Clindamycin: 7 things you should know

Medically reviewed by Carmen Pope, BPharm. Last updated on July 26, 2023.

1. How it works

• Clindamycin is an antibiotic that may be used to treat a wide range of infections including those involving gram-positive and anaerobic bacteria (anaerobic means living without air).
• Clindamycin works by inhibiting bacterial protein synthesis, which inhibits bacterial growth. It has a bacteriostatic effect which means it stops bacteria from reproducing but doesn't necessarily kill them.
• Clindamycin belongs to the class of antibiotics known as lincosamide or lincomycin antibiotics.

2. Upsides

• Usually reserved for the treatment of serious infections caused by susceptible anaerobic bacteria, such as those occurring in the abdomen, gastrointestinal tract, lower respiratory tract, on the skin, and in the genitourinary area. Examples include acute otitis media in people who fail to respond to first-line or other preferred agents, serious bone and joint infections, gynecological infections, or serious intra-abdominal infections.
• Effective against several gram-positive and anaerobic bacteria, including susceptible strains of Staphylococcus aureus (methicillin-susceptible strains only), Streptococcus pneumoniae (penicillin-susceptible strains only), S. pyogenes, Clostridium perfringens, Fusobacterium necrophorum, F. nucleatum, Peptostreptococcus anaerobius, Prevotella melaninogenica.
• For infections caused by susceptible strains of streptococci, pneumococci, or staphylococci, clindamycin is usually reserved for penicillin-allergic patients or other patients in whom penicillin is unsuitable.
• Available as an oral capsule, oral solution, and parenterally (may be administered IM or by intermittent or continuous infusion). The oral capsule should not be given to children who are unable to swallow capsules; use the oral solution instead.
• For serious anaerobic infections, the parenteral route is usually used initially but should be switched to the oral route as soon as the patient's condition allows.
• May be taken with or without food.
• Generic clindamycin is available.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

• Abdominal pain, pain in the esophagus, nausea, vomiting, an unpleasant or metallic taste, skin rashes, and liver function test abnormalities.
• All antibiotics carry a risk of severe diarrhea caused by an overgrowth of Clostridium difficile bacteria. The risk may be higher with clindamycin compared with some other antibiotics. Further investigations are warranted if severe diarrhea occurs within several months of clindamycin administration. Symptoms include watery or bloody stools, stomach cramps, or fever. For this reason, clindamycin should only be used to treat serious infections when less toxic anti-infectives are inappropriate.
• Not suitable for the treatment of meningitis because it does not reach high enough concentrations in the cerebrospinal fluid (the fluid around the brain and spinal cord).
• May not be suitable for some people including those with a history of gastrointestinal disease (such as colitis) or a history of allergic reactions. Rarely, may cause severe hypersensitivity reactions and anaphylaxis.
• Be cautious when using in patients with kidney or liver disease. Although dosage reductions are not specifically recommended, liver and kidney function should be monitored.
• If administered long-term, monitor liver and renal function and blood counts regularly.
• Rapid IV infusion has caused cardiopulmonary arrest and low blood pressure.
• May interact with several drugs including neuromuscular blocking agents (such as succinylcholine, and vecuronium), those that inhibit or induce CYP3A4 hepatic enzymes, and erythromycin.
• Clindamycin needs to be administered every six hours.
• Not effective in nonbacterial infections.
• Injectable clindamycin contains 9.45mg of benzyl alcohol, which may be toxic to children in large amounts and cause a potentially fatal "gasping syndrome").
• Should only be used during pregnancy if the benefits outweigh the risks. Animal studies do not reveal any evidence of teratogenicity and there is not enough data in humans to make a recommendation. Clindamycin is secreted into breast milk and may potentially cause adverse effects on the GI flora of breastfed infants. If used during breastfeeding, monitor the infant for possible adverse effects, such as diarrhea, thrush, or blood in the stool.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

Clindamycin is an antibiotic that is usually reserved for treating anaerobic infections or other serious infections caused by gram-positive bacteria in penicillin-allergic people. The risk of C. difficile-associated diarrhea may be higher with clindamycin compared with some other antibiotics.

5. Tips

• May be taken with or without food. Take with a full glass of water to stop the capsules from becoming inadvertently stuck in your throat.
• Take exactly as directed and for the duration intended. Finish the course of treatment prescribed.
• Only use when prescribed by a doctor to treat infections caused by susceptible bacteria as improper use increases the risk of resistant bacteria developing. Clindamycin does not treat infections caused by viruses, such as a cold or the flu.
• Report any instances of severe or persistent diarrhea, occurring either during clindamycin administration or within a few months following discontinuation to your doctor.
• Call your doctor immediately if you develop a severe rash.
• Some strengths (eg, 150mg capsules) contain FD & C Yellow No. 5 (tartrazine) which may cause allergic reactions; people with an aspirin sensitivity may be more at risk.
• Tell your doctor if you are pregnant or intend to become pregnant because it is not known how clindamycin affects a developing baby. Also, talk to your doctor if you intend to breastfeed while taking clindamycin.
• Tell your doctor about any other medications you take, including those brought over the counter from a pharmacy, supermarket, or health store.

6. Response and effectiveness

• Peak concentrations are reached within 45 minutes; however, it may take up to 48 hours before infection-related symptoms start to abate.

7. Interactions

Medicines that interact with clindamycin may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with clindamycin. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with clindamycin include:

• birth control treatments, such as estradiol, levonorgestrel
• botulinum toxin A
• bowel cleansing agents such as sodium picosulfate
• CYP3A4 inducers, such as erythromycin, diltiazem, itraconazole, ritonavir, or verapamil
• grapefruit juice
• kaolin
• lactobacillus
• neuromuscular blocking agents, such as atracurium or vecuronium
• mycophenolate mofetil
• rifampin
• vaccinations, such as BCG and Cholera.

Clindamycin is a substrate of CYP3A4 and to a lesser extent, CYP3A5. It is a moderate inhibitor of CYP3A4. Drugs that inhibit CYP3A5 or CYP3A4 may cause increased blood concentrations of clindamycin. CYP3A4 or 3A5 inducers may decrease plasma concentrations of clindamycin.

Note that this list is not all-inclusive and includes only common medications that may interact with clindamycin. You should refer to the prescribing information for clindamycin for a complete list of interactions.

References

• Clindamycin. Revised 03/2023. Glenmark Pharmaceuticals INC., USA. https://www.drugs.com/pro/clindamycin-capsules.html

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use clindamycin only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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