consumption.

The table below highlights some key interactions where avoiding alcohol may be prudent (click to enlarge)

Obviously, increased risk of sedation and possibly also other CNS suppression effects is expected with a variety of medications if taken concurrently with alcohol: these include antidepressants, antipsychotics, antihistamines, antiepileptics, opioids and other sedatives. Patients need to be counselled regarding this and should be warned about the risk of decreased motor skills. Caution is also advisable with vasodilators, which if taken with alcohol may lead to increased orthostatic hypotension.

Increased risk of gastric irritation may occur with NSAIDs and prednisolone, and liver damage with methotrexate and isoniazid. Drugs increasing gastric emptying such as erythromycin and H2 antagonists, result in increased alcohol absorption in the small intestine with increased blood alcohol levels.

Alcohol consumption has variable effects on drugs such as phenytoin and oral anticoagulants. Chronic use can result in significantly reduced drug concentrations. Conversely binge drinking inhibits warfarin metabolism resulting in increased risk of bleeding. Consumption of 1-2 standard drinks per day is generally considered to be safe.

Download: Alcohol and medications

Acknowledgment – This E-Bulletin is based on work by Dr Rose Allin, DATIS, RGH.

FOR FURTHER INFORMATION – CONTACT THE PHARMACY DEPARTMENT ON 82751763 or email: chris.alderman@rgh.sa.gov.au
Information in this E-Bulletin is derived from critical analysis of available evidence – individual clinical circumstances should be considered when making treatment decisions. You are welcome to forward this E-bulletin by email to others you might feel would be interested, or to print the E-Bulletin for wider distribution. Reproduction of this material is permissible for purposes of individual study or research.

Tagged as: alcohol, Benzodiazepines, griseofulvin, Kapanol, Medications, metformin, metronidazole, morphine

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Drug-induced photosensitivity reactions – RGH E-Bulletin

by Robbo on November 18, 2011

in Drug Information

Drug induced photosensitivity reactions are a relatively common side effect associated with many medications. These reactions occur via activation of a chemical by ultra-violet or visible light. Many commonly used drugs are implicated (both systemic and topical use), and include amiodarone, NSAIDs, phenothiazines, retinoids, quinolones, sulfonamides, tetracyclines, and thiazides.

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A joint initiative of the Patient Services Section and the Drug and Therapeutics Information Service of the Pharmacy Department, Repatriation General Hospital, Daw Park, South Australia. The RGH Pharmacy E-Bulletin is distributed in electronic format on a weekly basis, and aims to present concise, factual information on issues of current interest in therapeutics, drug safety and cost-effective use of medications.
Editor: Assoc. Prof. Chris Alderman, University of South Australia – Director of Pharmacy, RGH © Pharmacy Department, Repatriation General Hospital, Daw Park, South Australia 5041.

Tagged as: amiodarone, drugs, Medications, NSAIDs, phenothiazines, photosensitivity, quinolones, retinoids, RGH E-bulletin, sulfonamides, tetracyclines

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Smoking, Smoking Cessation and Medications

by Robbo on April 6, 2010

in Drug Information

Tobacco smoking, and cessation of tobacco smoking, is known to affect the handling of various medications. However the significance of the effect smoking can have on medications may not always be considered in clinical practice. As many hospitals and health services (including RGH) work towards becoming smoke-free environments it is timely to highlight potential interactions involving smoking, smoking cessation and medications.

Pharmacodynamic interactions alter the expected response or actions of other drugs. In the case of tobacco smoke, these interactions are largely due to nicotine. Pharmacodynamic interactions with medications and smoking include:
• Combined hormonal contraceptives – risk of cardiovascular disease is increased for women who smoke
• Inhaled corticosteroids – cigarette smoking in asthma is associated with a reduced sensitivity to corticosteroids
• Beta blockers – nicotine stimulation of the sympathetic nervous system may counteract the effects of these drugs

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The 2009 RGH E-Bulletins are archived here.

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A joint initiative of the Patient Services Section and the Drug and Therapeutics Information Service of the Pharmacy Department, Repatriation General Hospital, Daw Park, South Australia. The RGH Pharmacy E-Bulletin is distributed in electronic format on a weekly basis, and aims to present concise, factual information on issues of current interest in therapeutics, drug safety and cost-effective use of medications.
Editor: Assoc. Prof. Chris Alderman, University of South Australia – Director of Pharmacy, RGH © Pharmacy Department, Repatriation General Hospital, Daw Park, South Australia 5041.